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‌SPECIFICATIONS

FASTENER SPECIFICATIONS

HVAC

HVAC - Automatic - Volt

Reusable Threaded Fastener Tightening Specifications

SCHEMATIC WIRING DIAGRAMS

HVAC WIRING SCHEMATICS

Power, Ground, Data Communication and Blower Controls

Fig. 1: Power, Ground, Data Communication and Blower Controls Courtesy of GENERAL MOTORS COMPANY

Temperature Sensors

Fig. 2: Temperature Sensors

Courtesy of GENERAL MOTORS COMPANY

Compressor Controls

Fig. 3: Compressor Controls

Courtesy of GENERAL MOTORS COMPANY

Cabin Heater

Fig. 4: Cabin Heater

Courtesy of GENERAL MOTORS COMPANY

Actuators

Fig. 5: Actuators

Courtesy of GENERAL MOTORS COMPANY

DIAGNOSTIC INFORMATION AND PROCEDURES

HVAC COMPONENT REPLACEMENT REFERENCE

DTC B0163: PASSENGER COMPARTMENT TEMPERATURE SENSOR CIRCUIT

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0163 02

Passenger Compartment Temperature Sensor Circuit Short to Ground

DTC B0163 05

Passenger Compartment Temperature Sensor Circuit High Voltage/Open

Diagnostic Fault Information

Circuit/System Description

The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor. This sensor assembly provides information about:

Sun heat intensity

Passenger compartment temperature

The vehicle uses a sunload sensor that is integrated into one sensor assembly along with the passenger compartment temperature sensor. Low reference and signal circuits enable the sensor to operate. The sensor signal varies between 0 - 5 V.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0 - 5 V.

Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Conditions for Running the DTC

Vehicle in Service Mode.

The HVAC control module is ON.

Conditions for Setting the DTC

B0163 02 or B0163 05

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V or greater than 4.9 V for more than 50 ms.

Action Taken When the DTC Sets

The system will use the last valid values as default.

If no value is read at the time of fault, the HVAC control module uses 0 W/m2 .

Conditions for Clearing the DTC

B0163 02 or B0163 05

The sensor signal is within specified range between 0.1 - 4.9 V.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 60 Ω between the low reference circuit terminal 6 and ground.

If 60 Ω or greater

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC Control Module.

2. Test for less than 2 Ω in the low reference circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC Control Module.

If less than 60 Ω

3. Vehicle in Service Mode.

4. Verify the scan tool Passenger Compartment Air Temperature (Unfiltered) parameter is less than-37°C (-35°F).

If -37°C (-35°F) or greater

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC Control Module.

2. Test for infinite resistance between the signal circuit terminal 4 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module.

If less than -37°C (-35°F)

5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the low reference circuit terminal 6.

6. Verify the scan tool Passenger Compartment Air Temperature (Unfiltered) parameter is greater than 110°C (240°F).

If 110°C (240°F) or less

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC Control Module, vehicle in Service Mode.

2. Test for less than 1 V between the signal circuit and ground.

If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V

3. Vehicle OFF

4. Test for less than 2 Ω in the signal circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC control module.

If greater than 110°C (240°F)

7. Test or replace the B10B Ambient Light/Sunload Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for HVAC control module replacement, programming and setup

DTC B0173 OR B0178: UPPER LEFT DUCT AIR TEMPERATURE SENSOR CIRCUIT/LOWER LEFT DUCT AIR TEMPERATURE SENSOR CIRCUIT

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0173 02

Upper Left Duct Air Temperature Sensor Circuit Short to Ground

DTC B0173 05

Upper Left Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B0178 02

Lower Left Duct Air Temperature Sensor Circuit Short to Ground

DTC B0178 05

Lower Left Duct Air Temperature Sensor Circuit High Voltage/Open

Diagnostic Fault Information

Circuit/System Description

The air temperature sensors are 2-wire negative temperature co-efficient thermistors. The vehicle uses the following air temperature sensors:

Air temperature sensor left upper Air temperature sensor left lower

A signal and low reference circuit enables the sensor to operate. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor signal voltage decreases as the resistance decreases. The sensor operates within a temperature range between -40 to +85°C (-40 to +185°F). The sensor signal varies between 0 - 5 V. The HVAC control module converts the signal to a range between 0 - 255 counts. As the air temperature increases the count value will decrease. If the HVAC control module detects a malfunctioning sensor, then the control module software will use a default air temperature value. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is corrected.

Conditions for Running the DTC The vehicle is turned ON. Conditions for Setting the DTC

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V or greater than 4.9 V for more than 50 ms.

Action Taken When the DTC Sets

A default value is used when the DTC is set.

Conditions for Clearing the DTC

The DTC will become history if the HVAC control module no longer detects a failure. The history DTC will clear after 100 fault-free ignition cycles.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate temperature sensor. It may take up to 10 minutes for all vehicle systems to power down.

2. Test for less than 10 Ω between the low reference circuit terminal B and ground.

If 50 Ω or greater

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module.

2. Test for less than 2 Ω in the low reference circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC control module.

If less than 10 Ω

3. Vehicle in Service Mode.

4. Verify the scan tool parameter is less than -37°C (-35°F). Lower Left Duct Air Temperature Sensor

Upper Left Duct Temperature Sensor

If greater than -37°C (-35°F)

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module.

2. Test for infinite resistance between the signal circuit terminal A and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module.

If -37°C (-35°F) or less

5. Install a 3 A fused jumper wire between the signal circuit and the low reference circuit terminal B.

6. Verify the scan tool parameter is greater than 110°C (230°F). Lower Left Duct Air Temperature Sensor

Upper Left Duct Temperature Sensor

If 110°C (230°F) or less

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, vehicle in Service Mode.

2. Test for less than 1 V between the signal circuit and ground.

If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V

3. Vehicle OFF

4. Test for less than 2 Ω in the signal circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC control module.

If greater than 110°C (230°F)

7. Test or replace the temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup

DTC B018A, B048C, B048F, OR B1395: WINDSHIELD TEMPERATURE SENSOR CIRCUIT/HUMIDITY SENSORCONTROL MODULE VOLTAGE

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B018A 02

Windshield Temperature Sensor Circuit Short to Ground

DTC B018A 05

Windshield Temperature Sensor Circuit High Voltage/Open

DTC B048C 02

Humidity Sensor Humidity Circuit Short to Ground

DTC B048C 05

Humidity Sensor Humidity Circuit High Voltage/Open

DTC B048F 02

Humidity Sensor Temperature Circuit Short to Ground

DTC B048F 05

Humidity Sensor Temperature Circuit High Voltage/Open

DTC B1395 03

Control Module Voltage Reference Output Circuit Low Voltage

DTC B1395 07

Control Module Voltage Reference Output Circuit High Voltage

Diagnostic Fault Information

Circuit/System Description

The windshield temperature and inside moisture sensor integrates the relative humidity sensor, windshield temperature sensor and humidity sensing element temperature sensor.

This sensor assembly provides information about:

Relative humidity level on inside windshield Temperature of the inside windshield

Temperature of the humidity sensor element

The relative humidity sensor measures the relative humidity on the compartment side of the windshield. It also detects the temperature of the windshield surface on the compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield. The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element. It is only needed if the thermal contact between the humidity sensing element and the inside windshield surface is not sufficient.

Conditions for Running the DTC

Vehicle ON or Vehicle in Service Mode. The HVAC control module is ON.

Conditions for Setting the DTC

B018A 02, B048C 02, B048C 02 or B1395 03

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V for more than 50 ms.

B018A 05, B048C 05, B048C 05 or B1395 07

The HVAC control module detects the sensor signal out of range. The signal voltage is greater than 4.9 V for more than 50 ms.

Action Taken When the DTC Sets

The system will use the last valid values as default.

If no value is read at the time of fault, the HVAC control module uses 60% for humidity.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B160 windshield temperature and inside moisture sensor. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 60 Ω between the low reference circuit terminal 3 and ground.

If 60 Ω or greater

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module.

2. Test for less than 2 Ω in the low reference circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC control module.

If less than 60 Ω

3. Vehicle in Service Mode.

4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 1 and ground.

If less than 4.8 V

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module.

2. Test for infinite resistance between the 5 V reference circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance

3. Test for less than 2 Ω in the 5 V reference circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC control module.

If greater than 5.2 V

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, Vehicle in Service Mode.

2. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit.

If less than 1 V, replace the K33 HVAC control module.

If between 4.8 - 5.2 V

5. Verify the scan tool parameters listed below are less than -37°C (-35°F). Windshield Temperature

Passenger Compartment Humidity Sensor Temperature

If -37°C (-35°F) or greater

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module.

2. Test for infinite resistance between the signal circuit terminals listed below and ground: Windshield temperature sensor signal terminal 4

Passenger compartment humidity sensor temperature signal terminal 5 If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module.

If less than -37°C (-35°F)

6. Verify the scan tool Passenger Compartment Humidity parameter is greater than 95%.

If 95% or less

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module.

2. Test for infinite resistance between the signal circuit terminal 2 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module.

If greater than 95%

7. Install a 3 A fused jumper wire between each signal circuit terminal listed below and the low reference circuit terminal 3 one at a time.

Windshield temperature sensor signal terminal 4

Passenger compartment humidity sensor temperature signal terminal 5

8. Verify the appropriate scan tool parameter listed below is greater than 114°C (238°F). Windshield Temperature

Passenger Compartment Humidity Sensor Temperature

If 114°C (238°F) or less

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module.

2. Test for less than 1 V between the signal circuit terminals listed below and ground: Windshield temperature sensor signal terminal 4

Passenger compartment humidity sensor temperature signal terminal 5 If 1 V or greater, repair the short to voltage on the circuit.

If less than 1 V

3. Test for less than 2 Ω in the signal circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC control module.

If greater than 114°C (238°F)

9. Install a 3 A fused jumper wire between the passenger compartment humidity sensor signal circuit terminal 2 and the low reference circuit terminal 3.

10. Verify the scan tool Passenger Compartment Humidity parameter is less than 5%.

If 5% or greater

1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module.

2. Test for less than 2 Ω in the signal circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC control module.

If less than 5%

11. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, Vehicle in Service Mode.

12. Test for less than 1 V between the signal circuit terminal 2 and ground.

If 1 V or greater

Repair the short to voltage on the circuit.

If less than 1 V

13. Test or replace the B160 windshield temperature and inside moisture sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for HVAC control module replacement, programming and setup

DTC B0183: SOLAR LOAD SENSOR CIRCUIT

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0183 02

Solar Load Sensor Circuit Short to Ground

DTC B0183 05

Solar Load Sensor Circuit High Voltage/Open

Diagnostic Fault Information

Circuit/System Description

The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor. This sensor assembly provides information about:

Sun heat intensity

Passenger compartment temperature

The vehicle uses a sunload sensor that is integrated into one sensor assembly along with the passenger compartment temperature sensor. Low reference and signal circuits enable the sensor to operate. The sensor signal varies between 0 - 5 V.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0 - 5 V.

Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Conditions for Running the DTC

Vehicle in Service Mode.

The HVAC control module is ON.

Conditions for Setting the DTC

B0163 02 or B0163 05

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V or greater than 4.9 V for more than 50 ms.

B0183 02

The 5 V identification pulse is not received.

B0183 05

The input signal is static and greater than 4.8 V.

Action Taken When the DTC Sets

The system will use the last valid values as default.

If no value is read at the time of fault, the HVAC control module uses 0 W/m2 .

Conditions for Clearing the DTC

B0163 02 or B0163 05

The sensor signal is within specified range between 0.1 - 4.9 V.

B0183 02 or B0183 05

The sensor signal is within specified range between 0.1 - 4.9 V.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 60 Ω between the low reference circuit terminal 6 and ground.

If 60 Ω or greater

1. Vehicle OFF, disconnect the X1 harness connector at the K33 HVAC control module.

2. Test for less than 2 Ω in the low reference circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC control module.

If less than 60 Ω

3. Vehicle in Service Mode.

4. Test for 4.8 - 5.2 V between the signal circuit terminal 4 and ground.

If less than 4.8 V

1. Vehicle OFF, disconnect the X1 harness connector at the K33 HVAC control module.

2. Test for infinite resistance between the signal circuit terminal 4 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance

3. Test for less than 2 Ω in the signal circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC control module

If greater than 5.2 V

1. Vehicle OFF, disconnect the X1 harness connector at the K33 HVAC control module, Vehicle in Service Mode.

2. Test for less than 1 V between the signal circuit and ground.

If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K33 HVAC control module.

If between 4.8 - 5.2 V

5. Replace the B10B Ambient Light/Sunload Sensor.

6. Verify DTC B0183 does not set while operating the vehicle under the Conditions for Running the DTC.

If the DTC sets

Replace the K33 HVAC control module

If the DTC does not set

7. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for HVAC control module replacement, programming and setup

DTC B0193: FRONT BLOWER MOTOR SPEED CIRCUIT

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0193 01

Front Blower Motor Speed Circuit Short to Battery

DTC B0193 06

Front Blower Motor Speed Circuit Low Voltage/Open

Diagnostic Fault Information

Circuit/System Description

The blower motor speed control signal from the HVAC control module, battery positive and ground circuits enable the blower motor to operate. The blower motor control circuitry is integrated within the blower motor assembly. The HVAC control module provides a ground pulse width modulation (PWM) signal to the blower motor to request a specific motor speed. The blower motor translates the PWM signal and drives the motor accordingly.

Conditions for Running the DTC

Vehicle ON.

The HVAC Control Module is ON.

Conditions for Setting the DTC

B0193 01

The voltage at the HVAC Control Module output to the blower motor control module is always high.

B0193 06

The voltage at the HVAC Control Module output to the blower motor control module is always low or

fluctuating.

Action Taken When the DTC Sets The blower motor is inoperative. Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Diagnostic Aids

The design of this motor does not allow for bench testing. The motor will not operate by simply applying power and ground.

Inspect the motor shaft for rust or other foreign material which may prohibit proper motor operation. Check for Preliminary Information or Technical Service Bulletins.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the M8 Blower Motor. It may take up to 10 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the ground circuit terminal 6 and ground.

If 10 Ω or greater

1. Vehicle OFF.

2. Test for less than 2 Ω in the ground circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.

If less than 2 Ω, repair the open/high resistance in the ground connection.

If less than 10 Ω

3. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.

If the test lamp does not illuminate and the circuit fuse is good

1. Vehicle OFF, remove the test lamp.

2. Test for less than 2 Ω in the B+ circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.

If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.

If the test lamp does not illuminate and the circuit fuse is open

1. Vehicle OFF, remove the test lamp.

2. Test for infinite resistance between the B+ circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the M8 Blower Motor.

If the test lamp illuminates

4. Remove the test lamp.

5. Vehicle in Service Mode. Test for less than 1 V between the control circuit terminal 2 and ground.

If 1 V or greater

1. Vehicle OFF, disconnect the X2 harness connector at the K33 HVAC Control Module. Vehicle in Service Mode.

2. Test for less than 1 V between the control circuit and ground.

If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K33 HVAC Control Module

If less than 1 V

6. Vehicle OFF. It may take up to 10 min for all vehicle systems to power down.

7. Test for infinite resistance between the control circuit terminal 2 and ground.

If less than infinite resistance

1. Disconnect the X2 harness connector at the K33 HVAC Control Module.

2. Test for infinite resistance between the control circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC Control Module

If infinite resistance

NOTE: Verify the ignition is OFF before connecting the blower motor or incorrect test results may occur.

8. Vehicle OFF, connect the harness connector at the M8 Blower Motor. Vehicle in Service Mode.

9. While backprobing terminal 2 at the M8 Blower Motor, test for greater than 1 V between control circuit and ground.

If less than 1 V

Replace the M8 Blower Motor.

If 1 V or greater

10. Verify the voltage decreases and increases while using the controls to change the blower speed selection.

If the voltage does not decrease and increase as the blower speed selection is changed

1. Vehicle OFF, disconnect the X2 harness connector at the K33 HVAC Control Module.

2. Test for less than 2 Ω in the control circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC Control Module.

If the voltage decreases and increases as the blower speed selection is changed

11. Replace the M8 Blower Motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup

DTC B0223, B0233, B023A, OR B0408: RECIRCULATE POSITION COMMAND 1 CIRCUIT/AIR FLOW CONTROL CIRCUIT/HVAC ACTUATORS SUPPLY VOLTAGE/MAIN TEMPERATURE CONTROL CIRCUIT

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0223

Recirculate Position Command 1 Circuit

DTC B0233

Air Flow Control Circuit

DTC B023A

HVAC Actuators Supply Voltage

DTC B0408

Main Temperature Control Circuit

For symptom byte information refer to Symptom Byte List .

Diagnostic Fault Information

Circuit/System Description

Stepper motors are used for temperature regulation, air distribution control and recirculation flap control.

With the appropriate switches at the HVAC control, the desired door positions can be selected. The selected values are passed to the HVAC control module via serial data. The HVAC control module supplies a 12 V reference voltage to the stepper motors and energizes the stepper motors with a pulsed ground signal. The stepper motors put the appropriate door into the calculated position in order to reach the desired temperature, mode. and recirculation position.

Conditions for Running the DTC

Vehicle on, or in Service Mode.

The HVAC control module is ON.

Conditions for Setting the DTC

B023A 02

The stepper motors supply output is shorted to ground.

B0223 01, B0233 01 or B0408 01

At least one control output (of 4 possible outputs) of the appropriate stepper motor is shorted to voltage when motor starts moving. Faults are not detected when motor is already running or target position is already reached.

B0223 06, B0233 06 or B0408 06

At least one control output (of 4 possible outputs) of the appropriate stepper motor is shorted to ground or open when motor starts moving. Faults are not detected when motor is already running or target position is already reached.

Action Taken When the DTC Sets

B023A 02

The affected output will be switched off for hardware protection. All stepper motors are deactivated.

B0223, B0233 or B0408

The affected output will be switched off for hardware protection. The affected stepper motor is deactivated.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Diagnostic Aids

During diagnosis, it is important to verify that the air control door and any associated components (linkage, cams, gears, etc.) operate properly. Inspect for any conditions that may limit or prevent the air control door from moving smoothly or moving through its full range of travel. Any mechanical issues should be corrected first, before proceeding with electrical diagnosis.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Perform the Actuator Recalibration procedure.

2. Verify the concern or DTC has been corrected.

If the concern or DTC has not been corrected

1. Verify DTC B023A is not set.

If DTC B023A is set, refer to Circuit/System Testing - DTC B023A

If DTC B023A is not set, refer to Circuit/System Testing - DTC B0223, B0233 or B0408.

If the concern or DTC has been corrected

3. All OK.

Circuit/System Testing

DTC B023A

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the components listed below. It may take up to 2 min for all vehicle systems to power down.

M37 Mode Door Actuator

M46 Air Recirculation Door Actuator M6 Air Temperature Door Actuator

2. Disconnect the X3 harness connector at the K33 HVAC Control Module.

3. Test for infinite resistance between the K33 HVAC Control Module circuit terminal 15 X3 and ground.

If less than infinite resistance

Repair the short to ground on the circuit.

If infinite resistance

4. Vehicle OFF, connect the X3 harness connector at the K33 HVAC Control Module, Vehicle in Service Mode.

5. Verify DTC B023A is not set.

If the DTC is set.

Replace the K33 HVAC Control Module.

If the DTC is not set.

6. Verify DTC B023A does not set after connecting each of the components listed below one at a time and operating them through their full range.

M37 Mode Door Actuator

M46 Air Recirculation Door Actuator

M6 Air Temperature Door Actuator

If the DTC sets after connecting one of the components

Replace the actuator that was connected immediately before the DTC set.

If the DTC does not set

7. All OK.

DTC B0223, B0233 or B0408

1. Vehicle OFF, disconnect the harness connector at the appropriate door actuator, It may take up to 2 min for all vehicle systems to power down. Vehicle in Service Mode.

NOTE: If more than one actuator is affected, test the B+ circuit at each actuator.

2. Verify a test lamp illuminates between the B+ circuit terminal 2 and ground.

If the test lamp does not illuminate

1. Vehicle OFF, disconnect the X3 harness connector at the K33 HVAC control module.

2. Test for infinite resistance between the control circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance

3. Test for less than 2 Ω in the control circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC control module.

If the test lamp illuminates

3. Command the appropriate actuator with a scan tool.

4. Verify a test lamp is flashing on and off when connected between the B+ circuit terminal 2 and each control circuit terminal listed below:

Control Circuit - terminal 1 Control Circuit - terminal 3 Control Circuit - terminal 4 Control Circuit - terminal 6

If the test lamp is always OFF

1. Vehicle OFF, disconnect the X3 harness connector at the K33 HVAC control module. Vehicle in Service Mode.

2. Test for less than 1 V between the control circuit and ground.

If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V

3. Vehicle OFF.

4. Test for less than 2 Ω in the control circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC Control Module.

If the test lamp is always ON

1. Vehicle OFF, disconnect the X3 harness connector at the K33 HVAC control module.

2. Test for infinite resistance between the control circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC Control Module.

If the test lamp is flashing On and Off

5. Test or replace the actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup

DTC B048E: AUXILIARY HEATER SYSTEM

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B048E 00

Auxiliary Heater System Malfunction

DTC B048E 39

Auxiliary Heater System Internal Malfunction

DTC B048E 58

Auxiliary Heater System Incorrect Reaction After Event

DTC B048E 5A

Auxiliary Heater System Plausibility Failure

Circuit/System Description

The coolant heater control module is a high voltage electric heater. Fused high voltage is supplied from the hybrid/EV battery pack. A fused battery input, ground, and LIN serial data from the HVAC control module are used to control the operation of the coolant heater control module.

The HVAC control module requests heater operation if the coolant temperature is low and additional heat is required to meet the desired settings of the HVAC system.

The coolant heater control module monitors itself during operation, and if a fault is detected a message is sent to the HVAC control module. The HVAC control module then sets the DTC.

Conditions for Running the DTC

12 V battery system voltage is greater than 10.2 V. The HVAC control module is ON.

The electrical auxiliary heater is commanded ON.

Conditions for Setting the DTC

B048E 00

The coolant heater control module reports a recoverable fault for greater than 30 seconds. The condition is present for 3 consecutive ignition cycles

The HVAC control module sets the DTC on the fourth ignition cycle

B048E 39

The coolant heater control module reports an internal malfunction for greater than 30 seconds. The condition is present for 3 consecutive ignition cycles

The HVAC control module sets the DTC on the fourth ignition cycle

B048E 58

The coolant heater control module reports a limited operation status for greater than 10 minutes. The condition is present for 3 consecutive ignition cycles

The HVAC control module sets the DTC on the fourth ignition cycle

B048E 5A

The HVAC control module determines the coolant temperature reported by the coolant heater control module is not rational based on the vehicle operating conditions for greater than 10 minutes.

The condition is present for 3 consecutive ignition cycles

The HVAC control module sets the DTC on the fourth ignition cycle

Action Taken When the DTC Sets

The DIC displays the Service Heater Soon message

The coolant heater is inoperative, or operates in a limited state.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Diagnostic Aids

Verify the cooling system is full before performing diagnostics. A low or aerated coolant condition may cause this DTC to set.

Insufficient or no coolant flow through the coolant heater due to a restriction, blockage, or coolant pump malfunction may cause this DTC to set.

Insufficient or no voltage from the Hybrid/EV battery may cause this DTC to set.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: Check for bulletins before proceeding.

1. Verify that no other DTCs are set.

If any other DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

If no other DTCs are set

2. Verify that DTC B048E 39 is not set.

If DTC B048E 39 is set

Replace the K10 Coolant Heater Control Module

If DTC B048E 39 is not set

3. Verify that DTC B048E 00 is not set.

If DTC B048E 00 is set

Refer to Circuit/System Testing

If DTC B048E 00 is not set

4. Verify the cooling system is filled to the proper level.

If the cooling system is not filled to the proper level

1. Diagnose and correct the cause of the improper coolant level.

2. Fill the cooling system to the proper level. Refer to Cooling System Draining and Filling .

3. Clear DTCs and re-evaluate the concern.

If the cooling system is filled to the proper level

5. Verify the scan tool ECM Engine Coolant Temperature sensor parameter is within 5°C (9°F) of the Ambient Air Temperature sensor parameter.

If the ECM Engine Coolant Temperature sensor parameter is NOT within 5°C (9°F) of the Ambient Air Temperature sensor parameter

Allow the engine to cool until the ECM Engine Coolant Temperature sensor parameter is within 5°C (9°F) of the Ambient Air Temperature sensor parameter.

If the ECM Engine Coolant Temperature sensor parameter is within 5°C (9°F) of the Ambient Air Temperature sensor parameter

6. Verify the G36 Auxiliary Heater Coolant Pump operates when commanding the Auxiliary Coolant Pump On and Off with a scan tool.

If the G36 Auxiliary Heater Coolant Pump does not operate

Refer to Auxiliary Heater Coolant Pump Malfunction.

If the G36 Auxiliary Heater Coolant Pump operates

7. Vehicle ON, HVAC system set to hot, blower set to high. Command the Passenger Compartment Heater Coolant Control Solenoid Valve to bypass.

8. Verify the scan tool parameter Coolant Heater Control Module Status displays only Normal Running.

If the scan tool parameter Coolant Heater Control Module Status displays only Limited Operation

1. Verify the scan tool parameter Coolant Heater Control Module Inlet Coolant Temperature is less than 60°C (140°F) and the parameter Coolant Heater Current is greater than 15 A.

If the scan tool parameter Coolant Heater Control Module Inlet Coolant Temperature is less than 60°C (140°F) and the parameter Coolant Heater Current is less than 15 A, replace the K10 Coolant Heater Control Module

If the scan tool parameter Coolant Heater Control Module Inlet Coolant Temperature is less than 60°C (140°F) and the parameter Coolant Heater Current is greater than 15 A, refer to step 10.

If the scan tool parameter Coolant Heater Control Module Status switches between Limited Operation and Normal Running.

Refer to step 12

If the scan tool parameter Coolant Heater Control Module Status displays only Normal Running

9. Continue to operate the system for 10 min.

10. Verify the scan tool parameter Coolant Heater Control Module Inlet Coolant Temperature is within 5°C (9°F) of parameter Desired Heater Core Outlet Coolant temperature.

If the scan tool parameter Coolant Heater Control Module Inlet Coolant Temperature is not within 5°C (9°F) of parameter Desired Heater Core Outlet Coolant temperature.

Replace the K10 Coolant Heater Control Module

If the scan tool parameter Coolant Heater Control Module Inlet Coolant Temperature is within 5°C (9°F) of parameter Desired Heater Core Outlet Coolant temperature.

11. Vehicle OFF. Inspect the cooling system for restrictions or blockages in coolant flow. Refer to Heating Performance Diagnostic .

If restrictions or blockages in coolant flow are found.

1. Diagnose and correct the cause of the restrictions or blockage.

2. Verify the G36 Auxiliary Heater Coolant Pump operates.

3. Clear DTCs and re-evaluate the concern.

If no restrictions or blockages are found

12. Vehicle ON, engine running, HVAC system set to hot, blower set to high. Command the Passenger Compartment Heater Coolant Control Solenoid Valve to link.

13. Verify the scan tool parameter Coolant Heater Control Module Inlet Coolant Temperature is equal to Engine Coolant Temperature.

If the scan tool parameter Coolant Heater Control Module Inlet Coolant Temperature is not equal to Engine Coolant Temperature

1. Verify there are no ECM engine coolant temperature related DTCs

If ECM engine coolant temperature DTCs are present, refer to Diagnostic Trouble Code (DTC) List - Vehicle , then clear DTCs and re-evaluate the concern.

If no ECM engine coolant temperature DTCs are present, replace the K10 Coolant Heater Control Module.

If the scan tool parameter Coolant Heater Control Module Inlet Coolant Temperature is equal to Engine Coolant Temperature.

14. All OK.

Circuit/System Testing

NOTE: Perform Circuit/System Verification before Circuit/System Testing.

WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.

The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage.

Identify how to test for the presence of high voltage.

Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.

Failure to follow the procedures exactly as written may result in serious injury or death.

1. Vehicle OFF, disable the high voltage at the A4 Hybrid/EV Battery Pack. Refer to High Voltage Disabling .

2. Disconnect the X4 harness connector at the A4 Hybrid/EV Battery Pack and the X2 harness connector at the K10 Coolant Heater Control Module. Refer to High Voltage Connectors .

3. Test for less than 2 Ω end to end between the 300-Volt Positive and Negative Cable circuit terminals listed below:

A4 Hybrid/EV Battery Pack harness connector terminal 1 X4 and K10 Coolant Heater Control Module harness connector terminal 1 X2.

A4 Hybrid/EV Battery Pack harness connector terminal 2 X4 and K10 Coolant Heater Control Module harness connector terminal 2 X2.

If 2 Ω or greater

Replace the 300-Volt Positive and Negative Cable.

If less than 2 Ω

4. Verify the F3HA K10 Coolant Heater fuse is not open. Refer to High Voltage Battery Disconnect Relay Fuse Replacement (Front - BDU) High Voltage Battery Disconnect Relay Fuse Replacement (Rear - BDU) .

If the F3HA K10 Coolant Heater fuse is open

Replace the fuse and the K10 Coolant Heater Control Module.

If the F3HA K10 Coolant Heater fuse is not open

5. Replace the K10 Coolant Heater Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup.

DTC B3844: ENGINE COOLANT CIRCULATION PUMP CIRCUIT

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B3844 01

Engine Coolant Circulation Pump Circuit Short to Battery

DTC B3844 06

Engine Coolant Circulation Pump Circuit Low Voltage/Open

Diagnostic Fault Information

Circuit/System Description

The coolant heater pump is controlled by a relay. When operating conditions exist that requires coolant flow when the engine is not operating, the HVAC control module turns ON the heater coolant pump by applying ground to the relay control circuit which energizes the heater coolant pump relay.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Vehicle in Service Mode.

2. Verify the G36 Auxiliary Heater Coolant Pump operates when commanding the Auxiliary Coolant Pump Relay On and Off with a scan tool.

If the G36 Auxiliary Heater Coolant Pump does not operate

Refer to Circuit/System Testing

If the G36 Auxiliary Heater Coolant Pump operates

3. All OK.

Circuit/System Testing

1. Vehicle OFF, disconnect the X3 harness connector at the X50A Fuse Block- Underhood.

2. Connect a test lamp between the control circuit terminal 17 and B+, Vehicle in Service Mode.

3. Verify the test lamp turns ON and OFF when commanding the Auxiliary Coolant Pump Relay On and Off with a scan tool.

If the test lamp is always OFF

1. Vehicle OFF, remove the test lamp, disconnect the X2 harness connector at the K33 HVAC Control Module, Vehicle in Service Mode.

2. Test for less than 1 V between the control circuit and ground.

If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V

3. Vehicle OFF.

4. Test for less than 2 Ω in the control circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K33 HVAC Control Module.

If the test lamp is always ON

1. Vehicle OFF, remove the test lamp, disconnect the X2 harness connector at the K33 HVAC Control Module.

2. Test for infinite resistance between the control circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC Control Module.

If the test lamp turns ON and OFF

4. Vehicle OFF and all vehicle systems OFF, connect the X3 harness connector at the X50A Fuse Block- Underhood. Disconnect the harness connector at the G36 Auxiliary Heater Coolant Pump. It may take up to 2 min for all vehicle systems to power down.

5. Test for less than 10 Ω between the ground circuit terminal 1 and ground.

If 10 Ω or greater

1. Vehicle OFF.

2. Test for less than 2 Ω in the ground circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.

If less than 2 Ω, repair the open/high resistance in the ground connection.

If less than 10 Ω

6. Connect a test lamp between the control circuit terminal 2 and ground.

7. Verify the test lamp turns ON and OFF when commanding the Auxiliary Coolant Pump Relay ON and OFF with a scan tool.

If the test lamp is always OFF and the circuit fuse is good

1. Vehicle OFF, remove the test lamp, disconnect the X3 harness connector at the X50A Fuse Block- Underhood.

2. Test for less than 2 Ω in the control circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the X50A Fuse Block- Underhood.

If the test lamp is always OFF and the circuit fuse is open

1. Vehicle OFF, remove the test lamp.

2. Test for infinite resistance between the control circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit.

If infinite resistance, test or replace the G36 Auxiliary Heater Coolant Pump.

If the test lamp is always ON

1. Vehicle OFF, disconnect the disconnect the X3 harness connector at the X50A Fuse Block- Underhood, Vehicle in Service Mode.

2. Test for less than 1 V between the control circuit and ground.

If 1 V or greater, repair the short to voltage on the circuit.

If less than 1 V, replace the X50A Fuse Block- Underhood.

If the test lamp turns ON and OFF

8. Test or replace the G36 Auxiliary Heater Coolant Pump.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup

DTC P0531, P0532, OR P0533: AIR CONDITIONING (A/C) REFRIGERANT PRESSURE SENSOR

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of the diagnostic category.

DTC Descriptors

DTC P0531

Air Conditioning (A/C) Refrigerant Pressure Sensor Performance

DTC P0532

Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit Low Voltage

DTC P0533

Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit High Voltage

Diagnostic Fault Information

Circuit/System Description

The engine control module monitors the high side refrigerant pressure through the high side A/C refrigerant pressure sensor. The engine control module supplies a 5 V reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the sensor signal to the engine control module to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low. When pressure is high, the engine control module commands the cooling fans on.

Conditions for Running the DTC

P0531

Engage Test

Compressor speed is greater than 300 RPM.

OFF Test

The compressor has been OFF for more than 20 s.

ON Test

The compressor has been ON for more than 10 s.

P0532 and P0533

Any of the conditions for setting the DTC are met for 15 s. 12 V battery system voltage is between 11 - 18 V.

Conditions for Setting the DTC

P0531

Engage Test

The A/C high side pressure sensor change over a predetermined period of time is outside of an acceptable expected amount. The expected amount of change is determined using ambient temperature, coolant temperature, vehicle speed, and fan speed.

OFF Test

The A/C high side pressure sensor value is above the acceptable threshold.

ON Test

The A/C high side pressure sensor value is below the acceptable threshold.

P0532

The engine control module detects that the A/C pressure is less than.25 V.

P0533

The engine control module detects that the A/C pressure is greater than 4.75 V.

Action Taken When the DTC Sets This is a type B DTC. Conditions for Clearing the DTC This is a type B DTC. Diagnostic Aids

A malfunction within the refrigerant system causing high pressure can cause this DTC to set.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information Special Tools

GE-48800 CoolTech A/C Recharge Machine

Circuit/System Verification

1. Vehicle in Service Mode.

2. Install the GE-48800 CoolTech A/C Recharge Machine.

3. Verify the high side pressure reading on the Air Conditioning Service Center is within 10% of the scan tool ECM A/C High Side Pressure Sensor parameter.

If the reading is not within 10%

Refer to Circuit/System Testing.

If the reading is within 10%

4. Refer to Air Conditioning (A/C) System Performance Test .

Circuit/System Testing

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B1 A/C Refrigerant Pressure Sensor. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 5 Ω between the low reference circuit terminal 1 and ground.

If 5 Ω or greater

1. Vehicle OFF, disconnect the harness connectors at the K20 Engine Control Module.

2. Test for less than 2 Ω in the low reference circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K20 Engine Control Module.

If less than 5 Ω

3. Vehicle in Service Mode.

4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 2 and ground.

If less than 4.8 V

1. Vehicle OFF, disconnect the harness connectors at the K20 Engine Control Module.

2. Test for infinite resistance between the 5 V reference circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit.

If infinite resistance

3. Test for less than 2 Ω in the 5 V reference circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K20 Engine Control Module.

If greater than 5.2 V

1. Vehicle OFF, disconnect the harness connectors at the K20 Engine Control Module, vehicle in Service Mode.

2. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit.

If less than 1 V, replace the K20 Engine Control Module.

If between 4.8 - 5.2 V

5. Verify the scan tool Engine Control Module A/C High Side Pressure Sensor parameter is less than.25 V.

If.25 V or greater

1. Vehicle OFF, disconnect the harness connectors at the K20 Engine Control Module, vehicle in Service Mode.

2. Test for less than 1 V between the signal circuit terminal 3 and ground. If 1 V or greater, repair the short to voltage on the circuit.

If less than 1 V, replace the K20 Engine Control Module.

If less than.25 V

6. Connect a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 2.

7. Verify the scan tool A/C High Side Pressure Sensor parameter is greater than 4.75 V.

If 4.75 V or less

1. Vehicle OFF, remove the jumper wire and disconnect the harness connectors at the K20 Engine Control Module.

2. Test for infinite resistance between the signal circuit terminal 3 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance

3. Test for less than 2 Ω in the signal circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit. If less than 2 Ω, replace the K20 Engine Control Module.

If greater than 4.75 V

8. Test or replace the B1 A/C Refrigerant Pressure Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup

DTC P0534: AIR CONDITIONING (A/C) REFRIGERANT CHARGE LOW

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0534

Air Conditioning (A/C) Refrigerant Charge Low

Circuit/System Description

The AC compressor function is to provide refrigerant flow in the AC refrigerant loop to help cool down and dehumidify the cabin and help maintain the battery temperature. Rather than a more-typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes High Voltage direct current from the vehicle's High Voltage Battery and inverts it to alternating current for the motor. The AC compressor may be activated when any of the following events occur:

The customer selects ECO or MAX.

The HVAC system is fan only but the customer selects defrost mode

The High Voltage Battery Thermal System requests the AC compressor on to help maintain the battery temperature

The Hybrid Powertrain control module 2 (HPCM2) uses values from the A/C refrigerant pressure transducers, ambient air temperature sensor, cabin climate control request, battery cell temperature sensors, battery coolant temperature sensors and battery coolant pumps to determine the speed at which the compressor will operate. This message is sent from the HPCM2 to the A/C compressor control module via serial data message.

Conditions for Running the DTC

DTC P0534 Case 1

The 12V battery system voltage is equal to or greater than 10.2 V. The AC compressor has been off for more than 60 min.

The AC compressor is commanded on and operating above 500 RPM

The following DTCs must not be set: P0071, P0072, P0073. P0074, P0606, P151C, P2516, P2517, P2518

DTC P0534 Case 2

The 12V battery system voltage is equal to or greater than 10.2 V. The AC compressor is off for more than 60 min.

Outside air temperature is greater than 15° C (59°F).

The following DTCs must not be set: P0071, P0072, P0073. P0074, P0606, P151C, P2516, P2517, P2518

DTC P0534 Case 3

The 12V battery system voltage is equal to or greater than 10.2 V. The AC compressor is off for more than 60 min.

Outside air temperature is greater than 5° C (41°F).

The following DTCs must not be set: P0071, P0072, P0073. P0074, P0606, P151C, P2516, P2517, P2518

Conditions for Setting the DTC

DTC P0534 Case 1

Low side pressure is less than 90 kPa (13.05 PSI) within 60 sec of the compressor turning on

DTC P0534 Case 2

Low side pressure is less than 150 kPa (21.75 PSI) for outside air temperature greater than 20° C (68°F).

DTC P0534 Case 3

Low side pressure is less than 100 kPa (14.50 PSI) for outside air temperature between 5 - 20° C (41 - 68° F).

Action Taken When the DTC Sets

Active cooling mode for the battery may be disabled.

Conditions for Clearing the DTC P0534 is a type B DTC. Reference Information Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Install the appropriate air conditioning service center, vehicle in Service Mode.

2. Verify the low side pressure reading on the Air Conditioning Service Center is within 3% of the scan tool A/C Low Side Pressure Sensor parameter.

If the reading is not within 3%

Refer to DTC P151C or P2516-P2518.

If the reading is within 3%

3. Verify the high side pressure reading on the Air Conditioning Service Center is within 3% of the scan tool A/C High Side Pressure Sensor parameter.

If the reading is not within 3%

Refer to DTC P0531, P0532, or P0533.

If the reading is within 3%

4. Verify the A/C System is operating correctly, refer to Air Conditioning (A/C) System Performance Test

.

5. Clear all codes in the K114B Hybrid Powertrain Control Module 2 using a scan tool.

6. Verify DTC P0534 does not set while operating the HVAC system under the Conditions for Running the DTC.

If the DTC is set

Replace the K114B Hybrid Powertrain Control Module 2.

If the DTC is not set

7. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup.

DTC P0D69-P0D7F: A/C COMPRESSOR MOTOR VOLTAGE SENSOR AND ELECTRIC A/C COMPRESSOR CONTROL MODULE

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0D69

A/C Compressor Motor Voltage Sensor Performance

DTC P0D6A

A/C Compressor Motor Voltage Sensor Circuit High Voltage

DTC P0D6B

A/C Compressor Motor Voltage Sensor Circuit Low Voltage

DTC P0D71

Electric A/C Compressor Control Module Internal Temperature Sensor Performance

DTC P0D72

Electric A/C Compressor Control Module Internal Temperature Sensor Circuit High Voltage

DTC P0D73

Electric A/C Compressor Control Module Internal Temperature Sensor Circuit Low Voltage

DTC P0D76

Electric A/C Compressor Control Module Output Driver Temperature Sensor Performance

DTC P0D77

Electric A/C Compressor Control Module Output Driver Temperature Sensor Circuit High Voltage

DTC P0D78

Electric A/C Compressor Control Module Output Driver Temperature Sensor Circuit Low Voltage

Circuit/System Description

The AC compressor function is to provide refrigerant flow in the AC refrigerant loop to help cool down the cabin, help dehumidify the air in a defrost mode and help maintain the battery temperature. Rather than a more- typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes High Voltage direct current from the vehicle's High Voltage Battery and inverts it to alternating current for the motor. The AC compressor shall be activated when any of the three following events occur:

The customer pushes the AC button

The HVAC control, in AUTO mode, requests the electric AC compressor on to help in cooling the cabin or removing moisture in the defrost mode

The High Voltage Battery Thermal System requests the AC compressor on to help maintain the battery temperature

The Hybrid Powertrain control module 2 uses values from the A/C refrigerant pressure transducers, A/C refrigerant thermistor, duct temperature sensors, ambient air temperature sensor, passenger compartment temperature sensor, battery cell temperature sensors, battery coolant temperature sensors and battery coolant pumps to determine the speed at which the compressor will operate. This speed request message is sent from the Hybrid/EV Powertrain Control Module 2 to the A/C compressor control module via serial data message.

Conditions for Running the DTC

DTC P0D69

12 V battery system voltage is greater than 10.2 V. Main HV battery contactors must be closed.

DTCs P0AA4, P0ABB, P0ABC, P0ABD, P0AD9, P0C78, P0D5E, P0D6A; P0D6B, P1EC3, P2534,

P2535, P3061, U0111, U016B, or U185A must not be set.

DTC P0D6A

12 V battery system voltage is above 10.2 V. Main HV battery contactors must be closed.

DTCs P2534, P2535, P3061, or U016B must not be set.

DTC P0D6B

12 V battery system voltage is above 10.2 V. Main HV battery contactors must be closed.

DTCs P0AA4, P0AD9, P0C78, P0D5E, P1EC3, P2534, P2535, P3061, or U016B must not be set.

DTC P0D71 or P0D76

12 V battery system voltage is above 10.2 V. Vehicle is in Run Mode or Charging Mode

Compressor has been off for more than 2 hours

Outside air temperature is greater than -7°C (19°F)

DTCs P0071, P0072, P0073, P0074, P0D72, P0D73, P0D77, P0D78, P2534, P2535, or U016B must not

be set

DTC P0D72, P0D73, P0D77, or P0D78

12 V battery system voltage is above 10.2 V.

DTCs P2534, P2535, or U016B must not be set

Conditions for Setting the DTC

DTC P0D69

A/C compressor motor voltage is greater than 30 V.

DTC P0D6A

The A/C compressor high voltage input sensor value is greater than 527.25 V for 1 second.

DTC P0D6B

The A/C compressor high voltage input sensor value is less than 27.75 V for 1 second.

DTC P0D71

The A/C compressor processor temperature sensor value is greater than 22°C (72°F). AND

The difference between the A/C compressor processor temperature sensor value and the outside air temperature value is greater than 22°C (72°F).

DTC P0D72

A/C compressor processor temperature sensor value is less than -40°C (-40°F) for 6 seconds.

DTC P0D73

A/C compressor processor temperature sensor value is greater than 150°C (302°F) for 6 seconds.

DTC P0D76

The A/C compressor temperature sensor value is greater than 22°C (72°F). AND

The difference between the A/C compressor temperature sensor value and the outside air temperature value is greater than 22°C (72°F).

DTC P0D77

A/C compressor temperature sensor value is less than -40°C (-40°F) for 6 seconds.

DTC P0D78

A/C compressor temperature sensor value is greater than 150°C (302°F) for 6 seconds.

Action Taken When the DTC Sets The A/C compressor is disabled. Conditions for Clearing the DTC These are all type B DTC's Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Vehicle in Service Mode.

2. Verify that DTC P0071, P0072, P0073, P0074, P0AA4, P0ABB, P0ABC, P0ABD, P0AD9, P0C78, P0D5E, P1EC3, P2534, P2535, P3061, U0111, U016B, or U185A are not set.

If any of the DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

If none of the DTCs are set

3. Verify that DTC P0D6B is not set.

If DTC P0D6B is set

Refer to Circuit/System Testing

If DTC P0D6B is not set

4. Verify that DTC P0D69, P0D6A, P0D71, P0D72, P0D73, or P0D74 are not set.

If any of the DTCs are set

1. Program the G1 A/C Compressor and the K114B Hybrid/EV Powertrain Control Module 2 with the latest software calibration.

2. Verify the DTC's do not set

If any of the DTC's set, replace the affected control module. If none of the DTC's are set

3. All OK.

If none of the DTCs are set

5. All OK.

Circuit/System Testing

NOTE: Perform Circuit/System Verification before Circuit/System Testing.

WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.

The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage.

Identify how to test for the presence of high voltage.

Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.

Failure to follow the procedures exactly as written may result in serious injury or death.

1. Vehicle OFF, disable the high voltage at the G1 A/C Compressor. Refer to High Voltage Disabling .

2. Disconnect the X5 harness connector at the A4 Hybrid/EV Battery Pack and the X2 harness connector at the G1 A/C Compressor. Refer to High Voltage Connectors .

3. Verify the inline harness connector X130 is properly connected.

4. Test for less than 2 Ω end to end between the 300-Volt Positive and Negative Cable circuit terminals listed below:

A4 Hybrid/EV Battery Pack harness connector terminal 1 X5 and G1 A/C Compressor harness connector terminal A X2.

A4 Hybrid/EV Battery Pack harness connector terminal 2 X5 and G1 A/C Compressor harness connector terminal B X2.

If 2 Ω or greater

Replace the 300-Volt Positive and Negative Cable.

If less than 2 Ω

5. Verify the F1HA G1 A/C Compressor fuse is not open. Refer to High Voltage Battery Disconnect Relay Fuse Replacement (Front - BDU) High Voltage Battery Disconnect Relay Fuse Replacement (Rear - BDU) .

If the F1HA G1 A/C Compressor fuse is open

Replace the fuse and the G1 A/C Compressor.

If the F1HA G1 A/C Compressor fuse is not open

6. Replace the G1 A/C Compressor.

7. Operate the vehicle within the conditions for running the DTC. Verify the DTC does not set.

If the DTC sets

Replace the A28 Hybrid/EV Battery Contactor Assembly.

If the DTC does not set

8. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup

DTC P151C OR P2516-P2518: AIR CONDITIONING (A/C) REFRIGERANT LOW SIDE PRESSURE SENSOR

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P151C

Air Conditioning (A/C) Refrigerant Low Side Pressure Sensor Not Plausible

DTC P2516

Air Conditioning (A/C) Refrigerant Low Side Pressure Sensor Performance

DTC P2517

Air Conditioning (A/C) Refrigerant Low Side Pressure Sensor Circuit Low Voltage

DTC P2518

Air Conditioning (A/C) Refrigerant Low Side Pressure Sensor Circuit High Voltage

Diagnostic Fault Information

Circuit/System Description

The Hybrid/EV Powertrain Control Module 2 monitors the low side refrigerant pressure through the A/C pressure sensor. The Hybrid/EV Powertrain Control Module 2 supplies a 5 V reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the sensor signal to the Hybrid/EV Powertrain Control Module 2 to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low.

Conditions for Running the DTC

P151C

Vehicle ON

12 V battery system voltage above 10.25 V.

Hybrid/EV Powertrain Control Module 2 is awake and communicating.

None of these DTCs may be active: P2517, P2518, P0073, P0072, P0071, P0119, P0118, P0117, P0116, P0531, P0532, P0533, P0606.

Outside Air Temperature raw and corrected values must have had a chance to settle out. Once this occurs these variables are assigned a status of valid. The vehicle may need to have some time driving in EV mode.

Coolant temperature must be within 15 degrees of outside air temperature. Outside Air Temperature between 0°C (32°F) and 25°C (77°F).

AC compressor must have been off for an hour since the last time the AC compressor was on. High side refrigerant pressure reading must be between 0 kPa and 675 kPa.

P2516

Vehicle ON

12 V battery system voltage above 10.25 V.

Hybrid/EV Powertrain Control Module 2 is awake and communicating.

None of these DTCs may be active: P2517, P2518, P0073, P0072, P0071, P0119, P0118, P0117, P0116, P0606.

Coolant temperature must be within 15 degrees of outside air temperature.

AC compressor must have been off for an hour since the last time the AC compressor was on.

AC compressor must be turned on for one minute. (This may require the service technician to select an HVAC mode that causes the AC compressor to run).

P2517 or P2518

Vehicle ON

12 V battery system voltage above 10.25 V.

Hybrid/EV Powertrain Control Module 2 is awake and communicating.

Conditions for Setting the DTC

DTC P151C

The A/C low side Refrigerant Pressure reading and the A/C high side Refrigerant Pressure reading differ by more than 200 kPa (29 psi).

Loss of HVAC Control Module communication

DTC P2516

The difference between the A/C low side pressure Sensor before compressor on and after compressor on changes less than 50 kPa (7 psi) over a 15 second period.

DTC P2517

The Hybrid/EV Powertrain Control Module 2 detects a short to ground or open at the A/C low side pressure sensor signal circuit.

DTC P2518

The Hybrid/EV Powertrain Control Module 2 detects a short to voltage at the A/C low side pressure sensor signal circuit.

Action Taken When the DTC Sets

These are type B DTCs. Conditions for Clearing the DTC These are type B DTCs.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Vehicle in Service Mode.

2. Verify that DTCs U0140 and U184B are not set.

If any of the DTCs are set

Refer to DTC U0100-U02FF , or DTC U184B .

If none of the DTCs are set

3. Refer to Circuit/System Testing.

Circuit/System Testing

1. Vehicle OFF, all vehicle systems OFF, scan tool disconnected, and key removed from vehicle, disconnect the harness connector at the B1C A/C Low Side Pressure Sensor. It may take up to 10 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the low reference circuit terminal 1 and ground.

If 10 Ω or greater

1. Vehicle OFF, disconnect the harness connector at the K114B Hybrid/EV Powertrain Control Module 2.

2. Test for less than 2 Ω in the low reference circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.

If less than 2 Ω, replace the K114B Hybrid/EV Powertrain Control Module 2.

If less than 10 Ω

3. Vehicle in Service Mode.

4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 2 and ground.

If less than 4.8 V

1. Vehicle OFF, disconnect the X1 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.

2. Test for infinite resistance between the terminals listed below and ground. Terminal 63

Terminal 64

If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance

3. Test for less than 2 Ω in the 5 V reference circuit terminal 63 end to end. If 2 Ω or greater, repair the open/high resistance in the circuit.

If less than 2 Ω, replace the K114B Hybrid/EV Powertrain Control Module 2.

If greater than 5.2 V

1. Vehicle OFF, disconnect the harness connector at the K114B Hybrid/EV Powertrain Control Module 2, vehicle in Service Mode.

2. Test for less than 1 V between the terminals listed below and ground. Signal circuit terminal 25

Signal circuit terminal 31 Signal circuit terminal 50

5 V reference circuit terminal 63

5 V reference circuit terminal 64

If 1 V or greater, repair the short to voltage on the circuit.

If less than 1 V, replace the K114B Hybrid/EV Powertrain Control Module 2.

If between 4.8 - 5.2 V

5. Verify the scan tool Hybrid/EV Powertrain Control Module 2 A/C Low Side Pressure Sensor parameter is less than 0.1 V.

If 0.1 V or greater

1. Vehicle OFF, disconnect the harness connector at the K114B Hybrid/EV Powertrain Control Module 2, vehicle in Service Mode.

2. Test for less than 1 V between the signal circuit terminal 3 and ground. If 1 V or greater, repair the short to voltage on the circuit.

If less than 1 V, replace the K114B Hybrid/EV Powertrain Control Module 2.

If less than 0.1 V

6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 2.

7. Verify the scan tool A/C Low Side Pressure Sensor parameter is greater than 4.8 V.

If 4.8 V or less

1. Vehicle OFF, remove the jumper wire and disconnect the X1 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.

2. Test for infinite resistance between the signal circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit.

If infinite resistance

3. Test for less than 2 Ω in the signal circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.

If less than 2 Ω, replace the K114B Hybrid/EV Powertrain Control Module 2.

If greater than 4.8 V

8. Test or replace the B1C A/C Low Side Pressure Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup

DTC P154F: ELECTRIC A/C COMPRESSOR MOTOR INPUT CURRENT- POSITIVE CONTACTOR STATE NOT PLAUSIBLE

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P154F

Electric A/C Compressor motor Input Current- Positive Contactor State Not Plausible

Circuit/System Description

The hybrid powertrain control module 2 receives serial data messages from the A/C compressor. If the electrical current reported by the compressor is not logical based on the currently commanded state, the hybrid powertrain control module 2 sets the DTC.

Conditions for Running the DTC

Vehicle ON

12 V battery system voltage above 10.2 V.

Hybrid/EV Powertrain Control Module 2 is awake and communicating.

None of these DTCs are set: P0532, P0533, P0AA4, P0ABB, P0ABC, P0ABD, P0AD9, P0C78, P0D5E, P0D6A, P0D6B, P15CA, P1EC3, P1F0A, P1F0C, P1F0D, P2534, P2535, P3061, U0111, U016B, or U185A.

The time since the high voltage contactors have been commanded opened or closed is greater than 1 s.

Hybrid/EV Powertrain Control Module 2 monitors the data from the A/C compressor every 250 ms when the above conditions are met.

Conditions for Setting the DTC

DTC P154F is a Type B DTC.

Condition 1

The high voltage battery contactors are commanded open.

Electrical current is reported via serial data from the A/C compressor.

Condition 2

The high voltage battery contactors are commanded closed. The A/C compressor is commanded OFF (0 RPM).

Electrical current is reported via serial data from the A/C compressor.

OR

The RPM reported via serial data from the A/C compressor is greater than 60 RPM.

Condition 3

The high voltage battery contactors are commanded closed. The high voltage battery is between 300 - 410 V.

The A/C compressor is commanded ON.

The RPM reported via serial data from the A/C compressor is between 1000 - 8600 RPM.

The A/C refrigerant high side pressure reported via serial data from the ECM is between 200 - 2300 kPa (29 - 334 PSI).

Electrical current reported via serial data from the A/C compressor is less than 0.2 A or greater than 27 A.

Action Taken When the DTC Sets DTC P154F is a Type B DTC. Conditions for Clearing the DTC DTC P154F is a Type B DTC. Diagnostic Aids

These DTCs may be set during a stall.

Reference Information

Schematic Reference

Hybrid/EV Controls Schematics

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Circuit/System Verification

1. Verify DTCs P0532, P0533, P0AA4, P0ABB, P0ABC, P0ABD, P0AD9, P0C78, P0D5E, P0D6A, P0D6B, P15CA, P1EC3, P1F0A, P1F0C, P1F0D, P2534, P2535, P3061, U0111, U016B, or U185A. are

not set.

If any of the DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

If none of the DTCs are set

2. Replace the G1 A/C Compressor.

3. Verify DTC P154F does not set while operating the vehicle within the Conditions for Running the DTC.

If the DTCs sets

Replace the K114B Hybrid/EV Powertrain Control Module 2.

If the DTCs does not set

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup.

DTC P156A-P156C: AIR CONDITIONING (A/C) PRESSURE

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of the diagnostic category.

DTC Descriptors

DTC P156A

Air Conditioning (A/C) Pressure Too High when A/C Off

DTC P156B

Air Conditioning (A/C) Pressure Too Low when A/C On

Diagnostic Fault Information

Circuit/System Description

The engine control module monitors the high side refrigerant pressure through the high side A/C refrigerant pressure sensor. The engine control module supplies a 5 V reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the sensor signal to the engine control module to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low. When pressure is high, the engine control module commands the cooling fans on.

If the engine control module detects the refrigerant pressure sensor signal is not logical based on the current operating conditions, the engine control module sets the DTC.

Conditions for Running the DTC

P156A

Vehicle ON

None of these DTCs are set: P0532, P0533, or U016B The compressor has been OFF for more than 20 s.

The ECM monitors the A/C high side pressure every 100 ms when the above conditions are met.

P156B

Vehicle ON

None of these DTCs are set: P0532, P0533, or U016B The compressor has been ON for more than 10 s.

The ECM monitors the A/C high side pressure every 100 ms when the above conditions are met.

Conditions for Running the DTC

P156A

P156A is a type B DTC

The ECM detects the A/C high side pressure is too high based on the current operating conditions.

P156B

P156B is a type B DTC

The ECM detects the A/C high side pressure is too low based on the current operating conditions.

Action Taken When the DTC Sets P156A and P156B are type B DTCs Conditions for Clearing the DTC P156A and P156B are type B DTCs Diagnostic Aids

A malfunction within the refrigerant system causing can cause these DTCs to set.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information Special Tools

GE-48800 CoolTech A/C Recharge Machine

Circuit/System Verification

1. Vehicle in Service Mode.

2. Verify no other DTCs are set.

If any other DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

If no other DTCs are set

3. Install the appropriate Air Conditioning Service Center.

4. Verify the high side pressure reading on the Air Conditioning Service Center is within 10% of the scan tool ECM A/C High Side Pressure Sensor parameter.

If the reading is not within 10%

Refer to DTC P0531, P0532, or P0533.

If the reading is within 10%

5. Refer to Air Conditioning (A/C) System Performance Test .

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

DTC P15C6 OR P15C8-P15CB: ELECTRIC A/C COMPRESSOR

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for a overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P15C6

Electric A/C Compressor Speed Request Signal Message Counter Incorrect

DTC P15C8

Electric A/C Compressor Data Message Counter Incorrect

DTC P15C9

Electric A/C Compressor Status Message Counter Incorrect

DTC P15CA

Electric A/C Compressor Sensors Signal Message Counter Incorrect

DTC P15CB

Electric A/C Compressor Sensors Status Message Counter Incorrect

Circuit/System Description

The hybrid powertrain control module 2 receives serial data messages from the A/C compressor. If the message counter from the A/C compressor is not incrementing based on the currently commanded state, the hybrid

powertrain control module 2 sets the DTC.

Conditions for Running the DTC

Vehicle ON

12 V battery system voltage above 10.2 V.

Hybrid/EV Powertrain Control Module 2 is awake and communicating. None of these DTCs are set: P2534, P2535, or U016B

The A/C compressor is active.

Hybrid/EV Powertrain Control Module 2 monitors the data from the A/C compressor every 100 ms when the above conditions are met.

Conditions for Setting the DTC

The hybrid powertrain control module 2 detects the message counter from the A/C compressor is not being updated.

Action Taken When the DTC Sets

DTCs P15C6, P15C8, P15C9, P15CA, and P15CB are Type B DTCs.

Conditions for Clearing the DTC

DTCs P15C6, P15C8, P15C9, P15CA, and P15CB are Type B DTCs.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Hybrid/EV Cooling System Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Verify DTCs P2534, P2535, or U016B are not set.

If DTC P2534, P2535, or U016B are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

If DTC P2534, P2535, or U016B are not set

2. Replace the G1 A/C Compressor.

3. Verify DTCs P15C6, P15C8, P15C9, P15CA, or P15CB do not set while operating the vehicle within the Conditions for Running the DTC.

If any of the DTCs are set

Replace the K114B Hybrid/EV Powertrain Control Module 2.

If none of the DTCs are set

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup.

DTC P1F0A-P1F0D: A/C COMPRESSOR MOTOR AND ELECTRIC A/C COMPRESSOR CONTROL MODULE

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P1F0A

A/C Compressor Motor Speed Performance

DTC P1F0B

A/C Compressor Motor Start-Up Current Performance

DTC P1F0C

Electric A/C Compressor Control Module A/C Compressor Motor Current Feedback Circuit Low Voltage

DTC P1F0D

Electric A/C Compressor Control Module A/C Compressor Motor Current Feedback Circuit High Voltage

Circuit/System Description

The A/C compressor function is to provide refrigerant flow in the A/C refrigerant loop to help cool down the cabin, help dehumidify the air in a defrost mode and help maintain the battery temperature. Rather than a more- typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes High Voltage direct current from the vehicle's High voltage battery and inverts it to alternating current for the motor. The A/C compressor shall be activated when any of the three following events occur:

The customer pushes the AC button

The HVAC control, in AUTO mode, requests the electric A/C compressor on to help in cooling the cabin or removing moisture in the defrost mode

The High Voltage Battery Thermal System requests the A/C compressor on to help maintain the battery temperature

The Hybrid/EV powertrain control module 2 uses values from the A/C refrigerant pressure transducers, A/C refrigerant thermistor, duct temperature sensors, ambient air temperature sensor, passenger compartment temperature sensor, battery cell temperature sensors, battery coolant temperature sensors and battery coolant pumps to determine the speed at which the compressor will operate. This message is sent from the Hybrid/EV powertrain control module 2 to the A/C compressor control module via serial data message.

A/C Compressor has a motor start up procedure that can take a variable length of time to run to bring the motor up to requested speed. Length of time is dependent on external conditions such as underhood temperature and high side pressure. In hotter conditions, the motor start up time will be longer. The A/C compressor control module monitors an internal parameter known as the DC link current which is based off DC input current. It is not possible to measure this parameter externally.

Conditions for Running the DTC

DTC P1F0A

12 V battery system voltage is above 10.25 V. Vehicle is in Run Mode or Charging Mode

Compressor is in start up mode

DTC P1F0B

12 V battery system voltage is above 10.25 V. Vehicle is in Run Mode or Charging Mode

Compressor is in start up mode

DTC P1F0C

12 V battery system voltage is above 10.25 V. Vehicle is in Run Mode or Charging Mode

Compressor is in start up mode

DTC P1F0D

12 V battery system voltage is above 10.25 V. Vehicle is in Run Mode or Charging Mode

Compressor is in start up mode

Conditions for Setting the DTC

DTC P1F0A

A/C compressor control module temperature is greater than 85°C (185°F) and compressor motor speed does not reach to 1800 RPM within 20 s after the start of spinning

A/C compressor control module temperature is less than or equal to 85°C and A/C compressor motor speed does not reach to 1800 RPM.

DTC P1F0B

Any A/C compressor control module phase current (U/V/W) greater than or equal to -1 A during initial motor startup process

DTC P1F0C

A/C compressor control module DC link Current is less than 2.5 A for 6 s

DTC P1F0D

A/C compressor control module DC link Current is greater than 36.7 A for 6 s

Action Taken When the DTC Sets

The A/C compressor control module is disabled but will retry once the compressor speed request goes to 0 RPM and a new speed request greater than 0 RPM is sent.

Conditions for Clearing the DTC These are type B DTC's Reference Information Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Vehicle in Service Mode.

2. Verify that DTCs P1F0A-P1F0D are not set.

If any of the DTCs are set

1. Program the G1 A/C Compressor and the K114B Hybrid/EV Powertrain Control Module 2 with the latest software calibration.

2. Verify the DTCs do not set

If any of the DTCs set, replace the affected control module. If none of the DTCs are set

3. All OK.

If none of the DTCs are set

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup

DTC P15C5, P2682, P2683, P26A5-P26A7, P26A9, P26AD, OR P26AE: ENGINE COOLANT BYPASS VALVE POSITION SENSOR/ENGINE COOLANT BYPASS VALVE CONTROL CIRCUITS

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P15C5 00

Engine Coolant Bypass Valve Position Sensor Range/ Performance - Unexpected Position Change Detected

DTC P2682 00

Engine Coolant Bypass Valve Control Circuit 1 Low Voltage

DTC P2683 00

Engine Coolant Bypass Valve Control Circuit 1 High Voltage

DTC P26A5 00

Engine Coolant Bypass Valve Position Sensor Range/ Performance

DTC P26A6 00

Engine Coolant Bypass Valve Position Sensor Circuit Low Voltage

DTC P26A7 00

Engine Coolant Bypass Valve Position Sensor Circuit High Voltage

DTC P26A9 00

Engine Coolant Bypass Valve Position Sensor Stop/ Minimum Stop Performance

DTC P26AD 00

Engine Coolant Bypass Valve Control Circuit 2 Low Voltage

DTC P26AE 00

Engine Coolant Bypass Valve Control Circuit 2 High Voltage

Diagnostic Fault Information

Circuit/System Description

The passenger compartment heater coolant control valve regulates the engine coolant flow into the cabin heater loop depending on engine coolant temperature and ambient temperature conditions. The passenger compartment heater coolant control valve has two positions: ByPass or Link. In the ByPass position, the coolant in the engine loop and heater loop are separated and in the link position the coolant circulates through both loops. The valve movement is controlled by a bidirectional motor. A 50% duty cycle is a normal duty cycle. A 75% duty cycle represents a valve commanded to the link position. A 25% duty cycle represents a valve commanded to the ByPass position. The passenger compartment heater coolant control valve uses an internal position sensor that sends a signal to the hybrid powertrain control module 2 to determine the valve position.

When the engine coolant temperature heats up, a valve learn procedure takes place. The hybrid powertrain control module 2 commands the valve to the link position and records the voltage coming back from the position sensor. Then the hybrid powertrain control module 2 commands the valve back to the bypass position and records the voltage coming back from the position sensor. The voltage values in both the link and bypass positions must fall within calibrated ranges.

Conditions for Running the DTC

P15C5

12 V battery system voltage is greater than or equal to 10.2 V. The propulsion system is active.

None of the following DTCs are set: P2682, P2683, P26A5, P26A6, P26A7, P26A9, P26AD, or P26AE. The valve control command is stop.

P2682

12 V battery system voltage is greater than 10.2 V. The valve control 1 command is low.

P2683

12 V battery system voltage is greater than 10.2 V. The valve control 1 command is high or stop.

P26A5

12 V battery system voltage is greater than or equal to 10.2 V. The propulsion system is active.

None of the following DTCs are set: P2682, P2683, P26A6, P26A7, P26AD, or P26AE.

The valve control command is stop.

P26A6 and P26A7

12 V battery system voltage is greater than 10.2 V.

P26A9

12 V battery system voltage is greater than 10.2 V. The propulsion system is active.

None of the following DTCs are set; P0116, P0117, P0118, P0119, P2682, P2683, P26A6, P26A7, P26AD, P26AE.

The coolant temperature is above 58°C(136°F).

P26AD

12 V battery system voltage is greater than 10.2 V. The valve control 2 command is low.

P26AE

12 V battery system voltage is greater than 10.2 V. The valve control 2 command is high or stop.

Conditions for Setting the DTC

P15C5

The hybrid powertrain control module 2 has detected the valve feedback has drifted out of the commanded position when the valve command is stop.

P2682

The hybrid powertrain control module 2 has detected a short to ground on the valve drive 1 circuit.

P2683

The hybrid powertrain control module 2 has detected a short to voltage or an open on the valve drive 1 circuit.

P26A5

The hybrid powertrain control module 2 has detected the valve feedback has exceeded the valid range.

P26A6

The hybrid powertrain control module 2 has detected a short to ground on feedback circuit. The feedback signal is less than 5% (0.25 V).

P26A7

The hybrid powertrain control module 2 has detected a short to voltage on feedback circuit. The feedback signal

is greater than 95% (4.25 V).

P26A9

The valve has not reached the commanded position, valve position relearn was attempted and the valve still does not reach the commanded position.

OR

An open circuit condition exists on either of the valve control circuits.

P26AD

The hybrid powertrain control module 2 has detected a short to ground on the valve drive 2 circuit.

P26AE

The hybrid powertrain control module 2 has detected a short to voltage or an open on the valve drive 2 circuit.

Action Taken When the DTC Sets

DTCs P15C5, P2682, P2683, P26A5, P26A6, P26A7 P26A9, P26AD, and P26AD are type B DTCs.

Conditions for Clearing the DTC

DTCs P15C5, P2682, P2683, P26A5, P26A6, P26A7 P26A9, P26AD, and P26AD are type B DTCs.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Vehicle in Service Mode.

2. Verify that DTC P0116, P0117, P0118, or P0119 is not set.

If any of the DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

If none of the DTCs are set

3. Refer to Circuit/System testing.

Circuit/System Testing

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the Q66 Passenger Compartment Heater Coolant Control Valve. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 5 Ω between the low reference circuit terminal 5 and ground.

If 5 Ω or greater

1. Disconnect the X1 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.

2. Test for less than 2 Ω in the low reference circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.

If less than 2 Ω, replace the K114B Hybrid/EV Powertrain Control Module 2.

If less than 5 Ω

3. Vehicle in Service Mode.

4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 6 and ground.

If less than 4.8 V

1. Vehicle OFF, disconnect the X1 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.

2. Test for infinite resistance between the 5 V reference circuit and ground.

If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance

3. Test for less than 2 Ω in the 5 V reference circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.

If less than 2 Ω, replace the K114B Hybrid/EV Powertrain Control Module 2.

If greater than 5.2 V

1. Vehicle OFF, disconnect the X1 harness connector at the K114B Hybrid/EV Powertrain Control Module 2, vehicle in Service Mode.

2. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit.

If less than 1 V, replace the K114B Hybrid/EV Powertrain Control Module 2.

If between 4.8 - 5.2 V

5. Verify the scan tool Hybrid Powertrain Control Module 2, Passenger Compartment Heater Coolant Control Solenoid Valve Feedback parameter is greater than 95%.

If less than 95%

1. Vehicle OFF, disconnect the X1 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.

2. Test for infinite resistance between the signal circuit terminal 50 and ground. If less than infinite resistance, repair the short to ground on the circuit.

If infinite resistance, replace the K114B Hybrid/EV Powertrain Control Module 2.

If greater than 95%

6. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 5.

7. Verify the scan tool Passenger Compartment Heater Coolant Control Solenoid Valve Feedback parameter is less than 10%.

If 10% or greater

1. Vehicle OFF, remove the jumper wire and disconnect the X1 harness connector at the K114B Hybrid/EV Powertrain Control Module 2, vehicle in Service Mode.

2. Test for less than 1 V between the signal circuit terminal 50 and ground. If 1 V or greater, repair the short to voltage on the circuit.

If less than 1 V

3. Vehicle OFF.

4. Test for less than 2 Ω in the signal circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.

If less than 2 Ω, replace the K114B Hybrid/EV Powertrain Control Module 2.

If less than 10%

8. Vehicle OFF, remove the jumper wire.

9. Disconnect the X2 harness connector at the K114B Hybrid/EV Powertrain Control Module 2, vehicle in Service Mode.

10. Test for less than 1 V between each control circuit listed below and ground: Q66 Passenger Compartment Heater Coolant Control Valve terminal 1 Q66 Passenger Compartment Heater Coolant Control Valve terminal 2 If 1 V or greater

Repair the short to voltage on the circuit.

If less than 1 V

11. Vehicle OFF.

12. Test for infinite resistance between each control circuit listed below and ground: Q66 Passenger Compartment Heater Coolant Control Valve terminal 1

Q66 Passenger Compartment Heater Coolant Control Valve terminal 2

If less than infinite resistance

Repair the short to ground on the circuit.

If infinite resistance

13. Test for less than 2 Ω in each control circuit end to end.

If 2 Ω or greater

Repair the open/high resistance in the circuit.

If less than 2 Ω

14. Replace the Q66 Passenger Compartment Heater Coolant Control Valve.

15. Verify the DTC does not set while operating the vehicle under the Conditions for Running the DTC.

If the DTC sets

Replace the K114B Hybrid/EV Powertrain Control Module 2.

If the DTC does not set

16. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for the control module replacement, programming and setup.

SYMPTOMS - HVAC SYSTEMS - AUTOMATIC

NOTE: The following steps must be completed before using the symptom tables:

1. Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in order to verify that all of the following are true:

There are no DTCs set.

The control modules can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions. Refer to

Automatic HVAC Description and Operation.

Visual/Physical Inspection

Inspect for aftermarket devices which may affect the operation of the HVAC System. Refer to Checking Aftermarket Accessories .

Inspect the easily accessible or visible system components for obvious damage or conditions which may cause the symptom.

Verify the A/C compressor turns freely and is not seized.

Verify that the customer is using the correct key to enable personalization and is not inadvertently

activating auxiliary HVAC controls.

The A/C compressor will not operate in cold outside air temperatures. The following conditions may cause window fogging:

Wet carpet or mats High humidity

Interior water leak

Blocked A/C evaporator drain tube Maximum passenger capacity

Blocked body pressure relief valves

Inspect the air distribution system for causes of reduced air flow:

Obstructed or dirty passenger compartment air filter, if equipped Blocked or damaged air inlet or outlet vents

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

HVAC System Malfunction

HVAC SYSTEM MALFUNCTION

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Aids

Check the following mechanical fault sources: Air distribution box

Air distribution hoses/air distribution ducts

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: Check for bulletins before proceeding.

1. Vehicle in Service Mode.

2. Verify every applicable scan tool switch parameter changes when pressing the appropriate switch on the A26 HVAC Controls.

If any parameter does not change

Replace the A26 HVAC Controls.

If all parameters change

3. Verify the blower motor operates properly with the blower motor switch in each speed position.

If the blower motor does not operate properly in each speed position

Refer to DTC B0193.

If the blower motor operates properly in each speed position

4. Verify every HVAC door moves correctly when pressing the appropriate switch.

If any HVAC door does not move correctly

Refer to DTC B0223, B0233, B023A, or B0408.

If all HVAC doors move correctly

5. Install the appropriate ACR Air Conditioning Service Center, Vehicle in Service Mode

6. Verify the high side pressure on the gauge is within 10% of the scan tool A/C High Side Pressure Sensor parameter.

If the A/C High Side Pressure Sensor parameter is not within 10%

Refer to DTC P0531, P0532, or P0533.

If the A/C High Side Pressure Sensor parameter is within 10%

7. Verify the A/C High Side Pressure Sensor parameter is between 269-2929 kPa (39-425 PSI).

If the reading is not between 269-2929 kPa (39-425 PSI)

Refer to Air Conditioning (A/C) System Performance Test

If the reading is between 269-2929 kPa (39-425 PSI)

8. Verify the low side pressure on the gauge is within 10% of the scan tool A/C Low Side Pressure Sensor parameter.

If the A/C Low Side Pressure Sensor parameter is not within 10%

Refer to DTC P151C or P2516-P2518.

If the A/C Low Side Pressure Sensor parameter is within 10%

9. Verify the scan tool parameters listed below are within 10% of ambient temperature. Lower Left Duct Air Temperature Sensor

Upper Left Duct Air Temperature Sensor

If not within 10% of ambient temperature

Refer to DTC B0173 or B0178.

If within 10% of ambient temperature

10. Verify the scan tool Sunload parameter changes while covering the B10B Ambient Light/Sunload Sensor with a shop towel or other suitable item.

If the Sunload parameter does not change

Refer to DTC B0183.

If the Sunload parameter changes

11. Verify the actual inside air temperature, using a thermometer, is less than 3°C (5°F) difference from the scan tool Inside Passenger Compartment Air Temp. Sensor parameter.

If greater than a 3°C (5°F) difference

Refer to DTC B0163.

If less than a 3°C (5°F) difference

12. Verify the scan tool parameters listed below are within 10% of actual conditions. Passenger Compartment Humidity

Passenger Compartment Humidity Sensor Temperature Passenger Compartment Windshield Temperature

If not within 10% of actual conditions

Refer to DTC B018A, B048C, B048F, or B1395.

If within 10% of actual conditions

13. Vehicle ON, A/C system ON.

14. Verify cool air flows from the ducts with the temperature control in the coldest position.

If the air is not cool

Refer to Air Conditioning (A/C) System Performance Test

If the air is cool

15. Engine OFF, Vehicle in Service Mode.

16. Verify the G36 Auxiliary Heater Coolant Pump turns On and Off when commanded with a scan tool.

If the G36 Auxiliary Heater Coolant Pump does not turn On and Off

Refer to DTC B3844.

If the G36 Auxiliary Heater Coolant Pump turns On and Off

17. Vehicle ON, verify the K10 Coolant Heater Control Module is operating properly.

If the K10 Coolant Heater Control Module is not operating properly

Refer to DTC B048E

If the K10 Coolant Heater Control Module is operating properly

18. Verify warm air flows from the ducts with the temperature control in the warmest position.

If the air is not warm

Refer to Heating Performance Diagnostic .

If the air is warm

19. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference

Control Module References for control module replacement, programming and setup

AUXILIARY HEATER COOLANT PUMP MALFUNCTION

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B3844 01

Engine Coolant Circulation Pump Circuit Short to Battery

DTC B3844 06

Engine Coolant Circulation Pump Circuit Low Voltage/Open

Diagnostic Fault Information

Circuit/System Description

The coolant heater pump is controlled by a relay. When operating conditions exist that requires coolant flow when the engine is not operating, the HVAC control module turns ON the heater coolant pump by applying ground to the relay control circuit which energizes the heater coolant pump relay.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Vehicle in Service Mode.

2. Verify the G36 Auxiliary Heater Coolant Pump operates when commanding the Auxiliary Coolant Pump Relay On and Off with a scan tool.

If the G36 Auxiliary Heater Coolant Pump does not operate

Refer to DTC B3844.

If the G36 Auxiliary Heater Coolant Pump operates

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

AFTERBLOW ENABLING

Afterblow is a feature that dries the evaporator core by operating the blower motor after the engine is turned off. This aids in reducing microbial growth that can create undesirable odors.

The vehicle does not come equipped with the afterblow feature turned on. If the afterblow feature is required due to an odor concern, it must be enabled by using the scan tool.

Use the following procedure to enable the afterblow feature:

1. Connect the Scan Tool.

2. Ignition ON/ Vehicle in Service Mode

3. Select Module Diagnostics.

4. Select HVAC Control Module.

5. Select Configuration/Reset Functions.

6. Select HVAC Afterblow Configuration.

When afterblow has been enabled, the following conditions must be met for the HVAC control module to operate afterblow:

The vehicle must be turned OFF.

The outside air temperature must be at least 11°C (52°F) when the compressor was last operating before the engine was turned OFF.

The A/C compressor must have operated for more than 2 minutes before the engine was turned OFF. The system voltage must be above 12 V.

Once the above conditions have been met, the blower motor will operate at a low blower speed, following the sequence below up to 5 times:

1. The blower motor will be OFF for 7 - 11 minutes.

2. The blower motor will operate for 20 - 60 seconds.

ACTUATOR RECALIBRATION

NOTE: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.

When replacing the HVAC control module it will be necessary to allow the HVAC control module to perform a calibration process. When installing the HVAC control module be sure to perform the following:

1. Place the ignition switch to the OFF position.

2. Disconnect the scan tool.

3. Install the HVAC control module.

4. Connect all previously disconnected components.

5. Vehicle in Service Mode.

6. Wait 40 seconds for the HVAC control module to self-calibrate.

7. Verify that no DTCs have set as current DTCs.

When replacing the HVAC actuator it will be necessary to allow the HVAC control module to perform a calibration process. When installing the HVAC actuator be sure to perform one of the following:

Preferred Method (with Scan Tool)

NOTE: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.

1. Clear all DTCs.

2. Place the ignition switch in the OFF position.

3. Install the HVAC actuator.

4. Connect all previously disconnected components.

5. Start the vehicle.

6. With the scan tool, initiate the HVAC Actuators re-calibration feature of the Remote Heater and Air Conditioning Control Module Special Functions menu.

7. Verify that no DTCs have set as current DTCs.

Alternate Method (without Scan Tool)

NOTE: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.

1. Clear all DTCs.

2. Place the ignition switch to the OFF position.

3. Install the HVAC actuator.

4. Connect all previously disconnected components.

5. Remove the HVAC control module fuse for a minimum of 10 seconds.

6. Install the HVAC control module fuse.

7. Vehicle in Service Mode.

8. Wait 40 seconds for the HVAC control module to self-calibrate.

9. Verify that no DTCs have set as current DTCs.

REPAIR INSTRUCTIONS

WIRE TO WIRE REPAIR - HVAC

Special Tools

EL-38125-10 Splice Sleeve Crimping Tool (non GMNA)

J-38125-5A Ultra Torch Special Tool

J-38125-8 Splice Sleeve Crimping Tool (GMNA)

For equivalent regional tools, refer to Special Tools .

WARNING: In order to reduce the risk of personal injury, loss of high voltage isolation to ground and higher system impedance, do not attempt to repair any HV wiring, connector, or terminal that is damaged. High voltage coaxial type cables are not repairable. Never attempt to repair a coaxial type cable. The entire cable/harness or component must be replaced. In order to maintain system integrity and personal safety, never attempt to repair any high voltage wiring, cables, or terminals. Performing this procedure on high voltage circuits may result in serious injury or death.

NOTE: If the wiring harness internal to the transmission is damaged, the wiring harness must be replaced. The use of splice sleeves in an attempt to repair the internal transmission wires, connectors, or terminals could result in performance issues.

NOTE: Do not splice wires in Door Harness Grommets.

NOTE: The DuraSeal splice sleeves have the following 2 critical features:

A special heat shrink sleeve environmentally seals the splice. The heat shrink sleeve contains a sealing adhesive inside.

A cross hatched (knurled) core crimp provides the necessary low resistance contact integrity for these sensitive, low energy circuits.

Use only DuraSeal splice sleeves to form a one-to-one splice on all types of insulation except high voltage and specialty cables. Use DuraSeal splice sleeves where there are special requirements such as moisture sealing.

Follow the instructions below in order to splice copper wire using DuraSeal splice sleeves.

Splice Sleeve Selection

NOTE: You must perform the following procedures in the listed order. Repeat the procedure if any wire strands are damaged. You must obtain a clean strip with all of the wire strands intact.

1. Open the harness by removing any tape:

Use a sewing seam ripper, available from sewing supply stores, in order to cut open the harness in order to avoid wire insulation damage.

Use the DuraSeal splice sleeves on all types of insulation except Tefzel and coaxial.

Do not use the crimp and DuraSeal splice sleeve to form a splice with more than 2 wires coming together.

2. Cut as little wire off the harness as possible. You may need the extra length of wire in order to change the location of a splice.

Adjust splice locations so that each splice is at least 40 mm (1.5 in) away from the other splices, harness branches, or connectors.

3. Strip the insulation:

When adding a length of wire to the existing harness, use the same size wire as the original wire. Perform one of the following items in order to find the correct wire size:

Find the wire on the schematic and convert to regional wiring gauge size.

If you are unsure of the wire size, begin with the largest opening in the wire stripper and work down until achieving a clean strip of the insulation.

Strip approximately 5.0 mm (0.20 in) of insulation from each wire to be spliced.

Do not nick or cut any of the strands. Inspect the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section.

4. For high temperature wiring, slide a section of high temperature SCT1 shrink tubing down the length of wire to be spliced. Ensure that the shrink tubing will not interfere with the splice procedure.

5. Select the proper DuraSeal splice sleeve according to the wire size. Refer to the above table at the beginning of the repair procedure for the color coding of the DuraSeal splice sleeves and the crimp tool nests.

Fig. 6: Splice Sleeve Crimping Tool With 4 Crimp Nests Courtesy of GENERAL MOTORS COMPANY

6. The EL-38125-10 splice sleeve crimping tool has four crimp nests. The largest crimp nest (4) is used for crimping 10 and 12 gauge wires. The second largest crimp nest (3) is used for crimping 14 and 16 gauge wires. The third largest crimp nest (2) is used for crimping 18 and 20 gauge wires. The smallest crimp nest (1) is used for crimping 22 to 26 gauge wires. The crimp nests are referenced in the table (farther above) under the crimp tool nest color.

Fig. 7: Splice Sleeve Crimping Tool With 3 Crimp Nests Courtesy of GENERAL MOTORS COMPANY

7. The J-38125-8 splice sleeve crimping tool has three crimp nests. The largest crimp nest (3) is used for crimping 10 and 12 gauge wires. The second largest crimp nest (2) is used for crimping 14 and 16 gauge wires. The smallest crimp nest (1) is used for crimping 18 to 20 gauge wires. The crimp nests are referenced in the table (farther above) under the crimp tool nest color.

8. Use the splice sleeve crimp tool in order to position the DuraSeal splice sleeve in the proper color nest of the splice sleeve crimp tool. For the four crimp nest tool, use the three largest crimp nests to crimp the splice sleeves. For the three crimp nest tool, use all three crimp nests to crimp the splice sleeves. Use the four and three crimp tool diagrams (above) and the table (farther above) to match the splice sleeve with the correct crimp nest. The crimp tool diagram callout numbers match the numbers in the table (under crimp tool nest color).

Fig. 8: Identifying Duraseal Splice Sleeve Courtesy of GENERAL MOTORS COMPANY

9. Place the DuraSeal splice sleeve in the nest. Ensure that the crimp falls midway between the end of the barrel and the stop. The sleeve has a stop (3) in the middle of the barrel (2) in order to prevent the wire (1) from going further. Close the hand crimper handles slightly in order to firmly hold the DuraSeal splice sleeve in the proper nest.

Fig. 9: Crimped Duraseal Splice Sleeve Courtesy of GENERAL MOTORS COMPANY

10. Insert the wire into the splice sleeve barrel until the wire hits the barrel stop. Refer to Folded-Over Wire Repair for splicing wires of 0.35 mm or less (22, 24, 26 gauge sizes) and for splicing wires of different gauges.

11. Tightly close the handles of the crimp tool until the crimper handles open when released.

The crimper handles will not open until you apply the proper amount of pressure to the DuraSeal splice sleeve. Repeat steps 4 and 6 for the opposite end of the splice.

Fig. 10: Crimped Duraseal Splice Sleeve Courtesy of GENERAL MOTORS COMPANY

12. Using the heat torch, apply heat to the crimped area of the barrel.

13. Start in the middle and gradually move the heat barrel to the open ends of the tubing: The tubing will shrink completely as the heat is moved along the insulation.

A small amount of sealant will come out of the end of the tubing when sufficient shrinkage is achieved.

Weatherpack™ Wiring Repair

NOTE: Some replacement pigtail connectors may be delivered without the terminated leads installed into the connector. For Weatherpack™ connectors, all terminated leads included in the package should to be installed into the connector. If the connector end view shows that a terminal is not occupied, the extra terminated lead(s) need to be installed and the end(s) sealed using a DuraSeal splice sleeve and taped back into the harness.

1. Insert the wire into the splice sleeve barrel until the wire hits the barrel stop. Refer to Folded-Over Wire Repair for splicing wires of 0.35 mm or less (22, 24, 26 gauge sizes) and for splicing wires of different gauges.

Fig. 11: Tightly Close Handles Of Crimp Tool Courtesy of GENERAL MOTORS COMPANY

2. Tightly close the handles of the crimp tool until the crimper handles open when released.

The crimper handles will not open until you apply the proper amount of pressure to the DuraSeal splice sleeve. Holding the DuraSEAL with one hand gently tug on the wire to ensure it is crimped in the DuraSeal.

3. Using the heat torch, apply heat to the crimped area of the barrel.

Fig. 12: Heat To Crimped Area Of Barrel Courtesy of GENERAL MOTORS COMPANY

4. Start in the middle and gradually move the heat barrel to the open ends of the tubing: The tubing will shrink completely as the heat is moved along the insulation.

A small amount of sealant will come out of the end of the tubing when sufficient shrinkage is achieved.

Fig. 13: Taping Extra Terminated Leads Back Into Harness Courtesy of GENERAL MOTORS COMPANY

5. Tape the extra terminated lead(s) back into the harness.

High Temperature Wiring Repairs

Use the following procedures to perform high temperature wiring repairs:

1. Center the high temperature SCT1 shrink tube over the DuraSeal splice sleeve.

2. Using the heat torch, apply heat to the high temperature heat shrink tubing.

3. Gradually move the heat from the center to the open end of the tubing:

The tubing will shrink completely as the heat is moved along the insulation.

A small amount of sealant will come out of the end of the tubing when sufficient shrinkage is achieved.

4. Replace any reflective tape and clips that may have been removed during the repair.

CONNECTOR RECONNECTION - HVAC

Special Tools

EL-35616 Terminal Test Probe Kit

For equivalent regional tools, refer to Special Tools .

When the condition is not currently present, but is indicated in DTC history, the cause may be intermittent. An intermittent may also be the cause when there is a customer complaint, but the symptom cannot be duplicated. Refer to the Symptom Table of the system that is suspect of causing the condition before trying to locate an intermittent condition.

Most intermittent conditions are caused by faulty electrical connections or wiring. Inspect for the following items:

Loose, corroded, or painted terminal stud/fastener Wiring broken inside the insulation

Poor connection between the male and female terminal at a connector A terminal not seated all the way into the connector body

Poor terminal to wire connection - Some conditions which fall under this description are poor crimps, poor solder joints, crimping over the wire insulation rather than the wire itself, and corrosion in the wire to terminal contact area, etc.

Pierced or damaged insulation can allow moisture to enter the wiring causing corrosion. The conductor can corrode inside the insulation, with little visible evidence. Look for swollen and stiff sections of wire in the suspect circuits.

Wiring which has been pinched, cut, or its insulation rubbed through may cause an intermittent open or short as the bare area touches other wiring or parts of the vehicle.

Wiring that comes in contact with hot or exhaust components

Refer to Inducing Intermittent Fault Conditions in order to duplicate the conditions required, in order to verify the customer concern.

Refer to Testing for Electrical Intermittents for test procedures to detect intermittent open, high resistance, short to ground, and short to voltage conditions.

Refer to Scan Tool Snapshot Procedure for advanced intermittent diagnosis and Vehicle Data Recorder operation.

Testing for Terminal Fretting

Some intermittent conditions can be caused by wire terminal fretting corrosion. Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can pile up enough at the electrical contact spots that the electrical resistance across the connection increases. Movement between the contacting surfaces as small as 10 to 100 microns can cause fretting. To put this in perspective, a sheet of paper is about 100 microns thick, so fretting motion is small and hard to see. Vibration and thermal expansion/contraction are the main sources that create fretting motion. Since vehicles vibrate and can experience large temperature swings, they are a good source for fretting motion. Tin, copper, nickel, and iron surfaces are all susceptible to fretting corrosion. Fretting corrosion can be difficult to see but it looks like small, dark smudges on the terminals contact surface.

To correct a fretting condition disconnect the suspect connector and add dielectric grease / lubricant (Nyogel

760G or equivalent, meeting GM specification 9986087) to both sides of the connector terminals. Then reconnect the connector and wipe away any excess lubricant. This will correct the additional terminal contact resistance due to the terminal fretting corrosion.

Testing for Proper Terminal Contact

It is important to test terminal contact at the component and any inline connectors before replacing a suspect component. Mating terminals must be inspected to ensure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation.

Contamination may be caused by the connector halves being improperly connected. A missing or damaged connector seal, damage to the connector itself, or exposing the terminals to moisture and dirt can also cause contamination. Contamination, usually in the underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit.

Deformation is caused by probing the mating side of a connector terminal without the proper adapter. Always use the EL-35616 kit when probing connectors. Other causes of terminal deformation are improperly joining the connector halves, or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact causing an open or intermittently open circuit.

Testing for Proper Terminal Contact in Bussed Electrical Centers

It is very important to use the correct test adapter when testing for proper terminal contact of fuses and relays in a bussed electrical center. Use the EL-35616 kit to test for proper terminal contact. Failure to use the EL-35616 kit can result in improper diagnosis of the bussed electrical center.

Follow the procedure below in order to test terminal contact:

1. Separate the connector halves.

2. Visually inspect the connector halves for contamination. Contamination may result in a white or green build-up within the connector body or between terminals. This causes high terminal resistance, intermittent contact, or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals, and connector body.

3. Using an equivalent male terminal/terminated lead, verify that the retention force is significantly different between a known good terminal and the suspect terminal. Replace the female terminal in question.

Flat Wire Connectors

There are no serviceable parts for flat wire connectors on the harness side or the component side. Follow the procedure below in order to test terminal contact:

1. Remove the component in question.

2. Visually inspect each side of the connector for signs of contamination. Avoid touching either side of the connector as oil from your skin may be a source of contamination as well.

3. Visually inspect the terminal bearing surfaces of the flat wire circuits for splits, cracks, or other imperfections that could cause poor terminal contact. Visually inspect the component side connector to ensure that all of the terminals are uniform and free of damage or deformation.

4. Insert the appropriate adapter into the flat wire harness connector in order to test the circuit in question.

Control Module/Component Voltage and Grounds

Poor voltage or ground connections can cause widely varying symptoms.

Test all control module voltage supply circuits. Many vehicles have multiple circuits supplying voltage to a control module. Other components in the system may have separate voltage supply circuits that may also need to be tested. Inspect connections at the module/component connectors, fuses, and any intermediate connections between the voltage source and the module/component. A test lamp or a DMM may indicate that voltage is present, but neither tests the ability of the circuit to carry sufficient current.

Operate the component to test the ability of the circuit to carry sufficient current. Refer to Circuit Testing

, and Power Distribution Schematics .

Test all control module ground and system ground circuits. The control module may have multiple ground circuits. Other components in the system may have separate grounds that may also need to be tested.

Inspect grounds for clean and tight connections at the grounding point (screw or stud). Inspect the connections at the component and in splice packs, where applicable. Operate the component to test the ability of the circuit to carry sufficient current. Refer to Circuit Testing , and Ground Distribution Schematics .

Temperature Sensitivity

An intermittent condition may occur when a component/connection reaches normal operating temperature. The condition may occur only when the component/connection is cold, or only when the component/connection is hot.

Freeze Frame, Failure Records, Snapshot, or Vehicle Data Recorder data may help with this type of intermittent condition, where applicable.

If the intermittent is related to heat, review the data for a relationship with the following: High ambient temperatures

Underhood/engine generated heat

Circuit generated heat due to a poor connection, or high electrical load Higher than normal load conditions, towing, etc.

If the intermittent is related to cold, review the data for the following:

Low ambient temperatures - In extremely low temperatures, ice may form in a connection or component. Inspect for water intrusion.

The condition only occurs on a cold start.

The condition goes away when the vehicle warms up.

Information from the customer may help to determine if the trouble follows a pattern that is temperature related.

If temperature is suspected of causing an intermittent fault condition, attempt to duplicate the condition.

Refer to Inducing Intermittent Fault Conditions in order to duplicate the conditions required.

Electromagnetic Interference and Electrical Noise

Some electrical components/circuits are sensitive to electromagnetic interference or other types of electrical noise. Inspect for the following conditions:

A mis-routed harness that is too close to high voltage/high current devices such as secondary ignition

components, motors, generator etc. - These components may induce electrical noise on a circuit that could interfere with normal circuit operation.

Electrical system interference caused by a malfunctioning relay, or a control module driven solenoid or switch - These conditions can cause a sharp electrical surge. Normally, the condition will occur when the malfunctioning component is operating.

Installation of non-factory or aftermarket add on accessories such as lights, 2-way radios, amplifiers, electric motors, remote starters, alarm systems, cell phones, etc. - These accessories may create interference in other circuits while operating and the interference would disappear when the accessory is not operating. Refer to Checking Aftermarket Accessories .

Test for an open diode across the A/C compressor clutch and for other open diodes. Some relays may contain a clamping diode.

The generator may be allowing AC noise into the electrical system.

Incorrect Control Module

There are only a few situations where reprogramming a control module is appropriate: A new service control module is installed.

A control module from another vehicle is installed.

Revised software/calibration files have been released for this vehicle.

NOTE: DO NOT re-program the control module with the SAME software/calibration files that are already present in the control module. This is not an effective repair for any type of concern.

Verify that the control module contains the correct software/calibration. If incorrect programming is found, reprogram the control module with the most current software/calibration. Refer to Control Module References for replacement, setup, and programming.

HEATER AND AIR CONDITIONING USER INTERFACE CONTROL REPLACEMENT

Fig. 14: Heater And Air Conditioning User Interface Control Courtesy of GENERAL MOTORS COMPANY

HEATER AND AIR CONDITIONING REMOTE CONTROL REPLACEMENT

Fig. 15: Heater and Air Conditioning Remote Control Courtesy of GENERAL MOTORS COMPANY

AIR CONDITIONING MODULE WIRING HARNESS REPLACEMENT

Fig. 16: Air Conditioning Module Wiring Harness Courtesy of GENERAL MOTORS COMPANY

MODE VALVE LEVER REPLACEMENT

Fig. 17: Mode Valve Lever

Courtesy of GENERAL MOTORS COMPANY

VENT VALVE LEVER REPLACEMENT

Fig. 18: Vent Valve Lever

Courtesy of GENERAL MOTORS COMPANY

AIR INLET VALVE LEVER REPLACEMENT - FRONT

Fig. 19: Air Inlet Valve Lever - Front

Courtesy of GENERAL MOTORS COMPANY

AIR INLET VALVE LEVER REPLACEMENT - MIDDLE

Fig. 20: Air Inlet Valve Lever - Middle Courtesy of GENERAL MOTORS COMPANY

AIR INLET VALVE LEVER REPLACEMENT - REAR

Fig. 21: Air Inlet Valve Lever - Rear

Courtesy of GENERAL MOTORS COMPANY

AIR INLET VALVE ACTUATOR REPLACEMENT

Fig. 22: Air Inlet Valve Actuator

Courtesy of GENERAL MOTORS COMPANY

AIR INLET VALVE LINK REPLACEMENT

Fig. 23: Air Inlet Valve Link

Courtesy of GENERAL MOTORS COMPANY

MODE VALVE GEAR REPLACEMENT

Fig. 24: Mode Valve Gear

Courtesy of GENERAL MOTORS COMPANY

MODE CONTROL CAM ACTUATOR REPLACEMENT

Fig. 25: Mode Control Cam Actuator

Courtesy of GENERAL MOTORS COMPANY

MODE CONTROL CAM REPLACEMENT

Fig. 26: Mode Control Cam

Courtesy of GENERAL MOTORS COMPANY

MODE CONTROL CAM ACTUATOR MOUNTING PLATE REPLACEMENT

Removal Procedure

Fig. 27: Floor Front Air Outlet Duct - Left Side Courtesy of GENERAL MOTORS COMPANY

1. Remove Floor Front Air Outlet Duct - Left Side (2)Floor Front Air Outlet Duct Replacement - Left Side

Fig. 28: Temperature Valve Actuator

Courtesy of GENERAL MOTORS COMPANY

2. Remove Temperature Valve Actuator (2)Temperature Valve Actuator Replacement

Fig. 29: Mode Control Cam Actuator

Courtesy of GENERAL MOTORS COMPANY

3. Remove Mode Control Cam Actuator (2)Mode Control Cam Actuator Replacement

Fig. 30: Mode Control Cam Actuator Mounting Plate & Bolts Courtesy of GENERAL MOTORS COMPANY

4. Remove Mode Control Cam Actuator Mounting Plate Bolt (1)

5. Remove Mode Control Cam Actuator Mounting Plate (2)

Installation Procedure

Fig. 31: Mode Control Cam Actuator Mounting Plate & Bolts Courtesy of GENERAL MOTORS COMPANY

1. Install Mode Control Cam Actuator Mounting Plate (2)

CAUTION: Refer to Fastener Caution .

2. Install Mode Control Cam Actuator Mounting Plate Bolt (1) and tighten 2.5 N.m (22 lb in)

Fig. 32: Mode Control Cam Actuator

Courtesy of GENERAL MOTORS COMPANY

3. Install Mode Control Cam Actuator (2)Mode Control Cam Actuator Replacement

Fig. 33: Temperature Valve Actuator

Courtesy of GENERAL MOTORS COMPANY

4. Install Temperature Valve Actuator (2)Temperature Valve Actuator Replacement

Fig. 34: Floor Front Air Outlet Duct - Left Side Courtesy of GENERAL MOTORS COMPANY

5. Floor Front Air Outlet Duct - Left Side (2)Floor Front Air Outlet Duct Replacement - Left Side

TEMPERATURE VALVE ACTUATOR REPLACEMENT

Fig. 35: Temperature Valve Actuator

Courtesy of GENERAL MOTORS COMPANY

FLOOR AIR TEMPERATURE SENSOR REPLACEMENT

Fig. 36: Floor Air Temperature Sensor Courtesy of GENERAL MOTORS COMPANY

INSIDE AIR TEMPERATURE SENSOR REPLACEMENT - LEFT SIDE UPPER

Fig. 37: Inside Air Temperature Sensor - Left Side Upper Courtesy of GENERAL MOTORS COMPANY

INSIDE AIR MOISTURE AND WINDSHIELD TEMPERATURE SENSOR REPLACEMENT

Fig. 38: Inside Air Moisture And Windshield Temperature Sensor Courtesy of GENERAL MOTORS COMPANY

SUN LOAD TEMPERATURE AND HEADLAMP AUTOMATIC CONTROL AMBIENT LIGHT SENSOR REPLACEMENT

Fig. 39: Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor Courtesy of GENERAL MOTORS COMPANY

DESCRIPTION AND OPERATION

AUTOMATIC HVAC DESCRIPTION AND OPERATION

The air temperature and the air delivery description and operation are divided into the following areas: HVAC Control Components

Air Speed

Air Delivery

Heating and A/C Operation Recirculation Operation

Automatic Operation

Coolant Heater Control Module

Engine Coolant and A/C System Refrigerant

HVAC Control Components

HVAC Control

The HVAC control contains all switches, which are required to control the functions of HVAC and serve as interface between the operator and the HVAC control module. The selected values are passed to the HVAC control module via serial data.

HVAC Control Module

The HVAC control module is a serial data device that interfaces between the operator and the HVAC system to maintain and control desired air temperature and air distribution settings. The battery positive voltage circuit provides power that the HVAC control module uses for keep alive memory. If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from keep alive memory. The body control module (BCM), which is the vehicle power mode master, provides a device ON-Signal. The HVAC control module provides blower, air delivery mode and air temperature settings.

The HVAC control module supports the following features:

Actuators

Doors in the HVAC case assembly are used to control air flow. The HVAC control module operates the doors through the use of actuators, with one actuator being used for each door. The system has the following air control doors and associated actuators: mode, temperature, and recirculation.

Each actuator used in the system is a 5-wire stepper motor. The HVAC control module supplies a 12 V reference voltage to the stepper motor and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motor moves the associated air control door into the calculated position in order to reach the selected position. The null point of the stepper motor will be calibrated, if the stepper motor is new. When the stepper motor is calibrated, the HVAC control module can drive the applicable coil to reach exactly the desired position of the air control door.

Blower Motor

The blower motor speed control signal from the HVAC control module, battery positive and ground circuits enable the blower motor to operate. The blower motor control circuitry is integrated within the blower motor assembly. The HVAC control module provides a ground pulse width modulation (PWM) signal to the blower motor to request a specific motor speed. The blower motor translates the PWM signal and drives the motor accordingly.

Duct Temperature Sensors

The air temperature sensors are 2-wire negative temperature co-efficient thermistors. The sensors operate within a temperature range of -40 to +85°C (-40 to +185°F). The sensors are installed in the air distribution ducts and measure the temperature of the air that streams from the ducts. The HVAC control module uses these values to calculate the mixed air flap position.

A/C Refrigerant High Pressure Sensor

The A/C refrigerant pressure sensor is a 3-wire piezoelectric pressure transducer. A 5 V reference voltage, low reference, and signal circuits enable the sensor to operate. The A/C pressure signal can be between 0.2 - 4.8 V. When the A/C refrigerant pressure is low, the signal value is near 0 V. When the A/C refrigerant pressure is high, the signal value is near 5 V. The engine control module (ECM) converts the voltage signal to a pressure value. When pressure is too high or too low, the ECM will not allow the A/C compressor to engage.

A/C Refrigerant Low Pressure Sensor

The A/C refrigerant pressure sensor is a 3-wire piezoelectric pressure transducer. A 5 V reference voltage, low reference, and signal circuits enable the sensor to operate. The A/C pressure signal can be between 0.2 - 4.8 V. When the A/C refrigerant pressure is low, the signal value is near 0 V. When the A/C refrigerant pressure is high, the signal value is near 5 V. The Hybrid/EV Powertrain Control Module 2 monitors the low side refrigerant pressure through the A/C pressure sensor.

A/C Compressor

The AC compressor function is to provide refrigerant flow in the AC refrigerant loop to help cool down the cabin, help dehumidify the air in a defrost mode and help maintain the battery temperature. Rather than a more- typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes high voltage direct current from the vehicle's high voltage battery and inverts it to alternating current for the motor. The AC compressor shall be activated when any of the three following events occur:

The customer pushes the AC button or

The HVAC control, in ECO climate or Comfort Climate Settings, requests the electric AC compressor on to help in cooling the cabin or removing moisture in conditions where the windows may fog or

The hybrid/EV powertrain control module 2 requests the AC compressor on to help maintain the battery temperature

The hybrid/EV powertrain control module 2 uses values from the A/C refrigerant pressure sensor, duct temperature sensors, ambient air temperature sensor, passenger compartment temperature sensor, battery cell temperature sensors, battery coolant temperature sensors, and battery coolant pumps to determine the speed at which the compressor will operate. This message is sent from the hybrid/EV powertrain control module 2 to the A/C compressor control module via serial data message.

Ambient Light/Sunload Sensor

The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor. This sensor assembly provides information about:

Sun heat intensity

Passenger compartment temperature

The solar sensor is connected to ground and to a 5 V stabilized voltage supply through the HVAC control module. As the sunload increases, the sensor signal voltage also increases and vice versa. The signal varies between 1.4 - 4.5 V and is provided to the HVAC control module.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0 - 5 V.

Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Windshield Temperature and Inside Moisture Sensor

The windshield temperature and inside moisture sensor includes the relative humidity sensor, windshield temperature sensor and humidity sensing element temperature sensor.

This sensor assembly provides information about:

Relative humidity level at windshield (compartment side) Temperature of the windshield inside (compartment side) Temperature of the humidity sensor element

The relative humidity sensor measures the relative humidity of the compartment side of the windshield. It also detects the temperature of the windshield surface on the passenger compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield. The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element.

HVAC Coolant Pump

The coolant heater pump is controlled by a relay. When operating conditions exist that requires coolant flow when the engine is not operating, the HVAC control module turns ON the heater coolant pump by applying ground to the relay control circuit which energizes the heater coolant pump relay.

Air Speed

The blower control switch is part of the HVAC faceplate control. The selected value of the blower switch position is sent to the HVAC control module via serial data.

The blower motor control circuitry is integrated within the blower motor assembly. The HVAC control module provides a ground pulse width modulation (PWM) signal to the blower motor to request a specific motor speed. The blower motor translates the PWM signal and drives the motor accordingly.

Air Delivery

The HVAC control module controls the distribution of air within the passenger compartment by the use of the mode actuator. The modes that may be selected are:

Defrost Defog Panel

Floor

BiLevel

In auto mode, the air delivery mode is controlled automatically based on cooling/warming needs of the compartment. The desired air distribution mode can be selected with the air distribution buttons at the HVAC faceplate control. The HVAC control delivers the values to the HVAC control module via serial data. The HVAC control module controls the mode actuator so that it drives the flap to the calculated position. Depending on the position of the flap, air is distributed through various ducts leading to the outlets in the dash. Turning the mode flap to the defrost position, the HVAC control module will move the recirculation actuator to outside air, reducing window fogging. When defrost is selected, the blower motor will be activated. The HVAC control module enables a high volume of air delivered to the front defrost vents. A/C is available in all modes.

The rear window defogger does not affect the HVAC system.

Recirculation Operation

The recirculation switch is integrated into the HVAC control. The selected recirculation switch position is sent to the HVAC control module via LIN-Bus. The HVAC control module controls the air intake using the recirculation actuator. In recirculation mode the recirculation door opens in order to circulate the air within the vehicle. In fresh air mode the recirculation door is closed in order to route outside air into the vehicle.

Inside air recirculation is prevented if the defrost mode is active. When the defrost mode is active, the recirculation actuator opens the recirculation door and outside air is circulated to the windshield to reduce fogging.

In automatic mode the values of the windshield temperature and inside moisture sensor are used as control inputs for the HVAC control module application to calculate the fog risk on passenger compartment side of the windshield compartment side. The A/C compressor and the defrost mode are activated to prevent or remove fog on the passenger compartment side of the windshield.

Heating and A/C Operation

The purpose of the heating and A/C system is to provide heated and cooled air to the interior of the vehicle. The A/C system will also remove humidity from the interior and reduce windshield fogging. Regardless of the temperature setting, the following can affect the rate that the HVAC system can achieve the desired temperature:

Ambient air temperature

Difference between inside and desired temperature Blower motor speed setting

Mode setting

Air conditioning control module operation

Hybrid/EV powertrain control module 2 operation Coolant heater control module

Pressing the climate mode buttons (MAX Mode or ECO Mode) enables the HVAC control module to determine whether to request A/C compressor and coolant heater activation, based on the thermal conditions of the vehicle and the temperature selected. The HVAC control module sends a serial data message to the hybrid/EV powertrain control module 2 to request A/C compressor operation or sends the heating request to the coolant heater control module to produce heat.

The mode selected modifies the effect of operating the HVAC system with the vehicle's operating range. ECO mode provides a balance between comfort and economy, while MAX mode is biased for best cabin comfort.

If neither ECO or MAX is selcted, the system operates in Fan Only mode. Air conditioning and heating are disabled unless overridden by dehumidification requirements or if MAX DEFROST is selected. This mode has the least effect on the vehicles range.

Automatic Operation

The user can select to operate the Blower, Recirculation and Air Delivery operations in auto per auto operation mode.

When the auto button is pressed, the system responds by putting the blower, air delivery and recirculation into auto mode. If any of these functions are adjusted then the auto button indication shall go off and that function will leave auto operation and follow the user requested setting. In this setting the blower request is adjusted to quickly heat the cabin initially. After comfort is reached, the blower speed is minimized to reduce noise and temperature drifts.

Under cold ambient temperatures, the automatic HVAC system provides heat in the most efficient manner. The operator can select an extreme temperature setting but the system will not warm the vehicle any faster. Under warm ambient temperatures, the automatic HVAC system also provides air conditioning in the most efficient manner. Selecting an extreme cool temperature will not cool the vehicle any faster.

In automatic mode the values of the windshield temperature and inside moisture sensor are used as control inputs for the HVAC control module application to calculate the fog risk on the passenger compartment side of the windshield and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The A/C compressor and the defrost mode may be activated to prevent or remove fog on the passenger compartment side of the windshield. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield.

Coolant Heater Control Module

The coolant heater control module is a high voltage electric heater. High voltage is supplied from the hybrid/EV battery pack. A fused battery input, ground, and LIN serial data from the HVAC control module are used to control the operation of the coolant heater control module.

The coolant heater control module is an essential element of the hybrid heating system. The hybrid/EV powertrain control module 2 controls the passenger compartment heater coolant control valve, and the HVAC commands the coolant heater control module activation via serial data. Heated coolant either from the engine or the coolant heater control module will meet HVAC temperature demands. The coolant heater control module

will be commanded "off" if the coolant temperature exceeds the desired temperature.

Coolant heat generated by the engine is also an element of the heating system. Once the engine coolant is warm enough to supply the required heat, the passenger compartment heater coolant control valve will move to the 'link' position, which allows sharing of coolant between the engine, the coolant heater control module and passenger compartment heater core. The coolant heater control module power level will be reduced and/or cycled on/off as the engine turns on/off during charge-sustaining mode, maintaining cabin comfort. When the engine is utilized for charge sustaining mode the thermostat will control the normal engine operating coolant temperature. The thermostat also creates a restriction for the cooling system that promotes a positive coolant flow and helps prevent cavitation.

Heater coolant enters the heater core through the inlet heater hose, in a pressurized state. The heater core is located inside the HVAC module. The ambient air drawn through the HVAC module, absorbs the heat of the coolant flowing through the heater core. Heated air is distributed to the passenger compartment, through the HVAC module, for passenger comfort. Opening or closing the air temperature flap controls the amount of heat delivered to the passenger compartment. The coolant exits the heater core through the return heater hose and recirculates back to the system as controlled by the coolant passenger compartment heater coolant control valve.

Engine Coolant and A/C System Refrigerant

For information on engine coolant, coolant flow, A/C refrigerant, and the A/C refrigerant cycle, refer to

Heating and Air Conditioning System Description and Operation .

SPECIAL TOOLS AND EQUIPMENT

SPECIAL TOOLS

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