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‌SPECIFICATIONS

FASTENER SPECIFICATIONS

BRAKES

Hydraulic Brakes - Volt

Single Use Non-Threaded Fasteners/Components

Reusable Threaded Fastener Tightening Specifications

APPROXIMATE FLUID CAPACITIES

BRAKE COMPONENT SPECIFICATIONS

BRAKE SYSTEM SPECIFICATIONS

ADHESIVES, FLUIDS, LUBRICANTS, AND SEALERS

SCHEMATIC WIRING DIAGRAMS

HYDRAULIC BRAKE WIRING SCHEMATICS

Hydraulic Brakes

Fig. 1: Hydraulic Brakes

Courtesy of GENERAL MOTORS COMPANY

DIAGNOSTIC INFORMATION AND PROCEDURES

DTC C0075: BRAKE PEDAL POSITION SENSOR PERFORMANCE

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC C0075

Brake Pedal Position Sensor Performance Symptom Byte Information: Symptom Byte List Circuit/System Description

For an overview of the component/system, refer to: Hydraulic Brake System Description and Operation

Conditions for Running the DTC

Ignition - On / Vehicle - In Service Mode

Conditions for Setting the DTC

Brake Pedal Position Sensor = Out Of Range Actions Taken When the DTC Sets Boost/Blending = Not Available

Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

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. Ignition - On / Vehicle - In Service Mode

2. Verify DTC C0075 is not set.

If the DTC is set

Replace the component: K177 Brake Booster Control Module

If the DTC is not set

3. All OK.

Circuit/System Verification

1. Ignition - On / Vehicle - In Service Mode

2. Verify DTC C0075 is not set.

If the DTC is set

1. Perform all necessary programming and setup procedures for the control module:K177 Brake Booster Control Module

2. Verify the DTC does not set.

If the DTC sets - Replace the component:K177 Brake Booster Control Module If the DTC is not set

3. All OK.

If the DTC is not set

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References

DTC C0579, C057A, OR C057E: BRAKE BOOSTER CONTROL MODULE TEMPERATURE SENSOR

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC C0579

Brake Booster Control Module Temperature Sensor 2 Circuit Low Voltage

DTC C057A

Brake Booster Control Module Temperature Sensor 2 Circuit High Voltage

DTC C057E

Brake Booster Control Module Temperature Sensor 1-2 Correlation

Symptom Byte Information: Symptom Byte List

Circuit/System Description

For an overview of the component/system, refer to: Hydraulic Brake System Description and Operation

Conditions for Running the DTC

Ignition - On / Vehicle - In Service Mode

Conditions for Setting the DTC

Brake Booster Temperature = Out Of Range

Actions Taken When the DTC Sets

Boost= Full

Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

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. Ignition - On / Vehicle - In Service Mode

2. Verify DTC C0579, C057A, C057E is not set.

If the DTC is set

1. Perform all necessary programming and setup procedures for the control module:K177 Brake Booster Control Module

2. Verify the DTC does not set.

If the DTC sets - Replace the component:K177 Brake Booster Control Module If the DTC is not set

3. All OK.

If the DTC is not set

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References

DTC C057F, C0582, C058A, C0590, C0591, C0595, C0596, OR C1275-C1277: BRAKE BOOSTER MOTOR

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC C057F

Brake Booster Motor 1 Phase U-V-W Circuit

DTC C0582

Brake Booster Motor 1 Phase U-V-W Circuit Performance

DTC C058A

Brake Booster Motor 1 Position Sensor Circuit Performance

DTC C0590

Brake Booster Motor 1 Phase U-V-W Circuit High Current

DTC C0591

Brake Booster Motor 1 Phase U-V-W Circuit Low Current

DTC C0595

Brake Booster Control Module Internal Driver Performance

DTC C0596

Brake Booster Motor 1 Current Sensor Circuit Performance

DTC C1275

Brake Booster Motor Position Sensor Unexpected Reset

DTC C1276

Brake Booster Motor Position Sensor Message Counter Incorrect

DTC C1277

Brake Booster Motor Position Sensor Configuration Error Symptom Byte Information: Symptom Byte List Circuit/System Description

For an overview of the component/system, refer to: Hydraulic Brake System Description and Operation

Conditions for Running the DTC

C057F, C0582, C0590, C0591

Ignition - On / Vehicle - In Service Mode Brake Pedal = Released

Automatic Braking Event = None - For greater than 5 s

C058A, C0595, C0596, C1275, C1276, C1277

Vehicle = On

Conditions for Setting the DTC

K177 Brake Booster Control Module = Internal Malfunction

Actions Taken When the DTC Sets Boost/Blending = Not Available Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

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. Ignition - On / Vehicle - In Service Mode

2. Verify DTC C057F, C0582, C058A, C0590, C0591, C0595, C0596, C1275, C1276, C1277 is not set.

If the DTC is set

1. Perform all necessary programming and setup procedures for the control module:K177 Brake Booster Control Module

2. Verify the DTC does not set.

If the DTC sets - Replace the component:K177 Brake Booster Control Module If the DTC is not set

3. All OK.

If the DTC is not set

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References DTC C0580 OR C0594: BRAKE BOOSTER MOTOR

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC C0580

Brake Pedal Position Sensor Performance

DTC C0594

Brake Pedal Position Sensor Performance Symptom Byte Information: Symptom Byte List Circuit/System Description

For an overview of the component/system, refer to: Hydraulic Brake System Description and Operation

Conditions for Running the DTC

Ignition - On / Vehicle - In Service Mode

Conditions for Setting the DTC

Brake Pedal Position Sensor = Out Of Range Actions Taken When the DTC Sets Boost/Blending = Not Available

Brake System Warning Indicator = On

Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

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. Ignition - On / Vehicle - In Service Mode

2. Verify DTC C0580, C0594 is not set.

If the DTC is set

1. Perform all necessary programming and setup procedures for the control module:K177 Brake Booster Control Module

2. Verify the DTC does not set.

If the DTC sets - Replace the component:K177 Brake Booster Control Module If the DTC is not set

3. All OK.

If the DTC is not set

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References DTC C1072: BRAKE FLUID LEVEL SENSOR CIRCUIT

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC C1072

Brake Fluid Level Sensor Circuit

Symptom Byte Information: Symptom Byte List

Diagnostic Fault Information

Circuit/System Description

For an overview of the component/system, refer to:Hydraulic Brake System Description and Operation

Conditions for Running the DTC

Ignition - On / Vehicle - In Service Mode

Conditions for Setting the DTC

Ground circuit = open

Signal circuit = open/Short to Ground

Actions Taken When the DTC Sets Brake System Warning Indicator = On Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References

Circuit/System Verification

1. Ignition/Vehicle - Off

2. Verify the condition does not exist: Incorrect fluid level or condition - Refer to: Master Cylinder Reservoir Filling

If a condition exists

Repair or replace as necessary.

If no condition exists

3. Refer to Circuit/System Testing.

Circuit/System Testing

NOTE: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

1. Ignition/Vehicle & All vehicle systems - Off

2. Disconnect the electrical connector: B20 Brake Fluid Level Switch

3. Test for less than 10 ohms between the test points:Ground circuit terminal 2 & Ground

If 10 ohms or greater

1. Disconnect ground terminal.

2. Test for less than 2 ohms between the test points:Ground circuit terminal 2 @Component harness & The other end of the circuit @ Ground terminal

If 2 ohms or greater - Repair the open/high resistance in the circuit.

If less than 2 ohms - Repair the open/high resistance in the ground connection.

If less than 10 ohms

4. Ignition - On / Vehicle - In Service Mode

5. Verify the scan tool parameter: Brake Fluid Level Sensor = OK

If not the specified state

1. Ignition/Vehicle - Off

2. Disconnect the electrical connector: K17 Electronic Brake Control Module

3. Test for infinite resistance between the test points: Signal circuit terminal 1 @ Component harness & Ground

If less than infinite resistance - Repair the short to ground on the circuit.

If infinite resistance - Replace the component: K17 Electronic Brake Control Module

If the specified state

6. Connect a 3 A fused jumper wire between the test points:Signal circuit terminal 1 & Ground

7. Verify the scan tool parameter: Brake Fluid Level Sensor= Low

If not the specified state

1. Ignition/Vehicle - Off & Remove - Jumper wire(s)

2. Disconnect the electrical connector: K17 Electronic Brake Control Module

3. Ignition - On / Vehicle - In Service Mode

4. Test for less than 1 V between the test points:Signal circuit terminal 1 @Component harness & Ground

If 1 V or greater - Repair the short to voltage on the circuit. If less than 1 V

5. Ignition/Vehicle - Off

6. Test for less than 2 ohms between the test points:Signal circuit terminal 1 @ Component harness & The other end of the circuit @Control module harness

If 2 ohms or greater - Repair the open/high resistance in the circuit.

If less than 2 ohms - Replace the component: K17 Electronic Brake Control Module

If the specified state

8. Test or replace the component: B20 Brake Fluid Level Switch

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References

DTC C111C: LOW BRAKE FLUID INDICATED

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC C111C

Low Brake Fluid Indicated

Symptom Byte Information: Symptom Byte List

Diagnostic Fault Information

Circuit/System Description

For an overview of the component/system, refer to:Hydraulic Brake System Description and Operation

Conditions for Running the DTC

Ignition - On / Vehicle - In Service Mode

Conditions for Setting the DTC

Ground circuit = open

Signal circuit = open/Short to Ground

Actions Taken When the DTC Sets Brake System Warning Indicator = On Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References

Circuit/System Verification

1. Ignition/Vehicle - Off

2. Verify the condition does not exist: Incorrect fluid level or condition - Refer to: Master Cylinder Reservoir Filling

If a condition exists

Repair or replace as necessary.

If no condition exists

3. Refer to Circuit/System Testing.

Circuit/System Testing

NOTE: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

1. Ignition/Vehicle & All vehicle systems - Off

2. Disconnect the electrical connector: B20 Brake Fluid Level Switch

3. Test for less than 10 ohms between the test points:Ground circuit terminal 2 & Ground

If 10 ohms or greater

1. Disconnect ground terminal.

2. Test for less than 1 ohms between the test points:Ground circuit terminal 2 @Component harness & The other end of the circuit @ Ground terminal

If 2 ohms or greater - Repair the open/high resistance in the circuit.

If less than 2 ohms - Repair the open/high resistance in the ground connection.

If less than 10 ohms

4. Ignition - On / Vehicle - In Service Mode

5. Verify the scan tool parameter: Brake Fluid Level Sensor = OK

If not the specified state

1. Ignition/Vehicle - Off

2. Disconnect the electrical connector: K17 Electronic Brake Control Module

3. Test for infinite resistance between the test points: Signal circuit terminal 1 @ Component harness & Ground

If less than infinite resistance - Repair the short to ground on the circuit.

If infinite resistance - Replace the component: K17 Electronic Brake Control Module

If the specified state

6. Connect a 3 A fused jumper wire between the test points:Signal circuit terminal 1 & Ground

7. Verify the scan tool parameter: Brake Fluid Level Sensor= Low

If not the specified state

1. Ignition/Vehicle - Off & Remove - Jumper wire(s)

2. Disconnect the electrical connector: K17 Electronic Brake Control Module

3. Ignition - On / Vehicle - In Service Mode

4. Test for less than 1 V between the test points:Signal circuit terminal 1 @Component harness & Ground

If 1 V or greater - Repair the short to voltage on the circuit. If less than 1 V

5. Ignition/Vehicle - Off

6. Test for less than 2 ohms between the test points:Signal circuit terminal 1 @ Component harness & The other end of the circuit @Control module harness

If 2 ohms or greater - Repair the open/high resistance in the circuit.

If less than 2 ohms - Replace the component: K17 Electronic Brake Control Module

If the specified state

8. Test or replace the component: B20 Brake Fluid Level Switch

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References DTC C1278 OR C1279: BRAKE SYSTEM DATA 2 MESSAGE COUNTER INCORRECT

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC C1278

Brake System Data 1 Message Counter Incorrect

DTC C1279

Brake System Data 2 Message Counter Incorrect Symptom Byte Information: Symptom Byte List Circuit/System Description

For an overview of the component/system, refer to: Hydraulic Brake System Description and Operation

Conditions for Running the DTC

Ignition - On / Vehicle - In Service Mode

Conditions for Setting the DTC

K177 Brake Booster Control Module = Internal Malfunction

Actions Taken When the DTC Sets

Boost = Full

Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

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. Ignition - On / Vehicle - In Service Mode

2. Verify DTC C1278, C1279 is not set.

If the DTC is set

1. Perform all necessary programming and setup procedures for the control module:K177 Brake Booster Control Module

2. Verify the DTC does not set.

If the DTC sets - Replace the component:K177 Brake Booster Control Module If the DTC is not set

3. All OK.

If the DTC is not set

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References DTC C1449: SYSTEM CONFIGURATION ERROR

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC C1449

System Configuration Error

Symptom Byte Information: Symptom Byte List

Circuit/System Description

For an overview of the component/system, refer to: Hydraulic Brake System Description and Operation

Conditions for Running the DTC

Ignition - On / Vehicle - In Service Mode

Conditions for Setting the DTC

K177 Brake Booster Control Module = Internal Malfunction

Actions Taken When the DTC Sets

Boost/Blending = Not Available

Brake System Warning Indicator = ON

Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

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. Ignition - On / Vehicle - In Service Mode

2. Verify DTC C1449 is not set.

If the DTC is set

1. Perform all necessary programming and setup procedures for the control module:K177 Brake Booster Control Module

2. Verify the DTC does not set.

If the DTC sets - Replace the component:K177 Brake Booster Control Module If the DTC is not set

3. All OK.

If the DTC is not set

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References DTC P057B-P057E, P05DC-P05DF, OR P05E0: BRAKE PEDAL POSITION 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 Descriptor

DTC P057B

Brake Pedal Position Sensor 1 Performance

DTC P057C

Brake Pedal Position Sensor Circuit Low Voltage

DTC P057D

Brake Pedal Position Sensor 1 Circuit High Voltage

DTC P057E

Brake Pedal Position Sensor Circuit Erratic

DTC P05DC

Brake Pedal Position Sensor "B" Circuit Range/Performance

DTC P05DD

Brake Pedal Position Sensor 2 Circuit Low Voltage

DTC P05DE

Brake Pedal Position Sensor 2 Circuit High Voltage

DTC P05DF

Brake Pedal Position Sensor 2 Circuit Erratic

DTC P05E0

Brake Pedal Position Sensors 1-2 Not Plausible

For symptom byte information refer to Symptom Byte List .

Diagnostic Fault Information

Circuit/System Description

The brake booster system consists of a motor, electronic control unit (ECU), pedal travel sensor, and a master cylinder. The pedal travel sensor is connected to the brake pedal and measures the amount of brake pedal input to control the amount of boost needed. The pedal travel sensor consists of two travel sensors in one assembly, consisting of a shared 5 volt reference, shared low reference, and two signal circuits.

Conditions for Running the DTC

P057B, P057C, P057D, P057E, P05DC, P05DD, P05DE, P05DF, or P05E0

Ignition ON/Vehicle in Service Mode.

Conditions for Setting the DTC

P057B

The brake pedal position sensor 1 upper and lower and lower range has been exceeded

P057E

Brake pedal position sensor 1 erratic signal

P057C

Brake pedal position sensor 1 signal shorted to ground

P057D

Brake pedal position sensor 1 signal shorted to voltage

P05DC

The brake pedal position sensor 2 upper and lower and lower range has been exceeded

P05DD

Brake pedal position sensor 2 signal shorted to ground

P05DE

Brake pedal position sensor 2 signal shorted to voltage

P05DF

Brake pedal position sensor 2 erratic signal

P05E0

The deviation between Brake pedal position sensor 1 and 2 is too large

Action Taken When the DTC Sets

P057B, P057C, P057D, P057E, P05DC, P05DD, P05DE, P05DF, or P05E0

No boost or blending is available

Red brake light and MIL are illuminated

Conditions for Clearing the DTC

P057B, P057C, P057D, P057E, P05DC, P05DD, P05DE, P05DF, or P05E0

The condition for setting the DTC is no longer present.

Diagnostic Aids

DTC P050E may set if the brake pedal is applied for 60 seconds or more while also applying the accelerator pedal.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Hydraulic Brake System 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. Ignition OFF/Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B201 Brake Control Brake Pedal Position Sensor. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the low reference circuit terminal 3 and ground.

If 10 Ω or greater

1. Disconnect the harness connector at the K177 Brake Booster 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 K177 Brake Booster Control Module.

If less than 10 Ω

3. Ignition ON/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. Ignition OFF/Ignition OFF/Vehicle OFF, disconnect the harness connector at the K177 Brake Booster 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 K177 Brake Booster Control Module.

If greater than 5.2 V

1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K177 Brake Booster Control Module, Ignition ON/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 K177 Brake Booster Control Module.

If between 4.8 - 5.2 V

5. Test for less than 1 V between the B201 Brake Control Brake Pedal Position Sensor signal circuit terminal 2 and ground.

If greater than 1 V

1. Ignition OFF/Ignition OFF/Vehicle OFF, disconnect the harness connector at the K177 Brake Booster Control Module, ignition ON.

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 K177 Brake Booster Control Module.

If less than 1 V

6. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K177 Brake Booster Control Module.

7. Test for infinite resistance between the B201 Brake Control Brake Pedal Position Sensor signal circuit terminal 2 and ground.

If less than infinite resistance

Repair the short to ground on the circuit.

If infinite resistance

8. Test for less than 2 Ω in the B201 Brake Control Brake Pedal Position Sensor signal circuit end to end.

If 2 Ω or greater

Repair the open/high resistance in the circuit.

If less than 2 Ω

9. Test for less than 1 V between the B201 Brake Control Brake Pedal Position Sensor signal circuit terminal 4 and ground.

If greater than 1 V

1. Ignition OFF/Ignition OFF/Vehicle OFF, disconnect the harness connector at the K177 Brake Booster Control Module, ignition ON.

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 K177 Brake Booster Control Module.

If less than 1 V

10. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K177 Brake Booster Control Module.

11. Test for infinite resistance between the B201 Brake Control Brake Pedal Position Sensor signal circuit terminal 4 and ground.

If less than infinite resistance

Repair the short to ground on the circuit.

If infinite resistance

12. Test for less than 2 Ω in the B201 Brake Control Brake Pedal Position Sensor signal circuit end to end.

If 2 Ω or greater

Repair the open/high resistance in the circuit.

If less than 2 Ω

13. Replace the K177 Brake Booster Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for control module replacement, programming and setup

DTC P0601, P0603, P0604, P0606, P060B, OR P062F: CONTROL MODULE

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC P0601

Control Module Read Only Memory Performance

DTC P0603

Control Module Long Term Memory Reset

DTC P0604

Control Module Random Access Memory Performance

DTC P0606

Control Module Processor Performance

DTC P060B

Control Module Analog to Digital Converter Performance

DTC P062F

Control Module Long Term Memory Performance

Circuit/System Description

For an overview of the component/system, refer to: Hydraulic Brake System Description and Operation

Conditions for Running the DTC

Ignition - On / Vehicle - In Service Mode

Conditions for Setting the DTC

K177 Brake Booster Control Module = Internal Malfunction

Actions Taken When the DTC Sets

Brake System Warning Indicator = ON

Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

A history DTC will clear after 50 consecutive malfunction-free ignition cycles.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

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. Ignition - On / Vehicle - In Service Mode

2. Verify DTC P0601, P0603, P0604, P0606, P060B, P062F is not set.

If the DTC is set

1. Perform all necessary programming and setup procedures for the control module:K177 Brake Booster Control Module

2. Verify the DTC does not set.

If the DTC sets - Replace the component:K177 Brake Booster Control Module If the DTC is not set

3. All OK.

If the DTC is not set

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References DTC P0642, P06A6, OR P06A7: SENSOR REFERENCE 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 Descriptor

DTC P0642

Sensor Reference Voltage 1 Low Voltage

DTC P06A6

Sensor Reference Voltage 1 Performance

DTC P06A7

Sensor Reference Voltage 2 Performance

For symptom byte information refer to Symptom Byte List .

Diagnostic Fault Information

Circuit/System Description

The brake booster system consists of a motor, electronic control unit (ECU), pedal travel sensor, and a master cylinder. The pedal travel sensor is attached to the brake pedal and measures the amount of brake pedal input to control the amount of boost needed. The pedal travel sensor consists of two travel sensors in one assembly, consisting of a shared 5 volt reference, shared low reference, and two signal circuits.

Conditions for Running the DTC Ignition ON/Vehicle in Service Mode. Conditions for Setting the DTC

Pedal travel sensor voltage supply failure

Action Taken When the DTC Sets

No boost or blending available

Red brake light and MIL are illuminated

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Hydraulic Brake System 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. Ignition OFF/Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B201 Brake Control Brake Pedal Position Sensor. It may take up to 2 min for all vehicle systems to power down.

2. Ignition ON/Vehicle in Service Mode.

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

If less than 4.8 V

1. Ignition OFF/Ignition OFF/Vehicle OFF, disconnect the harness connector at the K177 Brake Booster 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 K177 Brake Booster Control Module.

If greater than 5.2 V

1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K177 Brake Booster Control Module, Ignition ON/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 K177 Brake Booster Control Module.

If between 4.8 - 5.2 V

4. Replace the K177 Brake Booster Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for control module replacement, programming and setup

DTC P25C6 OR P25C7: BRAKE BOOSTER TEMPERATURE SENSOR

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC P25C6

Brake Booster Temperature Sensor Circuit Low Voltage

DTC P25C7

Brake Booster Temperature Sensor 1 Circuit High Voltage Symptom Byte Information: Symptom Byte List Circuit/System Description

For an overview of the component/system, refer to: Hydraulic Brake System Description and Operation

Conditions for Running the DTC

Ignition - On / Vehicle - In Service Mode

Conditions for Setting the DTC

Brake Booster Control Module Temperature= Out Of Range

Actions Taken When the DTC Sets

Boost = Full

Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

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. Ignition - On / Vehicle - In Service Mode

2. Verify DTC P25C6, P25C7 is not set.

If the DTC is set

1. Perform all necessary programming and setup procedures for the control module:K177 Brake Booster Control Module

2. Verify the DTC does not set.

If the DTC sets - Replace the component:K177 Brake Booster Control Module If the DTC is not set

3. All OK.

If the DTC is not set

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References SYMPTOMS - HYDRAULIC BRAKES

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

1. Perform Diagnostic System Check - Vehicle before using the brake indicator symptom tables in order to verify that all of the following are true:

There are no DTCs set.

The control module(s) can communicate via the serial data link.

2. Perform the Brake System Vehicle Road Test before using the hydraulic brake symptom tables in order to duplicate the customer's concern.

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

Power Brake Booster Description and Operation

Brake Warning System Description and Operation Hydraulic Brake System Description and Operation Disc Brake System Description and Operation

Visual/Physical Inspection

Inspect for aftermarket devices which could affect the operation of the brake warning system. Checking Aftermarket Accessories

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

Intermittent

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

Symptom List

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

Brake Warning Indicator Malfunction Brake Pulsation

Brake System Noise

Braking Action Uneven - Pulls to One Side Braking Action Uneven - Front to Rear

Brake Pedal Excessive Travel Brake Pedal Excessive Effort Brakes Drag

Brake System Slow Release Brake Fluid Loss

BRAKE WARNING INDICATOR MALFUNCTION

Diagnostic Instructions

Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle

Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis

An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC C1072

Brake Fluid Level Sensor Circuit

Symptom Byte Information: Symptom Byte List

Diagnostic Fault Information

Circuit/System Description

For an overview of the component/system, refer to:Hydraulic Brake System Description and Operation

Conditions for Running the DTC

Ignition - On / Vehicle - In Service Mode

Conditions for Setting the DTC

Ground circuit = open

Signal circuit = open/Short to Ground

Actions Taken When the DTC Sets Brake System Warning Indicator = On Conditions for Clearing the DTC

The conditions for setting the DTC no longer exist.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References

Circuit/System Verification

1. Ignition/Vehicle - Off

2. Verify the condition does not exist: Incorrect fluid level or condition - Refer to: Master Cylinder Reservoir Filling

If a condition exists

Repair or replace as necessary.

If no condition exists

3. Refer to Circuit/System Testing.

Circuit/System Testing

NOTE: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

1. Ignition/Vehicle & All vehicle systems - Off

2. Disconnect the electrical connector: B20 Brake Fluid Level Switch

3. Test for less than 10 ohms between the test points:Ground circuit terminal 2 & Ground

If 10 ohms or greater

1. Disconnect ground terminal.

2. Test for less than 2 ohms between the test points:Ground circuit terminal 2 @Component harness & The other end of the circuit @ Ground terminal

If 2 ohms or greater - Repair the open/high resistance in the circuit.

If less than 2 ohms - Repair the open/high resistance in the ground connection.

If less than 10 ohms

4. Ignition - On / Vehicle - In Service Mode

5. Verify the scan tool parameter: Brake Fluid Level Sensor = OK

If not the specified state

1. Ignition/Vehicle - Off

2. Disconnect the electrical connector: K17 Electronic Brake Control Module

3. Test for infinite resistance between the test points: Signal circuit terminal 1 @ Component harness & Ground

If less than infinite resistance - Repair the short to ground on the circuit.

If infinite resistance - Replace the component: K17 Electronic Brake Control Module

If the specified state

6. Connect a 3 A fused jumper wire between the test points:Signal circuit terminal 1 & Ground

7. Verify the scan tool parameter: Brake Fluid Level Sensor= Low

If not the specified state

1. Ignition/Vehicle - Off & Remove - Jumper wire(s)

2. Disconnect the electrical connector: K17 Electronic Brake Control Module

3. Ignition - On / Vehicle - In Service Mode

4. Test for less than 1 V between the test points:Signal circuit terminal 1 @Component harness & Ground

If 1 V or greater - Repair the short to voltage on the circuit. If less than 1 V

5. Ignition/Vehicle - Off

6. Test for less than 2 ohms between the test points:Signal circuit terminal 1 @ Component harness & The other end of the circuit @Control module harness

If 2 ohms or greater - Repair the open/high resistance in the circuit.

If less than 2 ohms - Replace the component: K17 Electronic Brake Control Module

If the specified state

8. Test or replace the component: B20 Brake Fluid Level Switch

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

For control module replacement, programming, and setup refer to: Control Module References

BRAKE PULSATION

BRAKE SYSTEM NOISE

BRAKING ACTION UNEVEN - PULLS TO ONE SIDE

Test Description

The numbers below refer to the step numbers on the diagnostic table.

4

Suspension components that are not operating properly may cause a disturbance to the vehicle during application of the brake system.

5

Steering components that are not operating properly may cause a disturbance to the vehicle during application of the brake system.

BRAKING ACTION UNEVEN - FRONT TO REAR

Test Descriptions

The number below refers to the step number on the diagnostic table.

4

Suspension components that are not operating properly may cause a disturbance to the vehicle during application of the brake system.

BRAKE PEDAL EXCESSIVE TRAVEL

BRAKE PEDAL EXCESSIVE EFFORT

BRAKES DRAG

BRAKE SYSTEM SLOW RELEASE

BRAKE FLUID LOSS

DISC BRAKE SYSTEM DIAGNOSIS

Test Description

The numbers below refer to the step numbers on the diagnostic table:

9

Lubricant leaks from non-brake system components may come in contact with and contaminate brake system components.

10

Lubricant leaks from non-brake system components may come in contact with and contaminate brake system components.

12

Disc brake rotor shields/backing plates that come in contact with disc brake rotors may cause brake system noise.

15

Disc brake rotor thickness variation that exceeds the maximum acceptable level can cause brake pulsation.

19

Disc brake rotor thickness variation that exceeds the maximum acceptable level can cause brake pulsation.

22

Disc brake rotor assembled lateral runout (LRO) that exceeds the maximum acceptable level can lead to thickness variation.

HYDRAULIC BRAKE SYSTEM DIAGNOSIS

BRAKE SYSTEM VEHICLE ROAD TEST

Preliminary Inspections

1. Visually inspect easily accessible brake system components for obvious damage and/or leaks which may indicate that the vehicle should not be driven until further inspections have been completed.

2. Inspect the brake master cylinder reservoir fluid level and adjust only if necessary for brake system road testing. Master Cylinder Reservoir Filling

3. Inspect the tire inflation pressures and adjust as necessary.

4. Inspect the tire tread patterns to ensure that they are the same or very similar, especially per axle.

5. Ensure that the vehicle is not loaded unevenly prior to brake system road testing.

Road Testing Procedure

WARNING: Road test a vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.

1. Start the engine and allow it to idle.

2. Check to see if the brake system warning lamp remains illuminated.

3. If the brake system warning lamp remains illuminated, DO NOT proceed to test drive the vehicle until it is diagnosed and repaired. Symptoms - Hydraulic Brakes

4. Select a smooth, dry, clean and level road or large lot that is as free of traffic and obstacles as possible for brake system low speed road testing.

5. With the transmission in PARK, lightly apply the brake pedal. Observe both the pedal feel and the pedal travel.

6. If the brake pedal apply felt spongy, or the pedal travel was excessive, DO NOT drive the vehicle until it is repaired.

7. If the brake pedal apply did not feel spongy and the pedal travel was not excessive, proceed to step 8.

8. Release and apply the brakes.

9. While continuing to apply the brakes, shift the transmission into DRIVE, release the brakes and allow the engine to idle the vehicle away from the stopped position. Observe for a slow release of the brake system.

10. With the aid of an assistant to observe the vehicle's performance from outside of the vehicle, drive the vehicle at a low speed and lightly apply the brakes while driving past the assistant. Have the assistant observe for brake system noise from the side of the vehicle closest to them, while you observe both the pedal effort and the pedal travel.

11. If the brake pedal apply effort was excessive, or the pedal travel was excessive, DO NOT continue to test drive the vehicle until it is repaired.

12. If the brake pedal apply effort was not excessive and the pedal travel was not excessive, proceed to step 13.

13. Drive the vehicle in the opposite direction, at the same low speed and lightly apply the brakes while driving past the assistant. Have the assistant observe for brake system noise from the side of the vehicle closest to him.

14. Drive the vehicle at a low speed and shift the transmission into NEUTRAL without applying the brakes. Observe for a rapid deceleration in vehicle speed, indicating possible brake drag.

15. Select a smooth, dry, clean and level road that is as free of heavy traffic as possible for brake system moderate speed road testing.

16. Drive the vehicle at a moderate speed. Observe for a pull and/or incorrect tracking of the vehicle without the brakes applied.

17. While continuing to drive the vehicle at a moderate speed, perform several light applies of the brakes. Observe the pedal effort and the pedal travel, observe for brake system noise, pulsation and/or brake drag.

18. If the brake pedal apply effort was excessive, or the pedal travel was excessive, DO NOT continue to test drive the vehicle until it is repaired.

19. If the brake pedal apply effort was not excessive and the pedal travel was not excessive, proceed to step 20.

20. While continuing to drive the vehicle at a moderate speed, perform several moderate applies of the brakes. Observe the pedal effort and the pedal travel, observe for brake system pulsation and/or uneven braking action - either side to side, or front to rear.

A small amount of vehicle front end dip is expected during a moderate apply of the brakes.

21. If the brake pedal apply effort was excessive, or the pedal travel was excessive, DO NOT continue to test

drive the vehicle until it is repaired.

BRAKE PEDAL TRAVEL MEASUREMENT AND INSPECTION

Special Tools

CH-28662 Brake Pedal Effort Gauge

For equivalent regional tools, refer to Special Tools.

1. Perform this procedure with the power OFF and the brakes cool.

Fig. 2: Steering Wheel, Brake Pedal And Gauge Courtesy of GENERAL MOTORS COMPANY

2. Install the CH-28662 gauge (1), or equivalent, to the brake pedal (3).

3. Measure and record the distance (a) from the brake pedal (3) to the rim of the steering wheel (2). Note the points of measurement.

Fig. 3: Brake Pedal Components And Travel Measurement Courtesy of GENERAL MOTORS COMPANY

4. Apply and maintain a force of 445 N (100 lb) to the brake pedal, as indicated on the CH-28662 gauge (1), or equivalent.

5. While maintaining 445 N (100 lb) of force to the brake pedal (3), measure and record the distance (b) from the same point on the brake pedal (3) to the same point on the rim of the steering wheel (2).

6. Release the brake pedal (3) and repeat steps 4 and 5 to obtain a second measurement. After obtaining a second measurement, proceed to step 7.

7. Average the first and second measurements recorded for the 2 applies of the brakes.

8. Subtract the initial unapplied distance (a), from the average applied distance (b) to obtain the brake pedal travel measurement (c).

9. Compare the measurement obtained with the specification. Refer to Brake System Specifications.

BRAKE SYSTEM EXTERNAL LEAK INSPECTION

WARNING: Refer to Brake Fluid Irritant Warning .

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

1. In order to inspect for external brake fluid leaks, first check the fluid level in the master cylinder.

While a slight brake fluid level drop can be considered a normal condition due to brake lining wear, a very low level may indicate a brake fluid leak in the hydraulic system.

If the fluid level is abnormally low, adjust the brake fluid level. Master Cylinder Reservoir Filling

2. Start the engine and allow it to idle.

3. Apply constant, moderate foot pressure to the brake pedal.

If the brake pedal gradually falls away while under foot pressure, there may be a brake fluid leak.

4. Turn OFF the ignition.

5. Visually inspect the following brake system components for brake fluid leaks, excessive corrosion, and damage. Give particular attention to all brake pipe and flexible hose connections to ensure that there are not any slight brake fluid leaks - even though the brake pedal may feel firm and hold steady:

Master cylinder brake pipe fittings All brake pipe connections

Brake pipes

Brake hoses and connections

Brake calipers and/or wheel cylinders, if equipped

6. While slight dampness around the master cylinder reservoir can be considered acceptable, brake fluid leaking from any of the brake system components requires immediate attention. If any of these components exhibit signs of brake fluid leakage, repair or replace those components. After the repair or replacement, reinspect the hydraulic brake system to assure proper function.

BRAKE SYSTEM INTERNAL LEAK TEST

WARNING: Refer to Brake Fluid Irritant Warning .

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

1. Ensure is ignition is OFF for at least 60 seconds to allow the system to depressurize and deplete the power reserve.

2. Apply the brake pedal several times to verify the power reserve is fully depleted.

3. Apply light, steady pressure to the brake pedal. Observe both the brake pedal feel and travel.

4. Release the brake pedal.

5. If the brake pedal apply felt spongy, but the brake pedal travel was not excessive, perform the following steps:

1. Inspect the brake system for external leaks. Brake System External Leak Inspection

2. Pressure bleed the brake system in order to purge any air that may be trapped in the system.

Hydraulic Brake System Bleeding

Fig. 4: Identifying Brake Master Cylinder (Cross Sectional View) Courtesy of GENERAL MOTORS COMPANY

6. If the brake pedal apply did not feel spongy, but the brake pedal travel was excessive, perform the following steps:

1. Loosen the master cylinder-to-adapter mounting nuts.

2. Carefully pull the master cylinder away from the adapter just enough to inspect the mounting surface of the master cylinder.

3. Inspect the master cylinder mounting surface at the primary piston (2) for brake fluid leaks.

7. If the master cylinder exhibits any leakage around the primary piston (2), then the primary piston primary seal (4) and/or secondary seal (3) is leaking and the master cylinder requires replacement.

8. If the master cylinder primary piston (2) does not exhibit any leakage, install the master cylinder to the adapter and pressure bleed the brake system. Hydraulic Brake System Bleeding

9. If the brake pedal apply did not feel spongy, and the brake pedal travel was initially steady and not excessive, but then gradually fell, then the master cylinder requires replacement due to an internal leak past a piston seal.

10. If the brake pedal apply did not feel spongy, and the brake pedal travel was initially steady and not excessive, then fell slightly, then became steady again, then the brake pressure modulator valve (BPMV)

may be leaking internally, and may require replacement.

HYDRAULIC BRAKE COMPONENT OPERATION VISUAL INSPECTION

Fig. 5: Identifying Brake Caliper/Pad Inspection Areas Courtesy of GENERAL MOTORS COMPANY

WARNING: Refer to Brake Fluid Irritant Warning .

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

1. With the tire and wheel assemblies removed and the brake rotors retained by wheel lug nuts, visually inspect the caliper piston dust boot (2) sealing area to ensure that there are no brake fluid leaks.

2. If any evidence of a brake fluid leak is present, the brake caliper requires overhaul or replacement.

3. While the brake system is at rest (4), observe the position of the caliper piston (1) in relation to the caliper housing.

4. Have an assistant apply and release the brake pedal several times while you observe the operation of the hydraulic brake caliper.

1. Observe the caliper piston (1) for unrestricted and even movement during each apply of the brake system (5).

2. Observe the caliper piston (1) for an unrestricted and even return motion during each release of the brake system (6).

5. If the caliper piston (1) did not exhibit unrestricted and even movement during brake system apply and/or release, the piston square seal (3) may be worn or damaged and the caliper may require overhaul or replacement.

BRAKE PIPE AND HOSE INSPECTION

WARNING: Refer to Brake Fluid Irritant Warning .

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

1. Visually inspect all of the brake pipes for the following conditions:

Kinks, improper routing, missing or damaged retainers, Leaking fittings, excessive corrosion

2. If any of the brake pipes exhibited any of the conditions listed, then the identified pipe, or pipes, require replacement.

3. Ensure that the vehicle axles are properly supported at ride height in order to maintain the proper relationship of the flexible brake hoses to the chassis.

Fig. 6: Identifying Flexible Brake Hose Failure Conditions Courtesy of GENERAL MOTORS COMPANY

4. Visually inspect all of the flexible brake hoses for the following conditions:

Kinks (1), improper routing, twists, chafing, missing or damaged retainers Leaking connections, cracking, dry-rot, blisters, bulges

5. If any of the flexible brake hoses exhibited any of the conditions listed, then the identified flexible brake hose, or hoses require replacement.

6. Tightly press the flexible brake hose with fingers to check whether there are any spongy spots (2) (which indicates the existence of interior blocking). Inspect the entire length of each hose.

7. If any of the flexible brake hoses were found to have soft spots (2), then the identified flexible brake hose, or hoses require replacement.

BRAKE PEDAL PUSHROD INSPECTION

Fig. 7: View of Brake Pedal Pushrod

Courtesy of GENERAL MOTORS COMPANY

1. Disconnect the brake pedal pushrod (1) from the brake pedal.

2. Inspect the brake pedal pushrod eyelet bushing (2), if equipped, for cracks and/or excessive wear.

3. Reposition the pedal pushrod boot (3) toward the front of the vehicle to expose as much of the pedal pushrod (1) as possible.

4. Inspect the brake pedal pushrod (1) for straightness.

5. If the brake pedal pushrod eyelet bushing (2) exhibited cracks and/or excessive wear, then the bushing requires replacement.

6. If the brake pedal pushrod (1) is not straight, then the pushrod requires replacement.

7. Return the pedal pushrod boot (3) to its original position on the pedal pushrod (1).

8. Connect the brake pedal pushrod (1) to the brake pedal.

REPAIR INSTRUCTIONS

HYDRAULIC BRAKE FLUID REPLACEMENT

WARNING: Brake Fluid Irritant Warning

CAUTION: Brake Fluid Effects on Paint and Electrical Components Caution

CAUTION: Only use products that comply with GM specifications and check manufacturer information respectively. We recommend the use of GM genuine products.

Instructions must be followed at all times. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.

1. With the engine OFF, apply and release the brake pedal several times until the pedal effort becomes firm to deplete the brake booster power reserve.

2. Clean the outer surface of the master cylinder brake fluid reservoir, on and around the reservoir cap, prior to removing the cap and diaphragm. Master Cylinder Reservoir Filling

3. Fill the master cylinder brake fluid reservoir to the maximum-fill level with GM approved brake fluid from a clean, sealed brake fluid container. Adhesives, Fluids, Lubricants, and Sealers

4. Maintain the brake fluid level in the master cylinder brake fluid reservoir to between the minimum and maximum-fill level during the brake fluid replacement procedure.

5. Following the hydraulic brake system bleeding procedure, bleed each of the hydraulic brake wheel circuits until clean, clear brake fluid is observed coming from each bleeder valve. Hydraulic Brake System Bleeding

6. Fill the master cylinder brake fluid reservoir to the maximum-fill level with GM approved brake fluid from a clean, sealed brake fluid container. Master Cylinder Reservoir Filling

7. Securely install the master cylinder brake fluid reservoir diaphragm and cap.

8. Slowly apply and release the brake pedal, observing the brake pedal feel.

9. If the brake pedal feels spongy, perform the following:

1. Visually inspect the hydraulic brake system for external leaks. Brake System External Leak Inspection

2. Using a scan tool, perform the antilock brake system automated bleed procedure to remove any air that may have become trapped in the brake pressure modulator valve (BPMV). Antilock Brake System Automated Bleed

MASTER CYLINDER RESERVOIR FILLING

WARNING: Refer to Brake Fluid Irritant Warning .

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

Fig. 8: Inspecting Brake Fluid Level Through Brake Master Cylinder Reservoir Courtesy of GENERAL MOTORS COMPANY

1. Visually inspect the brake fluid level through the brake master cylinder reservoir.

2. If the brake fluid level is half way or less between the MAX and MIN levels (1) in the master cylinder reservoir, the brake system should be inspected for wear and possible brake fluid leaks.

3. If the brake fluid level is half way or less between the MAX and MIN levels during routine fluid checks, and an inspection of the brake system did not reveal wear or brake fluid leaks, the brake fluid may be topped-off up to the MAX fill level.

4. If brake system service was just completed, the brake fluid may be topped-off up to the MAX fill level.

5. If the brake fluid level is above the half way point, adding brake fluid is not recommended under normal conditions.

6. If brake fluid is to be added to the master cylinder reservoir, clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.

7. If necessary, add GM approved brake fluid from a clean, sealed brake fluid container. Refer to Adhesives, Fluids, Lubricants, and Sealers.

MASTER CYLINDER RESERVOIR REPLACEMENT

Removal Procedure

WARNING: Brake Fluid Irritant Warning

WARNING: Use of eye goggles is necessary to prevent personal injury. CAUTION: Brake Fluid Effects on Paint and Electrical Components Caution

1. Remove Dash Upper Extension Panel Opening Cover Replacement

2. Using a suitable tool, remove and properly dispose of the brake fluid from the brake master cylinder reservoir.

Fig. 9: Radiator Surge Tank And Bracket Clip Courtesy of GENERAL MOTORS COMPANY

3. Remove Clip(2)@Radiator Surge Tank (1)

4. Slide the radiator surge tank forward and lift to remove.

Fig. 10: Electrical Connector And Brake Fluid Level Sensor Courtesy of GENERAL MOTORS COMPANY

5. Disconnect Electrical Connector (2) @Brake Fluid Level Sensor (1)

Fig. 11: Brake Master Cylinder Reservoir And Body Wiring Harnes Courtesy of GENERAL MOTORS COMPANY

6. Unclip Clip (2)@Brake Master Cylinder Reservoir (3)

7. Unclip Clip (4) @Brake Master Cylinder Reservoir

8. Body Wiring Harness (1) @Brake Master Cylinder Reservoir

Fig. 12: Brake Master Cylinder Reservoir Hose Courtesy of GENERAL MOTORS COMPANY

NOTE: Cap the opening to prevent contamination.

9. Disconnect Brake Master Cylinder Reservoir Hose (2)

10. Remove Bolt (3) @Brake Master Cylinder Reservoir (1)

Fig. 13: Brake Master Cylinder Reservoir Courtesy of GENERAL MOTORS COMPANY

NOTE: Protect the windshield edge before removing the component.

11. Remove Brake Master Cylinder Reservoir (1) @Brake Master Cylinder (3)

12. Remove Brake Master Cylinder Reservoir Seal (2) @Brake Master Cylinder

13. Remove Brake Fluid Level Sensor Replacement

Installation Procedure

1. Install Brake Fluid Level Sensor Replacement

Fig. 14: Brake Master Cylinder Reservoir Courtesy of GENERAL MOTORS COMPANY

2. Lubricate the brake master cylinder reservoir seals with GM approved brake fluid from a clean, sealed,

brake fluid container. - Adhesives, Fluids, Lubricants, and Sealers

3. Install Brake Master Cylinder Reservoir Seal (2) @Brake Master Cylinder (3)

4. Install Brake Master Cylinder Reservoir (1) @Brake Master Cylinder

Fig. 15: Brake Master Cylinder Reservoir Hose Courtesy of GENERAL MOTORS COMPANY

5. Connect Brake Master Cylinder Reservoir Hose (2)

CAUTION: Fastener Caution

6. Install Bolt (3) @Brake Master Cylinder Reservoir (1) and tighten 2.5 N.m (22 lb in)

Fig. 16: Brake Master Cylinder Reservoir And Body Wiring Harnes Courtesy of GENERAL MOTORS COMPANY

7. Install Body Wiring Harness (1) @Brake Master Cylinder Reservoir (3)

8. Install Clip (2) @Brake Master Cylinder Reservoir

9. Clip (4) @Brake Master Cylinder Reservoir

Fig. 17: Electrical Connector And Brake Fluid Level Sensor Courtesy of GENERAL MOTORS COMPANY

10. Connect Electrical Connector (2) @Brake Fluid Level Sensor (1)

Fig. 18: Radiator Surge Tank And Bracket Clip Courtesy of GENERAL MOTORS COMPANY

11. Install the radiator surge tank into the bracket and slide rearward to secure.(1)

12. Install Clip (2) @Radiator Surge Tank

13. Install Dash Upper Extension Panel Opening Cover Replacement

14. Bleed the brake system. Hydraulic Brake System Bleeding

MASTER CYLINDER REPLACEMENT

Fig. 19: Master Cylinder

Courtesy of GENERAL MOTORS COMPANY

MASTER CYLINDER OVERHAUL

WARNING: Refer to Brake Fluid Irritant Warning .

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

Disassembly Procedure

Fig. 20: Identifying Brake Master Cylinder (Cross Sectional View) Courtesy of GENERAL MOTORS COMPANY

1. Remove the brake master cylinder from the vehicle. Refer to Master Cylinder Replacement.

2. Secure the mounting flange of the brake master cylinder in a bench vise so that the rear of the primary piston is accessible.

3. Clean the outside of the master cylinder reservoir on and around the reservoir cap prior to removing the cap and diaphragm.

4. Remove the reservoir cap and diaphragm from the reservoir.

5. Inspect the reservoir cap and diaphragm for the following conditions. If any of these conditions are present, replace the affected components.

Cuts or cracks

Nicks or deformation

6. Remove the master cylinder reservoir from the master cylinder. Refer to Master Cylinder Reservoir Replacement.

7. Using a smooth, round-ended tool, depress the primary piston (2) and remove the piston retainer.

8. Remove the primary piston assembly from the cylinder bore.

9. Plug the cylinder inlet ports and the rear outlet port. Apply low pressure, non-lubricated, filtered air into the front outlet port, in order the remove the secondary piston (1) with the primary (6) and secondary (5) seals, and the return spring.

10. Discard the primary piston assembly, the piston retainer, and the seals and seal retainer from the secondary piston.

Assembly Procedure

Fig. 21: Identifying Brake Master Cylinder (Cross Sectional View) Courtesy of GENERAL MOTORS COMPANY

NOTE: Do not use abrasives to clean the brake master cylinder bore.

1. Clean the interior and exterior of the master cylinder, the secondary piston (1), and the return spring in denatured alcohol, or equivalent.

2. Inspect the master cylinder bore, inlet and outlet ports, the secondary piston (1), and the return spring for cracks, scoring, pitting, and/or corrosion. Replace the master cylinder if any of these conditions exist.

3. Dry the master cylinder and the individual components with non-lubricated, filtered air.

4. Lubricate the master cylinder bore, the secondary piston (1), the return spring, and all of the individual overhaul components with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT - 3 brake fluid from a clean, sealed brake fluid container.

5. Assemble the lubricated, new primary seal (6) and retainer, and new secondary seal (5) onto the secondary piston.

6. Install the lubricated return spring and secondary piston assembly (1) into the cylinder bore.

7. Install the lubricated, new primary piston assembly (2) into the cylinder bore.

8. Using a smooth, round-ended tool, depress the primary piston (2) and install the new piston retainer.

9. Install the master cylinder reservoir to the master cylinder. Refer to Master Cylinder Reservoir Replacement.

10. Install the reservoir cap and diaphragm to the reservoir.

11. Install the master cylinder to the vehicle. Refer to Master Cylinder Replacement.

MASTER CYLINDER BENCH BLEEDING

Fig. 22: Bleeding Master Cylinder

Courtesy of GENERAL MOTORS COMPANY

WARNING: Refer to Brake Fluid Irritant Warning .

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

1. Secure the mounting flange of the brake master cylinder in a bench vise so that the rear of the primary piston is accessible.

2. Remove the master cylinder reservoir cap and diaphragm.

3. Install suitable fittings to the master cylinder ports that match the type of flare seat required and also

provide for hose attachment.

4. Install transparent hoses to the fittings installed to the master cylinder ports, then route the hoses into the master cylinder reservoir.

5. Fill the master cylinder reservoir to at least the half-way point with GM approved brake fluid from a clean, sealed brake fluid container. Adhesives, Fluids, Lubricants, and Sealers

6. Ensure that the ends of the transparent hoses running into the master cylinder reservoir are fully submerged in the brake fluid.

7. Using a smooth, round-ended tool, depress and release the primary piston as far as it will travel, a depth of about 25 mm (1 in), several times. Observe the flow of fluid coming from the ports.

As air is bled from the primary and secondary pistons, the effort required to depress the primary piston will increase and the amount of travel will decrease.

8. Continue to depress and release the primary piston until fluid flows freely from the ports with no evidence of air bubbles.

9. Remove the transparent hoses from the master cylinder reservoir.

10. Install the master cylinder reservoir cap and diaphragm.

11. Remove the fittings with the transparent hoses from the master cylinder ports. Wrap the master cylinder with a clean shop cloth to prevent brake fluid spills.

12. Remove the master cylinder from the vise.

BRAKE MASTER CYLINDER SHIELD REPLACEMENT

Removal Procedure

1. Remove Dash Upper Extension Panel Opening Cover Replacement

Fig. 23: Fuel Feed Hose

Courtesy of GENERAL MOTORS COMPANY

2. Disconnect Fuel Feed Hose (1) @Clip

Fig. 24: Radiator Surge Tank And Bracket Clip Courtesy of GENERAL MOTORS COMPANY

3. Remove Radiator Surge Tank Bracket Clip (2)

NOTE: Do NOT disconnect the engine coolant hoses.

4. Reposition away Radiator Surge Tank (1)

Fig. 25: Brake Master Cylinder Shield Courtesy of GENERAL MOTORS COMPANY

5. Disconnect the brake master cylinder shield (1) from the brake master cylinder assembly.

Installation Procedure

Fig. 26: Brake Master Cylinder Shield Courtesy of GENERAL MOTORS COMPANY

1. Connect the brake master cylinder shield (1) to the brake master cylinder assembly.

Fig. 27: Radiator Surge Tank And Bracket Clip Courtesy of GENERAL MOTORS COMPANY

2. Install Radiator Surge Tank (1)

3. Install Radiator Surge Tank Bracket Clip (2)

Fig. 28: Fuel Feed Hose

Courtesy of GENERAL MOTORS COMPANY

4. Install Fuel Feed Hose (1) @ Clip

5. Install Dash Upper Extension Panel Opening Cover Replacement

BRAKE FLUID LEVEL SENSOR REPLACEMENT

Removal Procedure

Fig. 29: Electrical Connector And Brake Fluid Level Sensor Courtesy of GENERAL MOTORS COMPANY

1. Disconnect Electrical Connector (2) @Brake Fluid Level Sensor (1)

Fig. 30: Brake Fluid Level Sensor And Brake Master Cylinder Reservoir Courtesy of GENERAL MOTORS COMPANY

2. Disconnect Brake Fluid Level Sensor (2) @Brake Master Cylinder Reservoir (1)

Installation Procedure

Fig. 31: Brake Fluid Level Sensor And Brake Master Cylinder Reservoir Courtesy of GENERAL MOTORS COMPANY

1. Connect Brake Fluid Level Sensor (2) @Brake Master Cylinder Reservoir (1)

Fig. 32: Electrical Connector And Brake Fluid Level Sensor Courtesy of GENERAL MOTORS COMPANY

2. Connect Electrical Connector (2) @Brake Fluid Level Sensor (1)

BRAKE AND ACCELERATOR PEDAL ASSEMBLY REPLACEMENT

Removal Procedure

1. High Voltage Disabling

2. Remove Accelerator Pedal Replacement

3. Remove Power Brake Master Cylinder Booster Assembly Replacement

4. Remove Instrument Panel Tie Bar Replacement

Fig. 33: Brake And Accelerator Pedal Assembly And Nuts Courtesy of GENERAL MOTORS COMPANY

5. Remove the 2 brake and accelerator pedal assembly nuts (1) from the brake and accelerator pedal assembly (2).

Fig. 34: Brake And Accelerator Pedal Assembly Courtesy of GENERAL MOTORS COMPANY

6. Remove the brake and accelerator pedal assembly (1) from the vehicle.

Installation Procedure

Fig. 35: Brake And Accelerator Pedal Assembly Courtesy of GENERAL MOTORS COMPANY

1. Install the brake and accelerator pedal assembly (1) to the vehicle.

Fig. 36: Brake And Accelerator Pedal Assembly And Nuts Courtesy of GENERAL MOTORS COMPANY

2. Install the 2 brake and accelerator pedal assembly nuts (1) to the brake and accelerator pedal assembly (2) and tighten to 22 N.m (16 lb ft).

3. Install Power Brake Master Cylinder Booster Assembly Replacement

4. Install Instrument Panel Tie Bar Replacement

5. Install Accelerator Pedal Replacement

6. High Voltage Enabling

BRAKE PIPE REPLACEMENT

Special Tools

CH-45405 Brake Pipe Flaring Kit

For equivalent regional tools, refer to Special Tools.

WARNING: Refer to Brake Fluid Irritant Warning .

WARNING: Always use double walled steel brake pipe when replacing brake pipes. The use of any other pipe is not recommended and may cause brake system failure.

Carefully route and retain replacement brake pipes. Always use the correct fasteners and the original location for replacement brake pipes. Failure to properly route and retain brake pipes may cause damage to the brake pipes and cause brake system failure.

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

NOTE: When servicing the brake pipes, note the following:

If sectioning the brake pipe, use replacement pipe of the same type and outside diameter.

Use fittings of the appropriate size and type.

Only create flares of the same type or design as originally equipped on the vehicle.

1. Inspect the area of brake pipe to be repaired or replaced.

2. Remove components as necessary to gain access to the brake pipe to be repaired or replaced.

3. Release the brake pipe to be replaced from the retainers, as required.

4. Select an appropriate location to section the brake pipe, if necessary.

Allow adequate clearance in order to maneuver the CH-45405 Brake Pipe Flaring Kit. Avoid sectioning the brake pipe at bends or mounting points.

5. Using a string or wire, measure the length of the pipe to be replaced including all pipe bends.

6. Add to the measurement taken the appropriate additional length required for each flare to be created.

Specification

6.35 mm (0.250 in) for 4.76 mm (3/16 in) diameter pipe

9.50 mm (0.374 in) for 6.35 mm (1/4 in) diameter pipe

12.67 mm (0.499 in) for 7.94 mm (5/16 in) diameter pipe

Fig. 37: Sectioning Brake Pipe Using Pipe Cutter Courtesy of GENERAL MOTORS COMPANY

NOTE: Ensure that the brake pipe end to be flared is cut at a square, 90 degree angle to the pipe length.

7. Using the pipe cutter included in the CH-45405 Brake Pipe Flaring Kit, carefully cut the brake pipe squarely to the measured length.

8. Remove the sectioned brake pipe from the vehicle.

9. Select the appropriate size of brake pipe and tube nuts, as necessary. The brake pipe outside diameter determines brake pipe size.

Fig. 38: Stripping Nylon Coating From Brake Pipe Ends Courtesy of GENERAL MOTORS COMPANY

10. Strip the nylon coating from the brake pipe end to be flared, if necessary.

Select the appropriate blade on the coating stripping tool included in the CH-45405 Brake Pipe Flaring Kit, by unthreading the blade block from the stripping tool and installing the block with the desired blade facing the tool rollers.

Specification

6.35 mm (0.250 in) blade for 4.76 mm (3/16 in) diameter pipe

9.50 mm (0.374 in) blade for 6.35 mm (1/4 in) and 7.94 mm (5/16 in) diameter pipe

Insert the brake pipe end to be flared into the stripping tool to the depth of the ledge on the tool rollers.

While holding the brake pipe firmly against the stripping tool roller ledges, rotate the thumbwheel of the tool until the blade contacts the brake pipe coated surface.

NOTE: Do not gouge the metal surface of the brake pipe.

Rotate the stripping tool in a clockwise direction, ensuring that the brake pipe end remains against the tool roller ledges.

After each successive revolution of the stripping tool, carefully rotate the thumbwheel of the tool clockwise, in order to continue stripping the coating from the brake pipe until the metal pipe surface is exposed.

Loosen the thumbwheel of the tool and remove the brake pipe.

NOTE: Ensure that all loose remnants of the nylon coating have been removed from the brake pipe.

Inspect the stripped end of the brake pipe to ensure that the proper amount of coating has been removed.

Specification

6.35 mm (0.250 in) for 4.76 mm (3/16 in) diameter pipe

9.50 mm (0.374 in) for 6.35 mm (1/4 in) and 7.94 mm (5/16 in) diameter pipe

Fig. 39: Chamfering Pipe Using De-Burring Tool Courtesy of GENERAL MOTORS COMPANY

11. Chamfer the inside and outside diameter of the pipe with the de-burring tool included in the CH-45405

Brake Pipe Flaring Kit.

12. Install the tube nuts on the brake pipe, noting their orientation.

13. Clean the brake pipe and the CH-45405 Brake Pipe Flaring Kit of lubricant, contaminants, and debris.

Fig. 40: Installing Die Halves Into Die Cage Courtesy of GENERAL MOTORS COMPANY

14. Loosen the die clamping screw of the CH-45405 Brake Pipe Flaring Kit.

15. Select the corresponding die set and install the die halves into the die cage with the full, flat face of one die facing the clamping screw, and the counterbores of both dies facing the forming ram.

Fig. 41: View Of Clamping Screw & Unused Die Courtesy of GENERAL MOTORS COMPANY

16. Place the flat face of an unused die (1) against the die halves in the clamping cage and hold firmly against the counterbored face of the dies.

17. Insert the prepared end of the pipe to be flared through the back of the dies until the pipe is seated against the flat surface of the unused die (1).

18. Remove the unused die (1).

19. Ensure that the rear of both dies are seated firmly against the enclosed end of the die cage.

20. Firmly hand tighten the clamping screw (2) against the dies.

Fig. 42: Rotating J 45405 To Bottom Against Die Cage Courtesy of GENERAL MOTORS COMPANY

21. Select the appropriate forming mandrel and place into the forming ram.

22. Rotate the hydraulic fluid control valve clockwise to the closed position.

23. Rotate the body of the CH-45405 Brake Pipe Flaring Kit until it bottoms against the die cage.

Fig. 43: Bottoming Forming Mandrel Against Clamping Dies Using Pipe Flaring Tool Courtesy of GENERAL MOTORS COMPANY

24. While guiding the forming mandrel into the exposed end of pipe to be flared, operate the lever of the

CH-45405 Brake Pipe Flaring Kit until the forming mandrel bottoms against the clamping dies.

25. Rotate the hydraulic fluid control valve counterclockwise to the open position to allow the hydraulic forming ram to retract.

Fig. 44: Using Pipe Flaring Tool

Courtesy of GENERAL MOTORS COMPANY

26. Insert the finishing cone into the forming ram.

27. Rotate the hydraulic fluid control valve clockwise to the closed position.

28. Rotate the body of the CH-45405 Brake Pipe Flaring Kit until it bottoms against the die cage.

29. While guiding the finishing cone into the exposed end of pipe to be flared, operate the lever of the

CH-45405 Brake Pipe Flaring Kit until the finishing cone bottoms against the dies.

30. Rotate the hydraulic fluid control valve counterclockwise to the open position to allow the hydraulic forming ram to retract.

31. Loosen the die clamping screw and remove the dies and pipe.

32. If necessary, lightly tap the dies until the die halves separate.

Fig. 45: Identifying Correct Brake Pipe Flare Shape & Diameter Courtesy of GENERAL MOTORS COMPANY

33. Inspect the brake pipe flare for correct shape and diameter (a).

Specification

6.74 - 7.10 mm (0.265 - 0.279 in) flare diameter for 4.76 mm (3/16 in) diameter pipe

8.57 - 9.27 mm (0.344 - 0.358 in) flare diameter for 6.35 mm (1/4 in) diameter pipe

10.42 - 10.79 mm (0.410 - 0.425 in) flare diameter for 7.94 mm (5/16 in) diameter pipe

34. If necessary, using the removed section of brake pipe as a template, shape the new pipe with a suitable brake pipe bending tool.

NOTE: When installing the pipe, maintain a clearance of 19 mm (3/4 in) from all moving or vibrating components.

35. Install the pipe to the vehicle with the appropriate brake pipe unions, as required.

36. If previously released, secure the brake pipe to the retainers.

37. Install any components that may have been removed to gain access to the brake pipe.

38. Bleed the hydraulic brake system. Hydraulic Brake System Bleeding

39. With the aid of an assistant, inspect the brake pipe flares for leaks by starting the engine and applying the brakes.

BRAKE MASTER CYLINDER RESERVOIR HOSE REPLACEMENT

Removal Procedure

WARNING: Brake Fluid Irritant Warning

CAUTION: Brake Fluid Effects on Paint and Electrical Components Caution

1. Remove Dash Upper Extension Panel Opening Cover Replacement

Fig. 46: Radiator Surge Tank And Bracket Clip Courtesy of GENERAL MOTORS COMPANY

2. Remove Radiator Surge Tank Bracket Clip (2)

NOTE: Do NOT disconnect the engine coolant hoses.

3. Reposition away Radiator Surge Tank (1)

Fig. 47: Brake Master Cylinder Reservoir And Hose Courtesy of GENERAL MOTORS COMPANY

NOTE: Cap the opening to prevent contamination.

4. Disconnect the brake master cylinder reservoir hose (2) from the brake master cylinder reservoir (1).

5. Remove Brake Pipe Fitting (3) @Brake Pressure Modulator Valve

6. Remove the brake master cylinder reservoir hose from the vehicle.

Installation Procedure

Fig. 48: Brake Master Cylinder Reservoir And Hose Courtesy of GENERAL MOTORS COMPANY

CAUTION: Fastener Caution

1. Install Brake Pipe Fitting (3) @Brake Pressure Modulator Valve and tighten 32 N.m (24 lb ft)

2. Connect the brake master cylinder reservoir hose (2) to the brake master cylinder reservoir (1).

Fig. 49: Radiator Surge Tank And Bracket Clip Courtesy of GENERAL MOTORS COMPANY

3. Install Radiator Surge Tank (1)

4. Install Radiator Surge Tank Bracket Clip (2)

5. Install Dash Upper Extension Panel Opening Cover Replacement

6. Hydraulic Brake System Bleeding

FRONT BRAKE HOSE REPLACEMENT

Removal Procedure

WARNING: Refer to Brake Fluid Irritant Warning .

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

1. Remove Tire and Wheel Removal and Installation

Fig. 50: Front Brake Hose And Brake Hose Fitting Bolt Courtesy of GENERAL MOTORS COMPANY

2. Remove Front Brake Hose (3) @Brake Hose Fitting Bolt (1)

3. Cap the brake hose fitting to prevent brake fluid loss and contamination.

4. Cap the brake caliper inlet port to prevent brake fluid loss and contamination.

5. DISCARD the brake hose fitting gaskets.(2)

Fig. 51: Front Brake Hose And Front Brake Pipe Fitting Courtesy of GENERAL MOTORS COMPANY

6. Remove Front Brake Hose (2) @Front Brake Pipe Fitting (1)

7. Cap the brake pipe fitting to prevent brake fluid loss and contamination.

8. Cap the brake hose fitting to prevent brake fluid loss and contamination.

Installation Procedure

1. Remove the caps from brake pipe fitting and the brake hose.

Fig. 52: Front Brake Hose And Front Brake Pipe Fitting Courtesy of GENERAL MOTORS COMPANY

CAUTION: Refer to Fastener Caution .

2. Install Front Brake Hose (2) @Front Brake Pipe Fitting (1) and tighten 20 N.m (15 lb ft)

3. Remove the caps from the brake hose and the brake caliper inlet port.

Fig. 53: Front Brake Hose And Brake Hose Fitting Bolt Courtesy of GENERAL MOTORS COMPANY

CAUTION: Refer to Fastener Caution .

4. Install NEW brake hose fitting gaskets.(2)

5. Install Front Brake Hose (3) @Brake Hose Fitting Bolt (1) and tighten 40 N.m (30 lb ft)

6. Hydraulic Brake System Bleeding

7. Install Tire and Wheel Removal and Installation - Install

REAR BRAKE HOSE REPLACEMENT

Fig. 54: Rear Brake Hose

Courtesy of GENERAL MOTORS COMPANY

HYDRAULIC BRAKE SYSTEM BLEEDING

WARNING: Refer to Brake Fluid Irritant Warning .

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

CAUTION: Only use products that comply with GM specifications and check manufacturer information respectively. We recommend the use of GM genuine products.

Instructions must be followed at all times. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.

If hydraulic components were serviced on only one wheel hydraulic circuit, perform the following procedure.

Bleeding a Single Hydraulic Brake Circuit

1. Place the Power button in the Service Only Mode.

2. Place a clean shop cloth beneath the brake master cylinder to catch brake fluid spills.

3. Clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.

4. Fill the brake master cylinder reservoir to the maximum-full level with GM approved brake fluid from a clean, sealed brake fluid container. Refer to Fluid and Lubricant Recommendations .

NOTE: The pressure bleeding equipment must be the diaphragm type. The rubber diaphragm between the air supply and the brake fluid prevents air, moisture, oil, and other contaminants from entering the hydraulic system.

5. Following the brake pressure bleeder manufacturer's instructions, fill the brake pressure bleeder with GM approved brake fluid from a clean, sealed brake fluid container.

6. Install the appropriate master cylinder reservoir adapter and connect the brake pressure bleeder.

7. Charge the brake pressure bleeder air tank to 170-200 kPa/1.7-2.0 bar (25-30 psi), or as recommended by the brake pressure bleeder manufacturer's instructions.

8. Open the brake pressure bleeder fluid tank valve to allow pressurized brake fluid to enter the brake

hydraulic system.

NOTE: Any brake fluid leaks identified require repair prior to completing this procedure.

9. Wait approximately 30 seconds, then inspect the entire hydraulic brake system for external brake fluid leaks.

10. Install a proper box-end wrench onto the wheel hydraulic circuit bleeder valve which has been serviced.

11. Install a transparent hose over the end of the bleeder valve.

12. Submerge the open end of the transparent hose into a transparent container partially filled with brake fluid from a clean, sealed brake fluid container.

13. Loosen the bleeder valve to purge air from the wheel hydraulic circuit.

14. Allow fluid to flow until air bubbles stop flowing from the bleeder.

15. After all air has been purged from the hydraulic circuit, tighten the bleeder valve and install the dust cap.

NOTE: The brake reservoir may have residual pressure after the bleeding operation is complete. Wrap a clean shop towel around the bleeder adapter and all hose connections before disconnecting the pressure bleeding equipment to prevent brake fluid from contacting and damaging vehicle components and painted surfaces.

16. Close the brake pressure bleeder fluid tank valve then disconnect the brake pressure bleeder from the master cylinder reservoir bleeder adapter.

17. Remove the master cylinder reservoir bleeder adapter from the master cylinder reservoir.

18. Fill the brake master cylinder reservoir to the maximum-fill level with GM approved brake fluid from a clean, sealed brake fluid container.

19. Slowly press and release the brake pedal. Observe the brake pedal feel.

20. If the brake pedal feels spongy, perform the Bleeding the Complete Brake Hydraulic System procedure:

21. Turn the ignition key ON, with the engine OFF. Check to see if the brake system warning lamp remains illuminated.

NOTE: DO NOT allow the vehicle to be driven until it is diagnosed and repaired.

22. If the brake system warning lamp remains illuminated, refer to Diagnostic Starting Point - Vehicle .

Bleeding the Complete Brake Hydraulic System

1. Place the Power button in the Service Only Mode.

2. Place a clean shop cloth beneath the brake master cylinder to catch brake fluid spills.

3. Clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.

4. Fill the brake master cylinder reservoir to the maximum-full level with GM approved brake fluid from a clean, sealed brake fluid container. Refer to Fluid and Lubricant Recommendations .

5. If the master cylinder was replaced, the master cylinder must be bench bled. Refer to Master Cylinder Bench Bleeding.

NOTE: The pressure bleeding equipment must be the diaphragm type. The rubber diaphragm between the air supply and the brake fluid prevents air, moisture, oil, and other contaminants from entering the hydraulic system.

6. Following the brake pressure bleeder manufacturer's instructions, fill the brake pressure bleeder with GM approved brake fluid from a clean, sealed brake fluid container.

7. Install the appropriate master cylinder reservoir adapter and connect the brake pressure bleeder.

8. Charge the brake pressure bleeder air tank to 170-200 kPa/1.7-2.0 bar (25-30 psi), or as recommended by the brake pressure bleeder manufacturer's instructions.

9. Open the brake pressure bleeder fluid tank valve to allow pressurized brake fluid to enter the brake hydraulic system.

NOTE: Any brake fluid leaks identified require repair prior to completing this procedure.

10. Wait approximately 30 seconds, then inspect the entire hydraulic brake system for external brake fluid leaks.

11. Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve.

12. Install a transparent hose over the end of the bleeder valve.

13. Submerge the open end of the transparent hose into a transparent container partially filled with GM approved brake fluid from a clean, sealed brake fluid container.

14. Loosen the bleeder valve to purge air from the wheel hydraulic circuit.

15. Allow fluid to flow until air bubbles stop flowing from the bleeder.

16. After all air has been purged from the hydraulic circuit, tighten the bleeder valve and install the dust cap.

17. Install a proper box-end wrench onto the LEFT REAR wheel hydraulic circuit bleeder valve, then repeat steps 12-16.

18. Install a proper box-end wrench onto the RIGHT FRONT wheel hydraulic circuit bleeder valve, then repeat steps 12-16.

19. Install a proper box-end wrench onto the LEFT FRONT wheel hydraulic circuit bleeder valve, then repeat steps 12-16.

20. Close the brake pressure bleeder fluid tank valve.

NOTE: The brake reservoir may have residual pressure after the bleeding operation is complete. Wrap a clean shop towel around the bleeder adapter and all hose connections before disconnecting the pressure bleeding equipment to prevent brake fluid from contacting and damaging vehicle components and painted surfaces.

21. Remove the brake pressure bleeding equipment from the vehicle.

22. Fill the brake master cylinder reservoir to the maximum-full level with GM approved brake fluid from a clean, sealed brake fluid container. Refer to Fluid and Lubricant Recommendations .

23. Slowly press and release the brake pedal. Observe the brake pedal feel.

24. If the brake pedal feels spongy, perform the following procedure.

1. If equipped with antilock brakes, install a scan tool and perform the Antilock Brake System

Automated Bleed to remove air which may be trapped in the BPMV.

2. Inspect the hydraulic brake system for external leaks. Refer to Brake System External Leak Inspection.

3. Repeat the Bleeding the Complete Brake Hydraulic System procedure.

25. If the brake pedal still feels spongy, pressure bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding.

26. Turn the ignition switch ON with the engine OFF. Check to see if the brake system warning lamp remains illuminated.

NOTE: DO NOT allow the vehicle to be driven until the brake system is diagnosed and repaired.

27. If the brake system warning lamp remains illuminated, refer to Diagnostic Starting Point - Vehicle .

HYDRAULIC BRAKE SYSTEM FLUSHING

WARNING: Refer to Brake Fluid Irritant Warning .

CAUTION: Refer to Brake Fluid Effects on Paint and Electrical Components Caution .

CAUTION: Only use products that comply with GM specifications and check manufacturer information respectively. We recommend the use of GM genuine products.

Instructions must be followed at all times. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.