Buick Regal: DTC C0299

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.
• Refer to Diagnostic Procedure Instructions for an overview of each diagnostic category.

DTC Descriptor

DTC C0299 56

Brake Booster Large Vacuum Leak Detected Too Many Transitions

Circuit/System Description

The brake booster vacuum sensor measures the vacuum in the brake booster assembly. The electronic brake control module supplies a 5 V reference and a low reference circuit to the brake booster vacuum sensor. The vacuum sensor supplies a voltage signal in relation to the pressure in the brake booster to the electronic brake control module.

Conditions for Running the DTC

Ignition ON.

Conditions for Setting the DTC

The EBCM detected a too low vacuum in the brake booster assembly for 120 s.

Action Taken When the DTC Sets

The brake warning indicator turns ON.

Conditions for Clearing the DTC

• A current DTC clears when the diagnostic runs and passes.
• The electronic brake control module will turn OFF the indicator in the next ignition cycle.

Reference Information

Schematic Reference

Hydraulic Brake Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Brake Assist System Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Refer to Control Module References.

Circuit/System Testing

1. Ignition ON.

2. Verify that DTC C025E is not set.

• If the DTC is set

Refer to DTC C025E.

• Go to next step: If the DTC is not set

3. Verify that the brake booster vacuum system has no damage, leakage or incorrect installation.

• If damage, leakage or incorrect installation is found

Refer to Brake Assist System Diagnosis.

• Go to next step: If the inspection is OK

4. Replace the B19B Brake Booster Vacuum Sensor.

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

• If the DTC sets

Replace the K17 Electronic Brake Control Module.

• Go to next step: If the DTC does not set

6. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Refer to Control Module References for Electronic Brake Control Module replacement, programming and setup.

DTC P050F

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.
• Refer to Diagnostic Procedure Instructions for an overview of each diagnostic category.

DTC Descriptor

DTC P050F

Brake Booster Weak Vacuum

For symptom byte information refer to Symptom Byte List.

Circuit/System Description

The brake booster vacuum sensor measures the vacuum in the brake booster assembly. The engine control module supplies a 5 V reference and a low reference circuit to the brake booster vacuum sensor. The vacuum sensor supplies a voltage signal in relation to the pressure in the brake booster to the engine control module.

Conditions for Running the DTC

• The vehicle is in an Autostop.
• No MAP sensor DTCs set.
• No TP sensor DTCs set.

Conditions for Setting the DTC

The engine control module detected a weak vacuum in the brake booster assembly.

Action Taken When the DTC Sets

DTC P050F is a Type B DTC.

Conditions for Clearing the DTC

DTC P050F is a Type B DTC.

Reference Information

Schematic Reference

Hydraulic Brake Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Brake Assist 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

Refer to Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify that DTCs P0556, P0557, or P0558 are not set.

• If the DTC is set

Refer to DTC P0556, P0557, or P0558.

• Go to next step: If the DTC is not set

3. Has the Brake Assist System Diagnosis been performed.

• If the Brake Assist System Diagnosis has not been performed

Refer to Brake Assist System Diagnosis.

• Go to next step: If the Brake Assist System Diagnosis has been performed

4. Test or replace the B19B Brake Booster Vacuum Sensor.

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

• If the DTC sets

Replace the K20 Engine Control Module.

• Go to next step: If the DTC does not set

6. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Refer to Power Brake Booster Vacuum Sensor Replacement (2.0L LTG) or Power Brake Booster Vacuum Sensor Replacement (3.6L LGX)
• Refer to Control Module References for K20 Engine Control Module replacement, programming and setup.

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