GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC C0299 00:  Brake Booster Pressure Sensor Performance

DTC C0299 5A:  Brake Booster Pressure Sensor Performance Plausibility Failure

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Power Brake Booster High Control

C0299 00

C0299 00

C0299 00

C0299 5A

Power Brake Booster Low Control

--

C0299 00

C0299 00

C0299 5A

Circuit/System Description

The electronic brake control module (EBCM) provides power and ground circuits to the power brake booster actuator. The power brake booster actuator converts electrical inputs into a mechanical force to apply the brake booster to assist the driver as necessary in stability control. The EBCM monitors the vacuum level in the power brake booster, and will set a DTC if the vacuum is too low.

Conditions for Running the DTC

C0299 00

    • Ignition ON.
    • Ignition voltage is greater than10 volts.

C0299 5A

    • Ignition ON.
    • Engine Running.
    • Ignition voltage is greater than 10 volts.

Conditions for Setting the DTC

C0299 00

The EBCM detects a short to ground, open/high resistance or a short to voltage on the power brake booster actuator control circuits.

C0299 5A

    • No vacuum is detected in the power brake booster for approximately 10 seconds after start-up.
    • Low vacuum is detected in the power brake booster for approximately 60 seconds or longer after start-up, or is detected while driving.

Action Taken when the DTC Sets

    • The EBCM disables the active vacuum booster for the duration of the ignition cycle..
    • A DIC message and/or a warning indicator may be displayed.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present.
    • The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

ABS 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

C0299 00

  1. Ignition OFF, disconnect the harness connector from the power brake booster actuator.
  2. Test for less than 25k ohm of resistance between the harness connector terminal 5 and ground.
  3. If greater than 25k ohm, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the actuator harness connector terminal 1 and terminal 5.
  5. Ignition ON, command the Active Brake Booster to ON and OFF with a scan tool.
  6. If the test lamp remains OFF during the commands, test for a short to ground or an open/high resistance on either control circuit. If the circuits test normal, replace the electronic brake control module EBCM.
    If the test lamp is always ON, test the control circuits for a short to battery positive. If the circuit tests normal, locate and repair the source of the vacuum leak.
  7. If all circuits test normal, test or replace the vacuum brake booster assembly.
  8. If all circuits test normal, and no vacuum leaks were found, replace the electronic brake control module (EBCM).

C0299 5A

Verify DTC C0299 5A is not set.

If the DTC is set, repair the source of the vacuum leak. Refer to Brake Assist System Diagnosis

Component Testing

C0299 00

  1. Ignition OFF, disconnect the harness connector at the power brake booster actuator.
  2. Test for infinite ohms of resistance between the actuator terminal 1 and ground.
  3. If less than infinite ohms, replace the vacuum brake booster assembly.
  4. Test for 2-3 ohms of resistance between terminals 1 and 5 at the power brake booster actuator.
If the test is infinite resistance, replace the vacuum brake booster assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Power Vacuum Brake Booster Replacement
    •  Control Module References for EBCM replacement, setup, and programming