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 Descriptor

DTC C0299 00:  Brake Booster Pressure Sensor Performance

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Power Brake Booster High Control Circuit

C0299 00

C0299 00

C0299 00

--

Power Brake Booster Low Control Circuit

--

C0299 00

C0299 00

--

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

    • The ignition is ON.
    • Ignition voltage is greater than 9 volts.
    • The engine is running for the vacuum related fault to set.

Conditions for Setting the DTC

    • An open is detected on the high or low power brake booster actuator circuits.
    • A short to ground is detected on the high power brake booster actuator circuit.
    • A short to voltage is detected on the high power brake booster actuator circuit.
    • A short together in the high and low circuits is detected in the power brake booster actuator circuit.
    • A condition in which no vacuum is detected in the power brake booster for approximately 10 seconds after start-up.
    • A condition in which 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

    • One or more of the following actions may occur:
    • The SERVICE BRAKE BOOSTER will display on the Driver Information Center (DIC).

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present.
    • The EBCM automatically 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

Antilock Brake System 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

Scan Tool Data List for scan tool information

Circuit/System Verification

  1. DTC C0299 will set as result of power brake booster actuator or circuit failure, test for power, and ground circuits to the EBCM. These electrical failures will typically be set immediately after key-up.
  2. Test and repair the EBCM power or ground circuits if necessary.
  3. DTC C0299 will set as result of the power brake booster vacuum is too low. These will be set approximately 10 seconds or more after start-up, and may be intermittent.
  4. Locate and repair the source of the vacuum leak. Refer to Brake Assist System Diagnosis .

Circuit/System Testing

Important: It is recommend that Component Testing is performed before Circuit Testing when diagnosing the power brake booster actuator.

  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).

Component Testing

  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.

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