GM Service Manual Online
For 1990-2009 cars only

Circuit Description

In order to release the parking brake, the pump motor must supply fluid pressure to the actuator. When this pressure overcomes the spring tension inside of the actuator, the actuator piston moves, releasing the parking brake. The park brake pressure sensor monitors the fluid pressure whenever the ignition is ON.

Conditions for Running the DTC

    • The ignition is ON.
    • The parking brake applied.

Conditions for Setting the DTC

The parking brake pressure sensor detects an increase in system pressure when the parking brake is applied.

Action Taken When the DTC Sets

    • The SERVICE PARK BRAKE indicator turns ON.
    • Electro-hydraulic park brake function may be disabled.

Conditions for Clearing the DTC

The conditions for setting the DTC are no longer present and you use the procedure specified in Diagnostic Trouble Code (DTC) Clearing .

Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:

    •  Testing for Electrical Intermittents
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs
    •  Connector Repairs

Step

Action

Yes

No

Schematic Reference: Park Brake System Schematics

1

Did you perform the Park Brake Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Park Brake

2

  1. Engage the park brake.
  2. Observe the park brake pump motor.

Does the park brake pump motor continue to run?

Go to Park Brake Pump Motor Runs Continuously

Go to Park Brake Pressure Sensor Circuit Check