C0291

DTC C0291

Circuit Description
The park brake system uses a pair of solenoids to set or release the park brake pedal. These solenoids are powered by relays which are commanded ON and OFF by the body control module (BCM). When the gear shift lever is taken out of Park or Neutral, the BCM simultaneously activates both solenoids to release the park brake pedal. Solenoid A is deactivated after 2 seconds and solenoid B remains activated until the gear shift lever is in Park or Neutral, the engine is OFF, and the park brake switch is closed.

DTC Descriptor
This diagnostic procedure supports the following DTC.
DTC C0291 Park Brake Release Relay Circuit





This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description.

Conditions for Running the DTC
^ The ignition is ON.
^ Ignition voltage is greater than 8 volts.

Conditions for Setting the DTC

C0291 02
The BCM detects park brake relay B circuit is shorted to ground.

C0291 05
The BCM detects one of the following conditions:
^ The park brake relay B circuit is shorted to battery.
^ The park brake relay B circuit is open.

Action Taken When the DTC Sets
The ABS indicator turns ON.

Conditions for Clearing the DTC
^ The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
^ The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

DTC C0291 02
The park brake solenoid B circuit is shorted to ground.

DTC C0291 05
Possible causes of this DTC are the following conditions:
^ The park brake solenoid B circuit is shorted to voltage.
^ The park brake solenoid B circuit is open.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. Tests the park brake switch signal circuit. An open in the park brake switch of the park brake signal circuit will prevent release of the park brake and illumination of the red brake warning indicator.
3. Listen for an audible click when the park brake relay A operates. Command both the ON and OFF states. Repeat the commands as necessary.
4. Tests for voltage at the coil side of the park brake relay A.
5. Verifies that the BCM is providing ground to the park brake relay A.
6. Tests for voltage at the switch side of the park brake relay A. The PRK BRK fuse supplies power to the switch side of the park brake relay A.

Steps 1 - 3:

Steps 4 - 17:

DTC C0291