Circuit/System Verification

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: In order to avoid a misdiagnosis, perform the following:

If a BCM has been replaced, the brake pedal position (BPP) sensor must be calibrated. Refer to Brake Pedal Position Sensor Calibration .
Inspect for proper operation of the stop lamps. Refer to Exterior Lighting Systems Description and Operation .

Repair any brake system related DTCs before performing this diagnostic.

Ignition ON, observe the Stop Lamp Pedal Switch parameter in the PCM while applying and releasing the brake pedal. The reading should change between Applied/Released, and all brake lights should turn on and off accordingly.