Removal Procedure

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: The ignition must be in the OFF position, without pausing at ACCESSORY, and without applying the brake pedal to ensure the brake modulator and high pressure accumulator (HPA) pressure relief occurs. This process will take approximately 1 to 3 minutes.

Turn the ignition to OFF, without pausing at ACCESSORY, and without applying the brake pedal.
Remove the ignition key.
Wait approximately 1 to 3 minutes until the brake modulator and HPA pressure relief is complete.
Disconnect the brake master cylinder (BMC) primary piston position sensor electrical connector.

Fig 1: View Of Primary Piston Position Sensor

Courtesy of GENERAL MOTORS CORP.

Remove the 2 BMC primary piston position sensor screws (1).
Remove the primary piston position sensor (2).
Tilt the rear of the position sensor downward and remove the sensor.