Removal Procedure

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. 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: 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.