Stop Lamp Switch - Operation

OPERATION

The brake pedal position sensor monitors changes in the brake pedal position relative to the brake pedal mounting bracket. The sensor circuitry is energized by the Controller Antilock Brake (CAB) (also known as the Antilock Brake Module/ABM or Antilock Brake System/ABS module) and provides hard wired analog (potentiometer) inputs back to the CAB. The CAB uses the sensor inputs directly as additional logic for many of the Antilock Brake System (ABS), Electronic Stability Control (ESC) and Brake Assist System (BAS) features.

The CAB also sends electronic brake lamp switch status messages to other electronic modules in the vehicle over the Controller Area Network (CAN) data bus. Other electronic modules use this information as an additional logic input for controlling many other vehicle functions and features, including the Body Control Module (BCM) (also known as the Common Body Controller/CBC) for control of the brake (or stop) lamps.

The hard wired circuits between the brake pedal position sensor and the CAB may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the brake pedal position sensor or the electronic controls and communication that provide some features related to brake pedal position sensor operation. The most reliable, efficient and accurate means to diagnose the brake pedal position sensor or the electronic controls and communication related to sensor operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.