Circuit/System Description

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The K9 Body Control Module (BCM) provides low reference, signal, and reference voltage circuits to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will send a serial data message to the K219 Lighting Control Module requesting the brake lights on. The Lighting Control Module responds by apply battery voltage to the right and left stop lamp control circuits, and the center high mounted stop lamp control circuit. In addition to the serial data message from the BCM, the BCM also applies voltage to signal circuit 6311 to the K219 Lighting Control Module and K20 Engine Control Module. This circuit informs the modules that the brake pedal is being applied.