Park Brake Warning

The radio activates the park brake audible warning as requested by the body control module (BCM). The BCM sends a GMLAN message to the radio indicating the chime frequency (fast rate) and duration (continuous). The park brake warning sounds and the brake indicator illuminates when the following occurs:

• The ignition is ON.
• The vehicle speed is greater than 5 km/h (3.1 mph). The BCM receives a GMLAN message from the engine control module (ECM) indicating the vehicle speed.
• The BCM determines that the park brake is engaged (signal circuit is low).