GM Service Manual Online
For 1990-2009 cars only

The audible warnings alert the driver of a system concern or a critical vehicle condition. The body control module (BCM) generates the audible warnings. The BCM receives audible warning requests via the class 2 serial data line or the CAN data line (L81). If the BCM receives multiple audible warning requests, the warning with the highest priority sounds first. The following lists the audible warning priority and the pulse rate:

  1. Fast rate chime--200 pulses per minute
  2. Medium rate chime--150 pulses per minute
  3. Slow rate chime--50 pulses per minute
  4. Single chime

Fasten Safety Belt Warning

The BCM activates the fasten safety belt audible warning as requested by the SDM. The SDM sends a class 2 message to the BCM. The fasten safety belt warning sounds and the fasten safety belt indicator illuminates when the following occurs:

    • The ignition switch transitions to ON.
    • The inflatable restraint sensing and diagnostic module (SDM) detects that the driver's seat belt is not buckled and or the signal is low. The BCM receives a class 2 message from the SDM indicating the driver's seat belt status.

If the seat belt is buckled when the ignition is turned ON, the chime does not sound. If the seat belt is buckled while the chime is sounding, the chime stops. If the seat belt is unbuckled after the initial transition to ON, the chime does not sound.

Key in Ignition Warning

The BCM monitors the signal circuit of the ignition switch. The BCM activates the key-in-ignition audible warning. The key-in-ignition warning sounds when the following occurs:

    • The ignition switch is OFF.
    • The body control module (BCM) determines that the driver's door is open and the signal circuit is low.
    • The BCM determines that the key-in-ignition switch is closed and the signal circuit is low.

Lights On Warning

The BCM activates the lights on warning. The BCM chimes a frequency of a fast rate and a continuous duration. The lights on warning sounds when the following occurs:

    • The ignition is OFF.
    • The BCM determines that the driver's door is open and the signal circuit is low.
    • The BCM determines that the headlamp switch is in the park or head position.

Park Brake Warning

The BCM activates the park brake audible warning. 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 class 2 message from the ECM/PCM indicating the vehicle speed.
    • The BCM determines that the park brake is engaged and the signal circuit is low.