GM Service Manual Online
For 1990-2009 cars only

The body control module (BCM) produces four audible warnings to alert the driver of a system concern or a critical vehicle condition. If multiple audible warnings requests are received at the same time, the warning with the highest priority will sound first. The following lists the audible warning priority and pulse rate:

  1. Fast rate chime (150 pulses per min)
  2. Medium rate chime (100 pulses per min)
  3. Slow rate chime (50 pulses per min)
  4. Turn Signal reminder (will pulse @ turn signal flasher rate)

Fasten Safety Belt Warning

The body control module (BCM) senses that the driver's seat belt is not buckled and the signal is low. The BCM sends a class 2 message to the IPC requesting illumination of the seat belt indicator. The BCM seat belt chime sounds at the rate of 50 pulses per minute (slow rate chime) for a duration of approximately 6 seconds. The fasten safety belt warning sounds and the seat belt indicator illuminates when the following occurs:

    • Ignition switch transitions to ON.
    • The seat belt switch signal to the BCM is low.

If the seat belt is buckled when the ignition is turned on, the chime will not sound. If the seat belt is buckled while the chime is sounding, the chime stops.

Key-In-Ignition Warning

When the BCM detects the key is in the ignition and the signal is low with the driver door open, it activates an audible warning. The key-in-ignition chime sounds at the rate of 100 pulses per minute (medium rate chime) until the driver door is closed or the key removed from the ignition switch. The BCM activates the key-in-ignition warning when all of the following occurs:

    • The ignition switch is OFF.
    •  The key-in-ignition switch signal is low.
    • The driver door jamb switch signal is low with the driver door open.

Lights On Chime

The BCM will activate an audible warning as a reminder that the headlamps are left on when exiting the vehicle with the ignition switch in the OFF position. The lights on warning sounds at the rate of 150 pulses per minute (fast rate chime) until the headlamp switch in turned off. The BCM receives a signal from the headlamp and panel dimmer switch via the headlamp relay. The BCM activates the lights on warning chime when the following occurs:

    • The ignition is OFF.
    • The park lamp switch input is active.
    • The dimming potentiometer input is not in a maximum dimming state.

Turn Signal Warning

The BCM activates an audible warning as a reminder that the turn signal has been on for a distance of more than 1.20 km (0.75 mi). The BCM receives the vehicle speed and distance via the vehicle speed signal circuit. The turn signal chime will use a tone that is synchronized with the turn signal flasher. The BCM will activate the turn signal chime when the following occurs:

    • The ignition is ON.
    • Left or right turn signal switch is ON.
    • The vehicle has traveled further than 1.20 km (0.75 mi).

Park Brake Chime

The BCM activates the park brake chime when the park brake is engaged and the signal circuit is low and vehicle is driven for at least 3 seconds at a speed above 4.8 km (3 mph). The chime will sound at the rate of 150 pulses per minute (fast rate chime). The park brake indicator will flash for any distance the vehicle is driven every half second until the park brake is no longer engaged.