GM Service Manual Online
For 1990-2009 cars only

The radio or the chime module (UL5) produces 4 audible warnings to alert the driver of a system concern or a critical vehicle condition. When 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--200 pulses per min
  2. Medium rate chime--150 pulses per min
  3. Medium/Slow rate chime--100 pulses per min
  4. Slow rate chime--50 pulses per min
  5. Turn Signal

Fasten Safety Belt Warning

The instrument panel cluster (IPC) sends a class 2 message to the radio or to the chime module (UL5) to activate the fasten safety belt warning when the seat belt indicator is activated. The seat belt chime sounds at the rate of 50 pulses per minute and will last for a duration of 5 pulses. The fasten safety belt warning is just a reminder to fasten the seat belt and does not monitor the seat belt status.

Key-In-Ignition Warning

The IPC sends a class 2 message to the radio or the chime module (UL5) to activate the key-in-ignition audible warning when the IPC detects that the key is in the ignition with the driver door open. The key-in-ignition chime sounds at the medium rate of 150 pulses per minute until the driver door is closed or the key is removed from the ignition switch.

Lights On Chime

The IPC sends a class 2 message to the radio or to the chime module (UL5) to activate an audible warning as a reminder that the headlamps are ON when door is open and the ignition switch is in the OFF position. The lights ON warning sounds at the fast rate of 200 pulses per minute until the headlamp switch in turned OFF.

Turning the park lamps OFF and turning it back ON with the driver door open will turn the chime OFF.

Turn Signal Warning

The turn signal audible warning will use a tone that is synchronized with the turn signal flasher. The IPC will activate the turn signal audible warning when the following occurs:

    • The ignition is ON.
    • Left or right turn signal switch is ON.

Vehicle Overspeed Warning (UD4)

The IPC sends a class 2 message to the radio or to the chime module (UL5) to activate the vehicle overspeed chime warning when the IPC detects that the vehicle speed is greater than 120 km/h (75 mph). The vehicle overspeed chime sounds at a medium rate of 150 pulses per minute and lasting for about 5 seconds

Additional Warnings

The IPC requests for audible warnings when certain IPC indicators are illuminated as an additional warning to alert the driver of a system concern or a critical vehicle condition. The IPC sends a class 2 message to the radio or chime module (UL5) to activate an audible warning when the following indicators are ON in the IPC:

    • Brake Lamp
        The brake lamp illuminates simultaneously with a chime warning only when there is a malfunction in the brake system.
    • Check Gages
    • Low Air
    • Low Coolant
    • Service Brake Lamp

For further information on the indicators and warning messages, refer to Indicator/Warning Message Description and Operation.