GM Service Manual Online
For 1990-2009 cars only

The radio or the chime module (UL5) produces four 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

Brake Warning

The IPC sends a class 2 message to the radio or the chime module (UL5) to activate an audible warning. The brake warning sounds and the brake indicator illuminates when the following occurs:

    • The vehicle speed is greater than 5 km/h (3.1 mph) and the park brake is engaged. The IPC will activate a fast rate chime until the park brake is disengaged.
    • A malfunction exists in the hydraulic brake system.
    • The rear brake boost (UJ1) switch signal circuit malfunction. The IPC will activate a fast rate chime at a continuous duration.

Key-In-Ignition Warning

The BCM sends a class 2 message to the radio or the chime module (UL5) to activate the key-in-ignition audible warning when the BCM 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 BCM sends a class 2 message to the radio or to the chime module to activate an audible warning as a reminder that the headlamps are ON when the 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 is 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

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 following warnings have an associated IPC indicator:

    • Engine Metal Hot
        The IPC sends a class 2 message to the radio or chime module (UL5) requesting a fast rate chime for a continuous duration. The IPC flashes the check gages indicator simultaneously with the engine hot metal chime warning.
    • Hot Coolant Temperature
        The IPC sends a class 2 message to the radio or chime module (UL5) requesting a fast rate chime for a duration of 4 pulses. The IPC solidly illuminates the check gages indicator and the hot coolant temperature chime warning sounds.
    • Low Fuel
        The radio or the chime module (UL5) activates the audible warning as requested by the IPC. The IPC sends a class 2 message to the radio or the chime module (UL5) requesting a medium rate chime for a duration of 4 pulses.

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