Principles of Operation

PRINCIPLES OF OPERATION

The warning chimes are designed to provide the driver with an audio warning that acts as a supplemental alert. The only deviation from this strategy is the air bag chime which is used to alert the driver that the primary alerting system does not operate. The instrument cluster controls all warning chimes except for the belt minder, which is controlled by the restraint control module (RCM).

Each warning chime has unique characteristics that help to identify and differentiate each warning chime. The warning chimes use volume, chime frequency, length of time the chime sounds and the number of chime tones to identify which chime is sounding. The instrument cluster prioritizes the chimes according to a preset hierarchy programmed into the instrument cluster software. When more than one chime request is received by the instrument cluster, the most important chime sounds. If a lower priority chime is currently sounding, the higher priority request takes over and replaces the lower priority chime.

Instrument Cluster Chime Characteristics/Priority:

Refer to the table for a summary of the chime characteristics including the chime priority.

Safety Belt Warning Chime
The safety belt warning chime alerts the driver that the safety belt is unbuckled. The safety belt chime sounds when the driver safety belt is unbuckled and the ignition switch is turned from the OFF to the RUN or START position. The safety belt warning chime stops when the safety belt is fastened, when the ignition is switched to the OFF position or after the chime has sounded for 6 seconds.

Safety Belt Minder
The safety belt minder feature is configurable. Refer to Information Bus (Module Communications Network). To configure without using a scan tool, refer to Safety Belt Minder Deactivating/Activating. Service and Repair

The safety belt minder feature supplements the current driver safety belt warning function. The safety belt minder feature is enabled after the current safety belt warning is complete. The safety belt minder reminds the driver that the safety belt is unbuckled by intermittently sounding a chime and illuminating the safety belt warning indicator in the instrument cluster once the vehicle speed has exceeded 4.83 km/h (3 mph). While activated, the safety belt minder alternates the chime and the safety belt indicator from on for 6 seconds to off for 30 seconds.

Door Ajar Warning Chime
When any door is ajar and the ignition switch is in the RUN position, the door ajar warning indicator is activated and remains on until all doors are closed. A one second warning tone sounds once any time the key is in the ignition switch and any door is opened.

Headlamp On Warning Chime
The headlamp on warning chime alerts the driver that the headlamps or parking lamps are on, the key is not in the ignition lock cylinder, and the driver door is opened.

Key-in-Ignition Warning Chime
The key-in-ignition warning chime sounds when the driver door is opened with the key in the ignition lock cylinder, and the ignition switch is in the OFF or ACC position. It continues to sound until the key is removed from the ignition lock cylinder, or the driver door is closed.

Air Bag Warning Chime
A redundant warning chime is provided by the instrument cluster when the air bag warning indicator is not operational. The instrument cluster monitors the internal circuitry and bulb for the air bag warning indicator. If the instrument cluster receives an air bag warning indicator on request from the RCM and the instrument cluster detects a fault internally, the instrument cluster sets diagnostic trouble code (DTC) B1868 and sounds the chime.