Principles of Operation: Notes
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.
Refer to the following table for a summary of the chime characteristics including the chime priority.
| Chime Name | Priority | Number of Chime Tones |
|---|---|---|
| Safety belt | 1 | 6 |
| Air bag | 2 | 5 |
| Key-in-ignition | 3 | Until the key is removed or the driver door is closed. |
| Door ajar | 4 | 1 |
| Headlamps on | 5 | Until the headlamps are turned off or until the battery saver is activated. |
| Parking brake applied | 6 | Until the parking brake is released. |
| Belt minder | 7 | 24 |