Air Bag Systems: Description and Operation

The Supplemental Restraint System (SRS) supplements the driver and front passenger seat belts in a frontal collision and reduces the risk of death or serious injury. Three shock sensors, wired in series with the air bags and battery, are located in the air bag diagnostic unit (ADU) and at the front of each fender. If a crash of sufficient force occurs, the sensor contacts close and deploy the air bags.

Any faults or conditions detected by the SRS are stored in the ADU.

The SRS wiring harnesses are wrapped with yellow insulation for easy identification.

The air bag diagnostic unit receives its main power from the AIR BAG fuse and reserve power from the AUDIO fuse. Two collision sensitive sensors in the air bag diagnostic unit are in series with each other and with the battery and both air bag modules. When both sensors close simultaneously, squibs in both air bag modules will be initiated. The air bag diagnostic unit also contains a back-up power supply and a self-diagnostic function.