Description & Operation

WARNING: Accidental air bag deployment is possible. Personal injury may result. Read and follow all WARNINGS and AIR BAG SAFETY PRECAUTIONS before working on air bag system or related components.

The Supplemental Restraint System (SRS), also known as air bag system, is designed to provide increased accident protection for driver and front passenger by deploying driver-side and passenger-side air bags and seat belt pretensioners in a front-end collision. The air bag system is designed to work in conjunction with the 3-point seat belt system

The main components of the Air Bag System are the driver-side air bag module, contact coil (clockspring or SIR coil), passenger-side air bag module, Sensing and Diagnostic Module (SDM), driver-side and passenger-side seat belt pretensioners and AIR BAG warning light. The driver-side air bag module, passenger-side air bag module and seat belt pretensioners are deployed by current supplied from SDM through squib circuits. The current ignites an ignition compound which causes the generation of a large quantity of nitrogen gas to rapidly inflate the air bags or activate pretensioner piston.

The contact coil is combined with the combination switch assembly and is mounted on the steering column. It allows rotation of the steering wheel while maintaining continuous continuity of driver-side air bag module deployment loop. Sensing and Diagnostic Module (SDM) functions to detect velocity changes as a result of a frontal collision severe enough to warrant air bag and seat belt pretensioner deployment. The SDM also performs malfunction monitoring of the air bag system.