Side Impact Air Bag System Description

Side Impact Restraint Devices (if Equipped):

The side impact air bag system supplements the protection offered by the driver door, the front passenger door, and the vehicle structure. The side impact air bag system deploys an air bag from the side of the driver or front passenger seat. A side crash of sufficient force will deploy a side air bag.

The side impact air bag system consists of the following components:
1. Two inflatable restraint Side Impact Sensors (SIS) (One in each front door)
2. Inflatable restraint driver seat module in the driver's seat
3. Inflatable restraint passenger seat module in the front passenger's seat
4. The AIR BAG Warning Lamp in the Instrument Panel Cluster (IPC)
5. Inflatable restraint sensing and diagnostic and seat belt pretensioner module (SDM)

The inflatable restraint side impact sensor (SIS), the inflatable restraint driver and passenger inflator modules, and the connecting wires make up the side impact deployment loops. The function of the side impact deployment loop is to supply current through the side impact inflator module, which will cause deployment of the side impact air bag. Deployment occurs when one of the SISs detects a side impact severe enough to warrant deployment.

The SIS contains a sensing device (accelerometer) that converts acceleration into an electrical (analog) signal. This signal is converted by a microprocessor in the SIS into acceleration and velocity data. This data is used by a sensing algorithm and compared to various predetermined boundary conditions. When the acceleration value exceeds the predetermined threshold, and the velocity boundary is crossed, the SIS will cause current to flow through the inflatable restraint driver module or the inflatable restraint passenger seat module.

The inflator modules consist of an inflatable bag and an inflator. An inflator consists of a canister of gas-generating material and an initiating device. The initiator is part of the deployment loop. When the vehicle is in a side impact crash of sufficient force, the inflatable restraint Side Impact Sensing Module (SISM) causes current to flow through the side impact air bag deployment loops. Current passing through the initiator ignites the material in the inflator module. The gas produced from this reaction rapidly inflates the air bag.

There is a shorting bar on each inflatable restraint side air bag module connector that connects to the SIR wiring harness. The shorting bar shorts across the inflatable restraint side air bag module circuits during the disconnection of the inflatable restraint side air bag module connector. The shorting of the inflatable restraint side air bag module circuitry will help prevent unwanted deployment of the air bag when servicing the inflatable restraint side air bag module, the seat or other SIR system components.