Side Impact Air Bag System Description

WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

The side impact air bag system consists of the following components:

2 Inflatable Restraint Side Impact Sensors (SIS) (1 in each B-pillar)
An Inflatable Restraint Side Impact Module - Left in the driver's seat
An Inflatable Restraint Side Impact Module - Right in the front passenger's seat
An AIR BAG Indicator in the Instrument Panel Cluster
An Inflatable Restraint Sensing and Diagnostic Module (SDM)

The inflatable restraint side impact sensor (SIS), the inflatable restraint side impact 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 SIS's 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 side impact module - left or the inflatable restraint side impact module - right.