General Description

The SIR system consists of the following components which make up the deployment loops:
^ AIR BAG warning lamp located in the instrument cluster.
^ Inflatable restraint front end discriminating sensor.
^ Inflatable restraint IP module.
^ Inflatable restraint sensing and diagnostic module (SDM)
^ Inflatable restraint steering wheel module.
^ Inflatable restraint steering wheel module coil.

The function of the deployment loops is to supply current through the inflator modules, which will cause deployment of the air bags. Deployment occurs when the SDM detects vehicle velocity changes severe enough to warrant deployment.

The SDM contains a sensing device (Accelerometer) that converts vehicle velocity changes to an electrical signal. The SDM compares this electrical signal to a value stored in memory. When the generated signal exceeds the stored value, the SDM performs additional signal processing and compares the generated signals to values stored in memory. When two of the generated signals exceed the stored values, the SDM will cause current to flow through the inflator modules, deploying the air bags. The inflatable restraint front end discriminating sensor assists the SDM in determining when a deployment should occur by providing an input signal to the SDM.