Frontal SIR System Description

The frontal SIR system consists of the following components:
^ AIR BAG warning lamp located in the Instrument Panel Cluster (IPC).
^ 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 inflatable restraint sensing and diagnostic module (SDM), inflatable restraint steering wheel module Coil, inflatable restraint steering wheel module, inflatable restraint IP module, and the connecting wires make up the frontal deployment loops. The function of the frontal deployment loops is to supply current through the frontal inflator modules, deploying the frontal inflator modules simultaneously. 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 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 frontal inflator modules deploying the frontal air bags.

The inflatable restraint front end discriminating sensor assists the SDM in determining when a frontal deployment should occur by providing an input signal to the SDM.