Frontal SIR System Description

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

The frontal SIR system consists of the following components:

AIR BAG indicator located in the instrument panel cluster (IPC).
Driver and passenger knee bolsters.
Inflatable restraint I/P module.
Inflatable restraint I/P module disable switch.
Inflatable restraint I/P module disable switch indicator.
Inflatable restraint sensing and diagnostic module (SDM).
Inflatable restraint steering wheel module.
Inflatable restraint steering wheel module coil.
Inflatable restraint wiring harnesses.
Steering wheel and column.

A frontal collision of sufficient force will deploy the frontal air bags. The SDM contains a sensing device that converts vehicle velocity changes to an electrical signal. The SDM also contains a microprocessor that performs calculations using the measured accelerations and compares these calculations to a value stored in memory. When the generated calculations exceed the stored value, the SDM will cause current to flow through the frontal deployment loops deploying the frontal air bags. Once the air bags are inflated they quickly deflate through the air bag vent holes and/or the bag fabric. After the air bags have deployed, the SDM sets a diagnostic trouble code (DTC) and turns the AIR BAG indicator ON. The SDM, I/P module, steering wheel module, steering wheel module coil and the connecting wires makeup the frontal deployment loops. The SDM continuously monitors the deployment loops for malfunctions and turns the AIR BAG indicator ON if a fault is detected.