Frontal SIR System Description
The frontal Supplemental Inflatable Restraint (SIR) System consists of the following components:
- AIR BAG indicator located in the instrument panel cluster (IPC)
- Inflatable restraint instrument panel (I/P) module
- Inflatable restraint sensing and diagnostic module (SDM)
- Inflatable Restraint Passenger Presence System (PPS)
- Inflatable restraint Passenger AIR BAG ON/OFF indicator
- Inflatable restraint steering wheel module
- Inflatable restraint steering wheel module coil
- Steering wheel and column
- Inflatable restraint front end sensor
- Inflatable restraint vehicle rollover sensor
- Inflatable restraint seat belt retractor pretensioners
- Inflatable restraint wiring harnesses
- Driver and passenger knee bolsters
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. In the event of a frontal collision, the SDM receives a signal from the electronic frontal sensor which assists the SDM in determining the severity of the collision. The SDM compares these signals to a value stored in memory. When the generated signals exceed the stored value, the SDM will cause current to flow through the frontal deployment loops simultaneously deploying the frontal air bags. The SDM, I/P module, steering wheel module, steering wheel module coil, seat belt pretensioner 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.