SIR System Overview

SIR System Overview:

The Supplemental Inflatable Restraint (SIR) system supplements the protection offered by the occupant seat belt system (2). The SIR system contains various inflator modules and seat belt pretensioners that are located throughout the vehicle, i.e. inflatable restraint steering wheel module (1), inflatable restraint IP module (1), inflatable restraint side impact module LF, inflatable restraint side impact module - RF, seat belt pretensioner - LF, and seat belt pretensioner - RF. Each inflator module and seat belt pretensioner has a deployment loop that is controlled by the Inflatable Restraint Sensing And Diagnostic Module (SDM), which is mounted inside of the vehicle. The SDM determines the severity of a collision and commands deployment of each inflator module and seat belt pretensioner. The SDM performs continuous diagnostic monitoring of the SIR system electrical components. Upon detection of a circuit malfunction, the SDM will set a Diagnostic Trouble (DTC) and inform the driver by commanding the Instrument Panel Cluster (IPC) to turn the AIR BAG indicator ON. The steering column and knee bolsters (3) are designed to absorb energy and compress during frontal collisions in order to limit leg movement and decrease the chance of injury to the driver and front passenger.