SIR System Overview

The supplemental inflatable restraint (SIR) system supplements the protection offered by the occupants Seat Belt System (2). The SIR system may contain several inflator modules located throughout the vehicle, i.e. steering wheel module (1), instrument panel module (1), or roof rail modules (1). In addition to inflator modules, the vehicle may contain seat belt pretensioners (2) that tighten the seat belt in the event of a collision, thus reducing the distance between the occupant and the seat belt when an inflator module is deployed. Each inflator module has a deployment loop that is controlled by the inflatable restraint sensing and diagnostic module (SDM) mounted inside the vehicle. The SDM determines the severity of a collision with the assistance of various sensor inputs located at strategic points on the vehicle. When the SDM detects a collision, it will process the information provided by the sensors to further support air bag or pretensioner deployment. The SDM will deploy the frontal air bags and pretensioners if it detects a collision of sufficient force. If the force of the impact is not sufficient to warrant inflator module deployment, the SDM may still deploy the seat belt pretensioners. The SDM performs continuous diagnostic monitoring of the SIR system electrical components. Upon detection of a circuit malfunction, the SDM will set a DTC and inform the driver by illuminating the AIR BAG indicator. The steering column (3) 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 passenger.
Deployment Outside Vehicle for Seat Belt Pretensioners
Frontal SIR System DescriptionHeadlamp Aiming Procedure
Open the hood.
Measure from the floor to the center of the headlamp bulb. Some
headlamps have an aim dot marked on the headlamp lens.
At the screen, measure from the floor and place the horizontal tape at
the measured distance.
Measure from the reference line on the floor to the le ...
Ultra High Strength Dual Phase Steel
This information provides repair recommendations and general guidelines for
steel classified as Ultra High Strength Dual Phase Steel (Dual
Phase Steel with a tensile strength greater than 800 MPa), also known as DPX.
General Motors recommends the following when repairing or replacing this type ...
Checking and Adding Power Steering Fluid
Caution: When adding fluid or making a complete fluid change, always
use the proper power steering fluid. Failure to use the proper fluid
will cause hose and seal damage and fluid leaks.
Clean the area surrounding the reservoir cap.
Remove the reservoir cap.
Inspect the power steeri ...