Sensing & Diagnostic Module (SDM)

WARNING: This page is about a different car, the 2002 Pontiac Montana, 2002 Oldsmobile Silhouette, and 2002 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.

SDM monitors vehicle velocity changes to detect frontal or side collisions that are severe enough to warrant SIR system deployment. When a frontal collision of sufficient force is detected, SDM causes current to flow through air bag module and seat belt pretensioner deployment loops causing them to deploy. When a side impact of sufficient force is detected, SDM will cause side impact air bag module on side of impact to deploy. SDM maintains a 36 Volt Loop Reserve (36 VLR) energy supply to provide deployment energy for up to one minute after loss of ignition voltage.

Additionally, SDM provides diagnostic monitoring of SIR system electrical components. When a malfunction is detected, SDM sets a Diagnostic Trouble Code (DTC) which can be retrieved using a scan tool. SDM warns driver of system malfunctions by controlling AIR BAG warning light.