Sensing & Diagnostic Module (SDM)

WARNING: This page is about a different car, the 2002 Saturn Vue. 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 which are severe enough to warrant air bag module deployment. When a frontal collision of sufficient force is detected, SDM causes current to flow through driver-side and passenger-side air bag modules to deploy air bags. When a side collision of sufficient force occurs, SDM will trigger head impact air bag on side of impact. SDM also maintains a 23 Volt Loop Reserve (23 VLR) energy supply to provide deployment energy if battery voltage is lost during impact.

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.