Circuit Description
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
When ignition is turned on, Sensing and Diagnostic Module (SDM) compares restraints identification stored in SDM to restraints identification stored in Body Control Module (BCM). SDM will then compare Vehicle Identification Number (VIN) stored in SDM to VIN stored in Powertrain Control Module (PCM).