Circuit Description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. 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) performs tests to diagnose critical internal malfunctions. When SDM has completed power up mode, SDM will establish communication with Passenger Presence System (PPS). PPS will respond by performing diagnostic tests to check for proper circuit continuity and for shorts to ground or voltage with PPS. If PPS detects a malfunction, PPS will set a Diagnostic Trouble Code (DTC) and send a message to SDM, requesting that SDM disable passenger-side air bag module deployment loop.