Circuit Description

When ignition is turned on, Sensing and Diagnostic Module (SDM) performs tests to diagnose critical internal malfunctions. Upon passing these tests, ignition and deployment loop voltages are measured to ensure they are within normal voltage ranges. During continuous monitoring diagnostics, a fixed amount of current flows in deployment loop. By monitoring voltage difference between passenger-side high and low circuits, SDM calculates combined resistance of passenger-side air bag, harness wiring circuits IB07 (Yellow/Green wire) and IB08 (Yellow/Red wire) and connector terminal contacts.