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. SDM proceeds with resistance measurement test. Passenger-side low terminal No. 16 (Yellow/Red wire) is grounded through resistor and passenger current source connected to passenger-side high terminal No. 15 (Yellow/Green wire) allows a known amount of current to flow. 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.