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 monitors voltage at driver-side low terminal No. 4 (Yellow/Black wire) and passenger-side low terminal No. 16 (Yellow/Red wire) to detect shorts to ground in air bag circuits.