Supplemental Inflatable Restraint (SIR)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
When the ignition switch is turned "ON," the SDM will perform tests to diagnose critical malfunctions within itself. Upon passing these tests "Ignition 1," 36 VLR, and deployment loop voltages are measured to ensure they are within their respective normal voltage ranges. The SDM then proceeds with the "Current Source Diagnostics." "Passenger Side Low" terminal "A5" is grounded through a resistor and the passenger current source connected to "Passenger Side High" terminal "A6" allows a known amount of current to flow. By monitoring the voltage difference between "Passenger Side High" and "Passenger Side Low" the SDM calculates the combined resistance of the passenger inflator module, harness wiring CKTs Y/R and Y and connector terminal contact.

DTC WILL SET WHEN
The combined resistance of the passenger inflator module, harness wiring CKTs Y/R and Y, and connector terminal contact is above a specified value. This test is run once each ignition cycle during the "Current Source Diagnostics" when: 1) No "higher priority faults" are detected during "Turn-ON," 2) No "higher priority faults" are detected during "Continuous Monitoring," 3) No "Crank" signal present, 4) "Ignition 1" voltage is above a specified value.

ACTION TAKEN
SDM turns "ON" the "AIR BAG" warning Lamp and sets a diagnostic trouble code.

DTC WILL CLEAR WHEN
The ignition switch is turned "OFF."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test determines whether the malfunction is in the passenger inflator module circuitry or in the SDM wiring harness circuitry.
2. This test checks whether the malfunction is due to high resistance in CKT Y/R.
3. This test checks whether the malfunction is due to high resistance in CKT Y.

DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor connection at the passenger inflator module harness connector terminals "A" and "B," SDM terminals "A5" and "A6," or a poor wire to terminal connection in CKT Y/R or CKT Y. This test for this diagnostic trouble code is only run while the "AIR BAG" warning lamp is performing the bulb check, unless DTC 17 or DTC 26 is detected. When a scan tool "Clear Codes" command is issued and the malfunction is still present, the DIC will not reappear until the next ignition cycle.