Supplemental Inflatable Restraint (SIR)

Diagnostic Chart:

Diagnostic Chart (Cont'd):

Circuit Schematic:

CIRCUIT DESCRIPTION
When the ignition switch is turned On, the Sensing & Diagnostics Module (SDM) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests "Ignition 1," 36 VLR (Voltage Loop Energy Reserve), and deployment loop voltages are measured to ensure they are within their respective normal voltage ranges. The ADM then proceeds with the "Current Source Diagnostics." "Driver Side Low" terminal A2 is grounded through a resistor and the driver current source connected to "Driver Side High" terminal A1 allows a known amount of current to flow. By monitoring the voltage difference between "Driver Side High" and "Driver Side Low" the SDM calculates the combined resistance of the driver inflator module, SIR coil assembly, harness wiring circuits 347 and 348 and connector terminal contact.

DTC WILL SET WHEN:
The combined resistance of the driver inflator module, harness wiring circuits 347 and 348 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. "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 step number(s) on the diagnostic chart.
1. This test determines whether the malfunction is in the driver inflator module circuitry or in the SDM wiring harness circuitry.
2. This test checks whether the malfunction is due to high resistance in circuit 347.
3. This test checks whether the malfunction is in the driver inflator module or the SIR coil assembly.
4. This test checks whether the malfunction is due to high resistance in circuit 348.

DIAGNOSTIC AIDS:
An intermittent condition is likely to be caused by a poor connection at terminals A and B of the SIR coil connector at the base of the steering column, terminals A and B of the driver inflator module connector at the top of the steering column, SDM terminals A1 and A2 or a poor wire to terminal connection in circuit 347 or 348. The test for this diagnostic trouble code is only run while the AIR BAG warning lamp is performing the bulb check, unless DTC 17 or 26 is detected. When a Saturn Portable Diagnostic (Scan) (PDT) Tool "Clear Codes" command is issued and the malfunction is still present, the DTC will not reappear until the next ignition cycle.

Was the "SIR Diagnostic System Check" performed?

When measurements are requested in this chart, use (Saturn Tool) SA 91114NE DVM with correct terminal adapter from SA 92O6Z.