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 SDM 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, SIR coil assembly, harness wiring circuits 347 and 348 and connector terminal contact is above a specified value. This test is run 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. DTC 16 and 22 will set simultaneously when the "Driver Side High" circuit is shorted to the "Passenger Side High" circuit due to parallel current paths.
3. This test determines whether the malfunction is in the driver inflator module circuitry or in the SDM wiring harness circuitry.
4. This test checks for a short from the "Driver Side High" circuits to the "Driver Side Low" circuit.
5. This test determines whether the malfunction is in the driver inflator module or the SIR coil assembly.
6. This test checks for a short from the "Driver Side High" circuit to the "Passenger Side Low" circuit.

DIAGNOSTIC AIDS:
An intermittent condition is likely to be caused by a short between circuit 347 and 348,1403 or 1404, or a malfunctioning shorting bar on the driver inflator module or SIR coil assembly which would require replacement of the component. 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 9206Z.