Supplemental Inflatable Restraint (SIR)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
The deployment loops consist of the driver Inflator module, passenger Inflator module, SRS coil assembly, center sensor assembly and associated wires. The center sensor assembly supplies a small amount of current through the deployment loops, D CKT terminals B3 and B4 and P CKT terminals B1 and B2. By monitoring the voltage at these two circuits the center sensor assembly determines the combined resistance of the Inflator modules, SRS coil assembly and their respective wiring.

FAILURE CONDITIONS
DTC 12 will set if the center sensor assembly detects a short to B+ in the deployment loops.

ACTION TAKEN
The center sensor assembly will illuminate the AIR BAG indicator and open the safety circuit, disabling the SRS.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test determines whether the fault is in the passenger inflator module.
2. This test determines whether the fault is in the steering column components or in the SRS circuitry.
3. This test checks for a short to B+ in the D+ CKT.
4. This test determines whether the steering column fault is due to a faulty SRS coil assembly or a faulty driver inflator module.
5. This checks for a short to B+ in the D-CKT
6. This test checks for a short to B+ in the P+ CKT.
7. This lest determines if the fault is due to a short to B+ in the P-CKT or a faulty center sensor assembly.