Supplemental Inflatable Restraint (SIR)

Wiring Diagram:

CIRCUIT DESCRIPTION
During normal, non-deployment operation of the SIR system, a small amount of current flows through the driver deployment loop. The diagnostic resistors within the arming sensor and the discriminating sensors, along with the resistance of the inflator module, cause voltage drops within the deployment loop. The DERM monitors the voltage at "Driver Side Low" terminal "B8" to detect shorts or opens within the driver deployment loop. When the measured voltage is above a specified percentage of "Driver 36 VLR" for 500 milliseconds, DTC 23 is set.

DTC WILL SET WHEN
The voltage measured at "Driver Side Low" terminal "B8" is above a specified percentage of "Driver 36 VLR" for 500 milliseconds during "Continuous Monitoring" and DTC 35 is not set.

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

DTC WILL CLEAR WHEN
The voltage measured at "Driver Side Low" terminal "B8" is within a specified percentage of "Driver 36 VLR" for 500 milliseconds during "Continuous Monitoring."

DTC TABLE TEST DESCRIPTION
Number(s) below refer to step number(s) on the diagnostic table.
1. The "SIR DIAGNOSTIC SYSTEM CHECK" must be the starting point for all diagnostics.
2. This test determines if the malfunction is due to a component or the wiring.
3. This test checks for a short from the "Driver 36 VLR" circuit to the "Driver Side Low" circuit.
5. This test checks for a short from the "Driver 36 VLR" circuit to the "Driver Side High" circuit.
6. This test determines where the short from "Driver 36 VLR" circuit to the "Driver Side High" circuit is located.
13. This test checks for an open between the driver inflator module and the discriminating sensor network.
16. This test determines where the open is located in CKT 348B.
19. This test checks for an open in the LH forward discriminating sensor between terminal "A" and terminal "B."
20. This test checks for a short inside the arming sensor.
23. This test checks for a short "Driver Side High" circuit to the "Driver Source Sense" circuit.
26. This test determines where the short from "Driver Side High" circuit to the "Driver Source Sense" circuit is located.
29. This test checks for a partial short inside the arming sensor.
32. This test checks for increased resistance of the Discriminating Sensor Intermediate Harness and/or the LH forward discriminating sensor.
37. This test checks for increased resistance of the LH forward discriminating sensor.
38. This test checks for increased resistance of the discriminating sensor intermediate harness and/or the RH forward discriminating sensor.
43. This test checks for increased resistance of the RH forward discriminating sensor.

DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by backed out/shorted terminals on the arming sensor harness connector or arming sensor jumper harness electrical connector poor connection at any of the discriminating sensor terminals, a short from CKT 236 to CKT 347 or CKT 348, a short from CKT 347 to CKT 1400, or an open or high resistance in CKT 348B.