Supplemental Inflatable Restraint (SIR)

Diagnostic Chart:

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 deployment loop. When the measured voltage is within a specified percentage of "Driver 36 VLR" power supply for 500 milliseconds DTC 35 is set.

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

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 above or below the percentage of "Driver 36 VLR" power supply voltage which sets DTC 35.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks for increased resistance of the RH forward discriminating sensor.
2. This test checks for an open in the ground feed to the RH forward discriminating sensor.
3. This test checks for increased resistance of the LH forward discriminating sensor.
4. This test checks for an open in the ground feed to the LH forward discriminating sensor.
5. This test checks for an open in the discriminating sensor interconnect circuit.
6. This test checks for a partial short inside the arming sensor.

DIAGNOSTIC AIDS
An intermittent condition is likely to be an improper connection at any of the discriminating sensor terminals, an open in either ground feed to the discriminating sensors, an open discriminating sensor interconnect circuit, increased resistance of either discriminating sensor or decreased resistance of the arming sensor.