Supplemental Inflatable Restraint (SIR)

Wiring Diagram:

CIRCUIT DESCRIPTION
During the "Turn-ON" tests, performed at the beginning of each ignition cycle, the DERM delays charging of the "Driver 36 VLR" terminal "A4" power supply. After the delay has expired the "Driver 36 VLR" power supply is allowed to charge. The DERM monitors the "Driver 36 VLR" power supply to ensure it has charged to a voltage above a specified value within 10 seconds after "Ignition 1" voltage is first applied to the DERM. When the "Driver 36 VLR" power supply does not reach the specified voltage within the allowed time or, once reaching the specified voltage, falls below it for 500 milliseconds, DTC 42 is set.

DTC WILL SET WHEN
The voltage measured at the "Driver 36 VLR" power supply does not exceed a specified value within 10 seconds afier "Ignition 1" voltage is first applied to the DERM or, once having reached the specified value, falls below the specified value 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 36 VLR" terminal "A4" is above a specified value for 500 milliseconds during "Continuous Monitoring."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks whether the diagnostic trouble code has set falsely.
2. This test checks whether a malfunctioning arming sensor is preventing the "Driver 36 VLR" from charging. This test will cause DTC 14 (Arming Sensor Disconnected) to set.
3. This test checks whether a short to B+ is preventing the "Driver 36 VLR" from charging.
4. This test checks whether a short to ground is preventing the "Driver 36 VLR" from charging.

DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a short from "Driver 36 VLR" to B+ or ground, or a short inside the arming sensor.