Supplemental Inflatable Restraint (SIR)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
When the ignition switch is first turned "ON" battery voltage is applied to the "AIR BAG" warning lamp and to the "Ignition 1" input terminals "A9" and "A10." The DERM responds by flashing the "AIR BAG" warning lamp seven times alternating between the primary and redundant lamp drivers. The DERM monitors the redundant lamp driver output by comparing the output state at "SIR Indicator" terminal "B1" to the microprocessor commanded state. When "Ignition 1" is above a specified value and the output state does not match the commanded state of the redundant lamp driver for 400 milliseconds DTC 62 is set.

DTC WILL SET WHEN
"Ignition 1" voltage is above a specified value and the output state at the "SIR Indicator" terminal "B1" does not match the commanded state of the redundant lamp driver for 400 milliseconds during "Continuous Monitoring."

ACTION TAKEN
DERM attempts to turn "ON" the "AIR BAG" warning lamp using the primary lamp driver 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 circled number(s) on the diagnostic chart.
1. This test checks for an open in the "Redundant Indicator Ground" circuit.
2. This test checks for an open in the "Redundant Indicator Ignition I" circuit.

DIAGNOSTIC AIDS
An intermittent condition is likely to be caused by a poor connection to the DERM at terminal "A2" or "B2," an open in CKT 1590 or. an open in CKT 39A.