Supplemental Inflatable Restraint (SIR)

Diagnostic Chart:

Diagnostic Chart (Cont'd):

Circuit Schematic:

CIRCUIT DESCRIPTION
When the ignition switch is turned On, the Sensing & Diagnostics Module (SDM) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests "Ignition 1," 36 VLR (Voltage Loop Energy Reserve), and deployment loop voltages are measured to ensure they are within their respective normal voltage ranges. The ADM monitors the voltage at "Driver Side Low" and terminal A2 and "Passenger Side Low" terminal A6 to detect shorts in ground in the inflator module circuits.

DTC WILL SET WHEN:
The 36 VLR power supply in the SDM is in its normal operating voltage range and at least one of the two inflator modules is not open. Then, if the voltage measured at "Driver Side Low" and "Passenger Side Low" is below a specified value for 500 milliseconds, DTC 24 will set. This test is run during "Turn-On" tests and every 100 milliseconds during "Continuous Monitoring."

ACTION TAKEN:
SDM turns On the AIR BAG warning lamp and sets a diagnostic trouble code.

DTC WILL CLEAR WHEN:
The voltage measured at "Driver Side Low" and the voltage measured at "Passenger Side Low" are above specified value for 500 milliseconds.

DTC CHART TEST DESCRIPTION:
Number(s) below refer to step number(s) on the diagnostic chart.
1. This test determines whether the malfunction is occurring in the driver inflator module circuitry.
2. This test determines whether the malfunction is occurring in the passenger inflator module circuitry.
3. This test determines whether the malfunction is due to the
4. This test checks for a short from "Driver Side High" to ground.
6. This test checks for a short from "Driver Side Low" to ground.
8. This test checks for a short from "Passenger Side Low" to ground.
10. This test checks for a short from "Passenger Side High" to ground.

DIAGNOSTIC AIDS:
An intermittent condition is likely to be caused by a short to ground in the inflator module circuits. Inspect circuits 347, 348,1403 and 1404 carefully for cutting or chafing. If the wiring pigtail of the SIR coil assembly or passenger inflator module is damaged, the component must be replaced.

Was the "SIR Diagnostic System Check" performed?

When measurements are requested in this chart, use (Saturn Tool) SA 91114NE DVM with correct terminal adapter from SA 9206Z.