Supplemental Inflatable Restraint (SIR)

When measurements are requested in this chart, use SA 91114NE DVM with correct terminal adapter from SA 9206Z. When a check for proper connection is requested, refer to "Intermittents and Poor Connections." When a wire connector or terminal repair is requested, use the proper repair parts and refer to "Wiring Repair."

CAUTION: BEFORE PERFORMING DIAGNOSTICS, THE IGNITION SWITCH MUST BE IN THE "OFF" POSITION FOR 10 MINUTES (REFER TO DISABLING AND ENABLING PRECAUTIONS).

NOTICE: Perform "SIR DIAGNOSTIC SYSTEM CHECK" before proceeding with this chart. SIR Diagnostic System Check

CIRCUIT DESCRIPTION
When the ignition switch is turned On, the Sensing and Diagnostic Module (SDM) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests "Ignition 1," VLR, and deployment loop voltages are measured to ensure they are within their respective normal voltage ranges. The SDM then proceeds with the "Current Source Diagnostics. Passenger Side LO" terminal A4 is grounded through a resistor and the passenger current source connected to "Passenger Side HI" terminal Al allows a known amount of current to flow. By monitoring the voltage difference between "Passenger Side HI" and "Passenger Side LO" the SDM calculates the combined resistance of the passenger inflator module, harness wiring circuits 1403 and 1404 and connector terminal contact.

DTC WILL SET WHEN:
The combined resistance of the passenger inflator module, harness wiring circuits 1403 and 1404, and connector terminal contact is less than 1 ohm. This test is run once each ignition cycle during the "Current Source Diagnostic" when:
1. No "higher priority faults" are detected during "Turn-On."
2. No "higher priority faults" are detected during "Continuous Monitoring."
3. "Ignition 1" voltage is above a specified value.

ACTION TAKEN:
SDM turns On the AIR BAG telltale lamp and sets DTC 16.

DTC WILL CLEAR WHEN:
The malfunction is no longer occurring and the ignition switch is turned Off, or a Scan tool "Clear Codes" command is issued.

DTC CHART TEST DESCRIPTION:
Number(s) below refer to step number(s) on the diagnostic chart.
Step 1. DTC 16 and 22 will set simultaneously when the "Driver Side HI" circuit is shorted to the "Passenger Side HI" circuit due to parallel current paths.
Step 2. This test determines whether the malfunction is in the passenger inflator module circuitry or in the SDM wiring harness circuitry.
Step 4. This test checks for a short from the "Passenger Side HI" circuit to the "Passenger Side LO" circuit.
Step 6. This test checks for a short from the "Passenger Side HI" circuit to the "Driver Side LO" circuit.

DIAGNOSTIC AIDS:
An intermittent condition is likely to be caused by a short between circuit 1404, and circuit 347, 348, or 1403, or a malfunctioning shorting bar on the passenger inflator module which would require replacement of the module. The test for this diagnostic trouble code is only run while AIR BAG telltale lamp is performing the bulb check, unless DTC 17 or 26 is detected. When a Scan tool "Clear Codes" command is issued and the malfunction is still present, the DTC will not reappear until the next ignition cycle.