SIR Diagnostic System Check

NOTE: If the vehicle interior has been exposed to extensive water intrusion such as water leaks, driving through high water, flooding, or other causes, the sensing and diagnostic module (SDM) and the SDM connector may need to be replaced. With the ignition OFF, inspect the area around the SDM, including the carpet. If any significant soaking or evidence of previous soaking is detected, the water must be removed, water damage repaired, and the SDM and SDM connector must be replaced. Before attempting any of these repairs, the supplemental inflatable restraint (SIR) system must be disabled. Refer to "Disabling the SIR System" and "Sensing and Diagnostic Module (SDM)" for instructions on how to disable the SIR system and replace the SDM.

The diagnostic procedures used are designed to find and repair SIR system conditions. To get the best results, it is important to use the diagnostic charts and follow the sequence listed below.

1. Perform the SIR Diagnostic System Check. The SIR Diagnostic System Check must be the starting point of any SIR diagnostics. The SIR Diagnostic System Check reveals diagnostic trouble codes through the use of a scan tool, and it also checks for proper AIR - BAG indicator operation.

2. Refer to the proper diagnostic chart as directed by the SIR Diagnostic System Check. The SIR Diagnostic System Check will lead you to the correct chart to diagnose any SIR system malfunctions. Bypassing these procedures may result in extended diagnostic time, incorrect diagnosis, and incorrect parts placement.

3. Repeat the SIR Diagnostic System Check after any repair or diagnostic procedures have been performed. Performing the SIR Diagnostic System Check after all repair or diagnostic procedures will ensure that the repair has been made correctly and that no other malfunctions exist.

Circuit Description
When the ignition switch is first turned to ON, Ignition 1 voltage is applied from the AIRBAG fuse to the sensing and diagnostic module (SDM) at input terminal A1. The SDM responds by flashing the AIRBAG indicator seven times and then turning it off while the SDM performs tests on the SIR system.

Diagnostic Aids
The order in which diagnostic trouble codes are diagnosed is very important. Failure to diagnose the DTCs in the order specified may result in extended diagnostic time, incorrect diagnosis and incorrect parts replacement.

Test Description
The number(s) refer to step(s) on the diagnostic table.

3. This test will identify the stored diagnostic trouble codes and whether they are current or history. A history DTC indicates that the malfunction has been repaired or is intermittent.
6. This test differentiates between an indicator that will not come on and an indicator that stays on when it should be off.
7. See the first caution below.
9. See the cautions below.
10. This test will determine whether history diagnostic trouble codes are stored and will identify them.
11. A history DTC indicates that the malfunction has been repaired or is intermittent.

Steps 1 - 7:

Steps 8 - 11:

SIR Diagnostic System Check

CAUTION: The SDM can maintain sufficient voltage to deploy the airbags for 10 minutes after the ignition is OFF and the fuse has been removed. If the air - bags are not disconnected, service cannot begin until 10 minutes have passed after disconnecting power to the SDM.

CAUTION: During service procedures, be very careful when handling the SDM. Never strike or jar the SDM.

Never power up the SIR system when the SDM is not rigidly attached to the vehicle. All SDM mounting bolts must be carefully tightened, and the SDM arrow must be pointing toward the front of the vehicle to ensure proper operation of the SIR system. The SDM could be activated if it is powered when it is not rigidly attached to the vehicle, resulting in unexpected deployment and possible injury.