For 1990-2009 cars

Caution: If the vehicle interior is exposed to moisture and becomes soaked up to the level of the sensing and diagnostic module (SDM), the SDM and SDM harness connector must be replaced. The SDM could be activated when powered, which could cause airbag deployment and result in personal injury.

These diagnostic procedures will help you to find and repair SIR system malfunctions. For best results, use the diagnostic tables and follow the sequence listed below:

1. Refer to the diagnostic table as directed by a diagnostic system check - SIR. The diagnostic tables will help you to diagnose any SIR system malfunction. Bypassing these procedures may result in the following:

• | Extended diagnostic time

• | Incorrect diagnosis

• | Incorrect parts replacement

2. Repeat the diagnostic system check - SIR after you perform any repair or diagnostic procedures. This will verify that you correctly performed the repair. This will also ensure that no other malfunctions exist.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. Tests to see if the AIR BAG indicator flashes 7 times when the ignition is turned ON.

2. Tests to see if the scan tool powers up.

3. Tests to see if the scan tool can communicate with the inflatable restraint sensing and diagnostic module (SDM).

4. Tests to see if there are current or history diagnostic trouble codes (DTCs) present.

5. Tests to see if there are communication DTCs (U-codes) present.

6. Tests to see if DTC B1000 (ECU Malfunction) is present.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Note the AIR BAG indicator while turning ON the ignition. Does the AIR BAG indicator flash 7 times? | Go to Step 2 | Go to Symptoms - SIR
2 | Install a scan tool. Does the scan tool power up? | Go to Step 3 | Go to Scan Tool Does Not Power Up in Data Link Communications
3 | Attempt to establish communication with the SDM. Does the scan tool communicate with the SDM? | Go to Step 4 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications
4 |

1. Use the scan tool to request the SIR diagnostic trouble code (DTC) display.
2. Record the displayed DTC(s) on the repair order, specifying as current or history.

Does the scan tool display any current or history DTCs?

Go to Step 5

System OK

5 | Does the scan tool display any DTCs which begin with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | Go to Step 6
6 | Does the scan tool display DTC B1000? | Go to DTC B1000 in Body Control System | Go to Diagnostic Trouble Code (DTC) List