For 1990-2009 cars

Caution: In order to avoid deploying the air bag when troubleshooting the SIR system, use only the equipment specified in this manual and the instructions given in this manual. Failure to use the specified equipment as instructed could cause air bag deployment, personal injury to you or someone else, or unnecessary SIR system repairs.

Caution: If any water enters the vehicle's interior up to the level of the carpet or higher and soaks the carpet, the sensing and diagnostic module (SDM) and the SDM harness connector may need to be replaced. The SDM could be activated when powered, which could cause deployment of the air bag(s) and result in personal injury. Before attempting these procedures, the SIR system must be disabled. Refer to Disabling the SIR System.

With the ignition OFF, inspect the SDM mounting area, including the carpet. If any significant soaking or evidence of significant soaking is detected, you must perform the following tasks:

1. Remove all water.
2. Repair the water damage.
3. Replace the SDM harness connector.
4. Replace the SDM.

Failure to follow these tasks could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs.

These diagnostic procedures will help you to find and repair SIR system malfunctions. This service category also contains information for repairing SIR system malfunctions. For best results, use the diagnostic tables, and follow the sequence listed below:

1. Perform the SIR Diagnostic System Check. All SIR diagnostics must begin with the SIR Diagnostic System Check. The SIR Diagnostic System Check determines the following:

• | Proper AIR BAG warning lamp operation

• | Existence of SIR Diagnostic Trouble Codes (DTC)

2. Refer to the diagnostic table as directed by the SIR Diagnostic System Check. The diagnostic tables will help enable you to diagnose any SIR system malfunction. Bypassing these procedures may result in the following:

• | Extended Diagnostic Time

• | Incorrect Diagnosis

• | Incorrect Parts Replacement

3. Repeat the SIR Diagnostic System Check 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.

### Circuit Description

The ignition switch supplies Ignition 1 voltage to the inflatable restraint Sensing and Diagnostic Module (SDM) connector C2 at terminal 3 using the IGN Fuse. The ignition switch also supplies an Accessory feed to the SDM connector C2 terminal 4 using the CIG Fuse. When the ignition switch is first turned to the ACC or ON position, the SDM responds by illuminating the AIR BAG warning lamp for approximately six seconds, then turning it OFF, while performing tests on the SIR system.

### Diagnostic Aids

You must diagnose the diagnostic trouble codes from the lowest number to the highest number. Failure to do so may result in the following:

• | Extended Diagnostic Time

• | Incorrect Diagnosis

• | Incorrect Parts Replacement

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Turn the ignition switch to OFF. Is the AIR BAG warning lamp illuminated? | -- | Go to AIR BAG Warning Lamp Circuit Malfunction | Go to Step 2
2 | Note the AIR BAG warning lamp as the ignition switch is turned to ON. Does the AIR BAG warning lamp illuminate steady for 6 seconds and then go OFF? | -- | System OK | Go to Step 3
3 | Display flash code DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying . Are there any DTCs displayed? | -- | Go to the appropriate DTC table | Go to Step 4
4 | Does the AIR BAG warning lamp flash continuously? | -- | Go to AIR BAG Indicator Flashes Continuously | Go to Step 5
5 |

1. Turn the ignition switch to the OFF position.
2. Intermittent DTCs are indicated. Refer to Diagnostic Aids for that specific DTC.

Are all DTCs diagnosed and malfunctions repaired?

--

Go to Step 1

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