For 1990-2009 cars
SIR Components
SIR Schematics
SIR Caution
Handling ESD Sensitive Parts Notice

### Circuit Description

The ECU-B Fuse supplies battery voltage at all times to the AIR BAG warning lamp that is connected to the INFLATABLE RESTRAINT INDICATOR connector C2 terminal 2. When the ignition switch is turned to ACC or ON, battery voltage is applied to the inflatable restraint Sensing and Diagnostic Module (SDM) at connector C2 terminal 4. The SDM responds by illuminating the AIR BAG warning lamp for approximately six seconds while perfoming diagnostic tests on the SIR system. The IGN Fuse supplies battery voltage to the SDM at connector C2 terminal 3 when the ignition switch is in the ON or START positions.

### Test Description

1. This test checks for a short to ground in the SDM diagnostic terminal circuit.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | Go to SIR Diagnostic System Check
2 |

1. Turn the ignition switch to the LOCK position.
2. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM).
3. Measure the resistance between the SDM harness connector C2 terminal 15 and ground.

Is the resistance measured less than the specified value?

OL

(Infinite)

Go to Step 3

Go to Source Voltage Drop

3 | Repair the short to ground in the IP wiring harness between the Data Link Connector (DLC) and the SDM. Are all the repairs complete? | -- | Go to Step 4 | --
4 | Reconnect all the SIR components. Make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | Go to SIR Diagnostic System Check | --