For 1990-2009 cars
SIR Components
SIR Schematics

### Circuit Description

When the ignition switch is first turned to the ON position, the IG-COIL METER fuse applies IGNITION 1 voltage to the AIR BAG warning lamp that is connected to the AIR BAG INDICATOR, terminal 7. The AIR BAG fuse applies system voltage to the IGNITION 1 input, terminal 8. The inflatable restraint Sensing and Diagnostic Module (SDM) responds by flashing the AIR BAG warning lamp seven times, which indicates that the SIR system is free from malfunctions. When the diagnostic request line is jumpered to ground, the SDM will flash the AIR BAG warning lamp in order to indicated if DTCs are present and, if so, what DTCs are present.

When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616 Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections . When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair in this section.

### Test Description

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

1. This test determines whether the malfunction is in the SDM circuitry or in the wiring.

#### Lamp Flashes Seven Times, Then DTC 12

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. Remove the AIR BAG Fuse.
3. Disconnect the inflatable restraint steering wheel and inflatable restraint IP modules yellow connectors located under the steering wheel side cap and behind the IP compartment.
4. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM)
5. Measure the resistance from the SDM harness connector terminal 12 to the SDM harness connector terminal 6 (Ground).

Is the reading less than the specified value?

OL

Go to Step 3

Go to Integrity Check

3 |

1. Repair the short to ground condition in the air bag diagnostic YEL/WHT wire between the SDM harness connector terminal 12 and the Air Bag Diagnostic Connector, located near the base of the steering column.
2. Install the AIR BAG Fuse.
3. Reconnect all the SIR system components and make sure all the components are properly mounted.

Have all the SIR components been reconnected and properly mounted?

--

Go to SIR Diagnostic System Check

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