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

### Circuit Description

When you first turn the ignition switch to the ON position, the inflatable restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM monitors the voltages at DRIVER SIDE LOW terminal 9 to detect shorts-to-B+ in the inflator module circuits.

### Conditions for Setting the DTC

The SDM detects a short to battery voltage in the driver deployment loop.

### Action Taken When the DTC Sets

• | The SDM sets a Diagnostic Trouble Code.

• | The SDM turns ON the AIR BAG warning lamp.

### Conditions for Clearing the DTC

All DTCs are cleared with each ignition cycle.

### Diagnostic Aids

A short to B+ in the inflatable restraint steering wheel module circuit can cause an intermittent condition. Inspect the YEL/BLK and YEL wires leading to the steering wheel module carefully for cut or chafed wires.

### Test Description

1. This test checks for a short to voltage in the driver side high circuit.

2. This test determines if the malfunction is caused by the SDM.

3. This test determines if the malfunction is caused by the inflatable restraint steering wheel module.

4. This test checks for a short to voltage in the inflatable restraint steering wheel module coil.

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 OFF position.
2. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM).
3. Disconnect and remove the inflatable restraint steering wheel module from the steering column.
4. Turn the ignition switch to the ON position.
5. Measure the voltage at the steering wheel module coil connector C4 between terminal 1 and ground.

Is the voltage measured greater than the specified value?

0 V

Go to Step 5

Go to Step 3

3 |

1. Turn the ignition switch to the OFF position.
2. Connect the SDM.
3. Connect a jumper wire between terminals 1 and 2 of the steering wheel module coil connector C4.
4. Turn the ignition switch to the ACC or ON position and wait 20 seconds.
5. Clear SIR DTCs.
6. Turn the ignition switch to the ACC or ON position and wait 20 seconds.
7. Check for SIR DTCs.

Is DTC 12 present?

--

Go to Step 6

Go to Step 4

4 |

1. Turn the ignition switch to the OFF position.
2. Connect the steering wheel module connector.
3. Turn the ignition switch to ACC or ON and wait 20 seconds.
4. Clear SIR DTCs.
5. Turn the ignition switch to the ACC or ON position and wait 20 seconds.
6. Check for SIR DTCs.

Is DTC 12 present?

--

Go to Step 7

Go to Step 5

5 |

1. Disconnect the inflatable restraint steering wheel module coil connector C3 between the coil and the IP harness.
2. Measure the voltage from the steering wheel module coil connector C4 terminal 1 to ground.

Is the voltage measured greater than the specified value?

0 V

Go to Step 8

Go to Step 9

6 | Replace the inflatable restraint Sensing and Diagnostic Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Are all the repairs complete? | -- | Go to Step 10 | --
7 | Replace the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement . Are all the repairs complete? | -- | Go to Step 10 | --
8 | Replace the inflatable restraint steering wheel module coil. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement . Are all the repairs complete? | -- | Go to Step 10 | --
9 | Repair a short to voltage in the YEL/BLK wire between the steering wheel module coil and the SDM. Refer to Wiring Repair in this section. Are all the repairs complete? | -- | Go to Step 10 | --
10 | Reconnect all SIR components. Make sure all components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | Go to SIR Diagnostic System Check | --