For 1990-2009 cars
SIR Components
SIR Schematics
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 LH PRETENSIONER LOW terminal 1 to calculate the combined resistance of the seat belt pretensioner and its associated wiring.

### Conditions for Setting the DTC

The SDM detects an open circuit or high resistance in the seat belt pretensioner deployment loop.

### Action Taken When the DTC Sets

• | The SDM sets a Diagnostic Trouble Code.

• | The SDM flashes the AIR BAG warning lamp.

### Conditions for Clearing the DTC

All DTCs are cleared with each ignition cycle.

### Test Description

1. This test checks for an open in the LH pretensioner high or low circuits.

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

3. This test determines if the malfunction is caused by the LH pretensioner.

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 the LH seat belt pretensioner.
4. Measure the resistance at the LH seat belt pretensioner harness connector between terminal 1 and terminal 2.

Is the resistance measured less than the specified value?

1 ohms

Go to Step 3

Go to Step 7

3 |

1. Connect the SDM.
2. Connect a jumper wire between terminals 1 and 2 of the pretensioner harness connector.
3. Turn the ignition switch to the ACC or ON position and wait 20 seconds.
4. Clear SIR DTCs.
5. Read SIR DTCs.

Is DTC 74 present?

--

Go to Step 5

Go to Step 4

4 |

1. Turn the ignition switch to the OFF position.
2. Connect the pretensioner connector.
3. Turn the ignition switch to ACC or ON and wait 20 seconds.
4. Clear SIR DTCs.
5. Read SIR DTCs.

Is DTC 74 present?

--

Go to Step 6

Go to Step 8

5 | Replace the inflatable restraint Sensing and Diagnostic Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Are the repairs complete? | -- | Go to Step 9 | --
6 | Replace the driver seat belt. Refer to Seat Belt Retractor Replacement - Left Front in Seat Belts. Are the repairs complete? | -- | Go to Step 9 | --
7 | Repair the IP wiring harness between the pretensioner and the SDM. Refer to Wiring Repair . Are the repairs complete? | -- | Go to Step 9 | --
8 | An intermittent exists in the driver seat belt deployment loop. Refer to diagnostic aids. Are the repairs complete? | -- | Go to Step 9 | --
9 | 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 | --