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 PASSENGER SEAT LOW terminal 1 to detect shorts-to-B+ in the inflator module circuit.

### Conditions for Setting the DTC

The SDM detects a short to battery voltage in the passenger seat 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.

### Diagnostic Aids

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

### Test Description

1. This test checks for a short to voltage in the inflatable restraint passenger seat module high circuit.

2. This test checks for a short to voltage in the inflatable restraint passenger seat module low circuit.

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

4. This test determines if the malfunction is caused by the inflatable restraint passenger seat module.

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 inflatable restraint passenger seat module.
4. Turn the ignition switch to the ON position.
5. Measure the voltage at the seat module harness connector between terminal 1 and ground.

Is the voltage measured greater than the specified value?

0 V

Go to Step 8

Go to Step 3

3 | Measure the voltage at the seat module harness connector between terminal 2 and ground. Is the voltage measured greater than the specified value? | 0 V | Go to Step 9 | Go to Step 4
4 |

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 seat module connector.
4. Turn the ignition switch to the ACC or ON position and wait 20 seconds.
5. Turn the ignition switch to the OFF position in order to 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 42 present?

--

Go to Step 6

Go to Step 5

5 |

1. Turn the ignition switch to the OFF position.
2. Connect the seat module connector.
3. Turn the ignition switch to ACC or ON and wait 20 seconds.
4. Turn the ignition switch to the OFF position in order to 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 42 present?

--

Go to Step 7

Go to Step 10

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 11 | --
7 | Replace the inflatable restraint passenger seat module. Refer to Inflatable Restraint Seat Module Replacement - Passenger . Are all the repairs complete? | -- | Go to Step 11 | --
8 | Repair a short to voltage in the YEL/RED wire between the seat module and the SDM. Refer to Wiring Repair in Wiring Systems. Are all the repairs complete? | -- | Go to Step 11 | --
9 | Repair a short to voltage in the YEL/GRN wire between the seat module and the SDM. Refer to Wiring Repair in Wiring Systems. Are all the repairs complete? | -- | Go to Step 11 | --
10 | An intermittent exists in the passenger seat deployment loop. Refer to diagnostic aids. Are all the repairs complete? | -- | Go to Step 11 | --
11 | 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 | --