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 terminal 8 to calculate the combined resistance of the IP module and its associated wiring.

### Conditions for Setting the DTC

The SDM detects low resistance in the passenger 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.

### Test Description

1. This test checks for a short between the passenger side high and 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 inflatable restraint instrument panel 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 IP module.
4. Release the shorting bar on the SDM connector C2.
5. Measure the resistance at the IP module harness connector between terminal 1 and 2.

Is the resistance measured equal to the specified value?

OL

(Infinite)

Go to Step 3

Go to Step 7

3 |

1. Connect the SDM.
2. Turn the ignition switch to the ACC or ON position and wait 20 seconds.
3. Read SIR DTCs

Is DTC 53 present?

--

Go to Step 5

Go to Step 4

4 |

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

Is DTC 53 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 all repairs complete? | -- | Go to Step 9 | --
6 | Replace the inflatable restraint IP module. Refer to Inflatable Restraint Instrument Panel Module Replacement . Are all repairs complete? | -- | Go to Step 9 | --
7 | Repair the IP wiring harness between the IP module and the SDM. Refer to Wiring Repair . Are all repairs complete? | -- | Go to Step 9 | --
8 | An intermittent exists in the passenger deployment loop. Refer to diagnostic aids. Are all 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 | --