For 1990-2009 cars

### Circuit Description

The inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM) contains a sensing device which converts vehicle velocity changes to an electrical signal. The electrical signal detected is processed by the SDM and then compared to a value stored in memory. When the generated signal exceeds the stored value, additional signal processing is performed and the generated signals are compared to signals stored in memory. When two of the generated signals exceed the stored values, the SDM causes current to flow through the inflatable restraint steering wheel module, deploying the driver air bag and causing DTC 66 to set.

### Conditions for Setting the DTC

The inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM) detects a front crash, up to 30 degrees off the centerline of the vehicle, of sufficient force to warrant deployment of the air bags.

### Action Taken When the DTC Sets

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

• | The SDM records the Crash Data.

• | The SDM sets a diagnostic trouble code.

### Conditions for Clearing the DTC

The SDM is replaced.

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 General Electrical Diagnosis Procedures in Wiring Systems. When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair .

### Test Description

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

1. This test checks to see if the inflatable restraint steering wheel module has deployed.

2. This test checks for damage to the front of the vehicle and the undercarriage. If the inflatable restraint steering wheel module has not deployed and there are no signs of damage to the vehicle, the SDM may be malfunctioning.

#### DTC 66 Driver Air Bag Deployment Commanded

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 | Turn the ignition switch to the OFF position. Is the inflatable restraint steering wheel module deployed? | -- | Go to Step 3 | Go to Step 4
3 |

1. Replace the inflatable restraint steering wheel module. Refer to Steering Wheel Inflator Module Replacement in Steering Wheel and Column - Tilt.
2. Replace the driver seat belt side buckle pretensioner. Refer to Seat Belt Buckle Pretensioner Replacement - LH .
3. Replace the passenger seat belt side buckle pretensioner. Refer to Seat Belt Side Buckle Pretensioner Replacement - Pass. .
4. Replace the inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic and Seat Belt Pretensioner Module Replacement .
5. Refer to Repairs and Inspections Required After a Collision .
6. Clear the SIR Diagnostic Trouble Codes.

Are the SIR Diagnostic Trouble Codes cleared?

--

Go to SIR Diagnostic System Check

--

4 |

1. Inspect the front of the vehicle for signs of impact.
2. Inspect the undercarriage for signs of impact.

Are any signs of impact evident?

--

Go to Step 3

Go to Step 5

5 |

1. Turn the ignition switch to the OFF position.
2. Replace the inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic and Seat Belt Pretensioner Module Replacement .

Is the replacement complete?

--

Go to SIR Diagnostic System Check

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