GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The inflatable restraint sensing and diagnostic and seat belt pretensioner module (SDM) receives a signal from the inflatable restraint side impact sensor (SIS) (LH) which contains a sensing device which converts air pressure changes in the driver door 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 driver seat module, deploying the driver side air bag and causing DTC 68 to set.

Conditions for Setting the DTC

The inflatable restraint sensing and diagnostic and seat belt pretensioner module (SDM) detects a side impact of sufficient force to warrant deployment of the driver side air bag.

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 DTC 68.

Conditions for Clearing the DTC

Current and History DTC codes must be cleared using a scan tool Clear DTC Information command. If the circuit fault has been successfully repaired and the conditions which caused the Current DTC 68 to set are no longer existing, History DTC 68 will set. History DTC 68 may be cleared using the scan tool. The SDM must be replaced after three pretensioner-only deployments or if Current DTC 68 cannot be cleared.

Test Description

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

  1. This test checks to see if the inflatable restriant driver seat module has deployed.

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

DTC 68 Driver Side 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.

Has the inflatable restraint driver seat module deployed?

--

Go to Step 3

Go to Step 4

3

  1. Replace the inflatable restraint driver seat module. Refer to Inflatable Restraint Seat Module Replacement - Driver .
  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 .
  3. Refer to Repairs and Inspections Required After a Collision .
  4. Use the scan tool to clear all current and history SIR DTCs.

Have all current and history SIR DTCs been cleared?

--

Go to SIR Diagnostic System Check

--

4

  1. Inspect the side 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 SDM. Refer to Inflatable Restraint Sensing and Diagnostic and Seat Belt Pretensioner Module Replacement .

Is the repair complete?

--

Go to SIR Diagnostic System Check

--