GM Service Manual Online
For 1990-2009 cars only

Circuit Description

When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform a turn-on test to diagnose critical malfunctions within the SDM itself.

These test ignition and deployment loop voltages are measured to ensure that they are within their normal voltage ranges. The SDM monitors the voltages at the driver low and the passenger low to detect shorts to ground or voltage in the deploy loops.

If the resistance is in the 2-10 kilo ohms, the defect may occur depending upon the SDM. The normal resistance is over 10 kilo ohms.

Conditions for Setting the DTC

    • The air bag wiring of the 1st stage driver high is shorted to ground.
    • The air bag wiring of the 1st stage driver low is shorted to ground.

Step

Action

Values

Yes

No

Caution: Refer to Sensing and Diagnostic Module Handling Caution in the Preface section.

Caution: Refer to SRS Sensing and Diagnostic Module Handling Caution in the Preface section.

 

1

  1. Confirm the ignition switch is OFF and the sensing and diagnostic module (SDM) fuse has been removed.
  2. Wait for 1 minute to discharge the SDM charger.

Has the SDM discharged?

--

Go to Step 2

--

2

Visually inspect the connector and the wiring of the driver air bag.

Is the air bag wiring damaged?

--

Go to Step 6

Go to Step 3

3

  1. Confirm the ignition switch is OFF.
  2. Remove the driver air bag module.
  3. Disconnect the connector of the SDM wiring.
  4. Measure the resistance between the high, low wiring of the first stage driver air bag module and the ground.

Is the resistance equal to the specified value?

10 K ohms

Go to Step 4

Go to Step 5

4

  1. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  2. Confirm the ignition switch is ON.
  3. Erase the DTC using the scan tool.
  4. Perform the Diagnostic System Check-SIR.

Is the DTC removed?

--

Go to Diagnostic System Check - SIR

Go to Step 8

5

  1. Remove the connector from the clock spring wiring.
  2. Measure the resistance between the high, low wiring of the first stage clock spring and the ground.

Is the resistance at or above the specified value?

10 K ohms

Go to Step 7

Go to Step 6

6

Replace the air bag wiring.

Is the replacement complete?

--

Go to Diagnostic System Check - SIR

--

7

Replace the clock spring. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .

Is the replacement complete?

--

Go to Diagnostic System Check - SIR

--

8

Replace the driver air bag module. Refer to Inflatable Restraint Steering Wheel Module Replacement .

Is the replacement complete?

--

Go to Diagnostic System Check - SIR

--