GM Service Manual Online
For 1990-2009 cars only

Circuit Description

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

The 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.

Conditions for Setting the DTC

The resistance of the driver air bag deployment loop is higher than 4.7 ohms.

Step

Action

Values

Yes

No

Caution: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Caution in the Preface section.

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

 

1

Perform the Diagnostic System Check - SIR.

Is the Diagnostic System Check - SIR complete?

--

Go to Step 2

Go to Diagnostic System Check - SIR

2

Examine the wiring and the connector at the driver air bag module.

Is the connector disconnected?

--

Go to Step 3

Go to Step 4

3

  1. Reconnect the driver air bag module connector.
  2. Reinstall the driver air bag module in the steering wheel.
  3. Reconnect the negative battery terminal.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--

4

  1. Disconnect the negative battery cable.
  2. Remove the driver air bag module.
  3. Place the driver air bag module in a secure position with the decorative surface facing upward.
  4. Disconnect the electrical connector at the sensing and diagnostic module (SDM).
  5. The shorting bar at the disconnected SDM connector will create a complete circuit between the wires from the driver air bag module.

  6. Connect an ohmmeter to the terminals of the wiring harness connector for the driver air bag module.

Does the ohmmeter indicate the specified value?

0 ohms

Go to Step 5

Go to Step 7

5

  1. Replace the SDM.
  2. Reconnect the negative battery cable.
  3. Set the scan tool for CODE ERASE.
  4. Perform the Diagnostic System Check - SIR.

Is DTC 001 still shown as a current fault?

--

Go to Step 6

System OK

6

  1. Replace the driver air bag module.
  2. Reconnect the negative battery terminal.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--

7

  1. Disconnect the clock spring wiring harness connector at the lower steering column.
  2. The shorting bar at the disconnected SDM connector will create a complete circuit between the wires from the driver air bag module.

  3. Connect an ohmmeter to the terminals at the SDM side of the clock spring connector.

Does the ohmmeter show the specified value?

0 ohms

Go to Step 8

Go to Step 9

8

  1. Replace the clock spring.
  2. Reconnect the negative battery terminal.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--

9

  1. Replace the supplemental inflatable resstraint (SIR) wiring harness.
  2. Reconnect the negative battery cable.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--