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 tests to diagnose any malfunctions within itself.

After passing these tests, the SDM will check the passenger air bag firing circuit. The SDM allows a very small amount of current to flow through the circuit. The SDM monitors the voltage during this check.

Conditions for Setting the DTC

The firing circuit is shorted to the voltage.

Step

Action

Values

Yes

No

Caution: Refer to Battery Disconnect Caution in the Preface section.

 

1

  1. Disconnect the battery negative cable.
  2. Wait 1 minute for the SDM capacitor to discharge.
  3. The capacitor supplies reserve power to deploy the passenger side air bag even if the battery has been disconnected.

  4. Visually inspect the supplemental inflatable restraints (SIR) wiring harness.

Is there any visible damage to the SIR wiring harness?

--

Go to Step 2

Go to Step 3

2

  1. Replace the SIR wiring harness.
  2. Reconnect the negative battery cable.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--

3

  1. Disconnect the electrical connector for the passenger air bag module.
  2. Disconnect the electrical connector at the SDM.
  3. The shorting bar at the disconnected SDM connector will create a complete circuit between the wires from the passenger air bag module.

  4. Use a multimeter to check the voltage at one of the terminals on the SDM side of the SIR wiring harness connector for the passenger air bag module. Refer to Diagnostic Illustration 10 in SIR Diagnostic Illustrations .

Is the voltage greater than the specified value?

0 V

Go to Step 2

Go to Step 4

4

  1. Replace the SDM.
  2. Reconnect the negative battery cable.
  3. Set the scan tool to CODE ERASE.
  4. Perform the diagnostic system check.

Does DTC 008 still show as a current fault?

--

Go to Step 5

System OK

5

  1. Replace the passenger side air bag module.
  2. Reconnect the negative battery cable.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--