GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Aveo 🢒 Restraints 🢒 SIR 🢒 DTC 004

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.

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 air bag wiring of driver high is shorted to battery wiring.
    • The air bag wiring of driver low is shorted to battery wire.

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

Visually inspect the supplemental inflatable restraint (SIR) harness for damage.

Is there any visible damage to the SIR harness?

--

Go to Step 3

Go to Step 4

3
  1. Replace the SIR wiring harness.
  2. Reconnect the negative battery cable.

Is your 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.

  5. Use a multimeter to measure the voltage at one of the terminals on the wiring harness connector for the driver air bag module.

Is the voltage greater than the specified value?

0 V

Go to Step 7

Go to Step 5

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 004 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 cable.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--

7
  1. Disconnect the clock spring wiring harness at the lower steering column.

    2. The shorting bar at the disconnected SDM connector will create a complete circuit between the wires from the clock spring.

  2. Using a multimeter, measure the voltage at one of the terminals on the SDM side of the clock spring connector.

Did the voltmeter indicate the specified value?

0 V

Go to Step 8

Go to Step 3

8
  1. Replace the clock spring.
  2. Reconnect the negative battery cable.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--