GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Optra 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 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.

Upon passing this 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 deployment loops.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC 004 Driver Air Bag Deployment Loop Short To Voltage

Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

Conditions for Setting the DTC
    • The air bag wiring of the driver high is shorted to battery wiring.
    • The air bag wiring of the driver low is shorted to battery wiring.

Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

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.

Schematic Reference: SIR Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

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

Is there any visible damage to the SIR harness?

--

Go to Step 3

Go to Step 4

3

Replace the SIR wiring harness.

Did you complete the repair?

--

Go to Step 9

--

4
  1. Remove the steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
  2. Disconnect the electrical connector at the sensing and diagnostic module (SDM).

    3. The shorting bar at the disconnected SDM connector will create a complete circuit between the wires from the steering wheel module.

  3. Measure the voltage at one of the terminals on the wiring harness connector for the steering wheel module.

Does the voltage measure greater than the specified value?

0 V

Go to Step 7

Go to Step 5

5
  1. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  2. Connect the negative battery cable.
  3. Use the scan tool in order to clear the DTCs.
  4. Perform the Diagnostic System Check - Vehicle .

Is DTC 004 still shown as a current fault?

--

Go to Step 6

Go to Step 9

6

Replace the steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .

Did you complete the repair?

--

Go to Step 9

--

7
  1. Disconnect the steering wheel module coil 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 steering wheel module coil.

  2. Measure the voltage at one of the terminals on the SDM side of the steering wheel module coil connector.

Is the voltage equal to the specified value?

0 V

Go to Step 8

Go to Step 3

8

Replace the steering wheel module coil. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .

Did you complete the repair?

--

Go to Step 9

--

9
  1. Reconnect all SIR components.
  2. Verify that all components, connectors and connector position assurances (CPAs) are properly mounted.
  3. Use the scan tool in order to clear the DTCs.
  4. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK