GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The driver deployment loop consists of the following components:

    • A dual-stage inflatable restraint steering wheel module
    • The inflatable restraint steering wheel module coil
    • The steering wheel module high circuits for both stages 1 and 2
    • The steering wheel module low circuits for both stages 1 and 2

There are 2 shorting bars used within the steering wheel module coil connector. These shorting bars short together both stages of the steering wheel module high circuit, and the steering wheel module low circuit when the connector is disconnected. This helps prevent unwanted deployment of the inflator module during servicing. During a frontal crash of sufficient force the inflatable restraint sensing and diagnostic module (SDM) will allow current to flow through the deployment loop. This flow of current will deploy the steering wheel module. The SDM performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC B0022 Left Front/Driver Frontal Deployment Loop (single stage or stage 1) Resistance Low
    • DTC B0024 Left Front/Driver Frontal Deployment Loop (single stage or stage 1) Voltage Out of Range
    • DTC B0026 Left Front/Driver Frontal Deployment Loop (single stage or stage 1) Open
    • DTC B0042 Left Front/Driver Frontal Deployment Loop (stage 2) Resistance Low
    • DTC B0043 Left Front/Driver Frontal Deployment Loop (stage 2) Voltage Out of Range
    • DTC B0044 Left Front/Driver Frontal Deployment Loop (stage 2) Open

Conditions for Running the DTC

Ignition 1 voltage is within the normal operating voltage range.

Conditions for Setting the DTC

    • DTC B0022 (stage 1) or B0042 (stage 2) will set when the steering wheel module deployment loop resistance is less than 1.3 ohms for 500 milliseconds.
    • DTC B0024 (stage 1) or B0043 (stage 2) will set when one of the following conditions occur:
       - The steering wheel module high circuits and/or low circuits is short-to-ground, or short-to-voltage for 500 milliseconds.
       - The steering wheel module high circuit is less than 2.4 volts and steering wheel module deployment loop resistance is less than 6 ohms for 500 milliseconds.
    • DTC B0026 (stage 1) or B0044 (stage 2) will set when one of the following conditions occurs:
       - The steering wheel module high circuit is less than 2.4 volts and the steering wheel module deployment loop is more than 6 ohms for 500 milliseconds.
       - The steering wheel module deployment loop resistance is more than 4.8 ohms for 500 milliseconds.

Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON via Class 2 serial data.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC is not currently present and the scan tool Clear DTCs function is used.
    • A history DTC will clear once 255 malfunction-free ignition cycles have occurred.

Diagnostic Aids

The following conditions are possible causes of the malfunction:

    • A short between the steering wheel module stage 1 or stage 2, high and low circuits.
    • An open or a high resistance in the steering wheel module stage 1 or stage 2, high or low circuits.
    • A short-to-ground, or a short-to-voltage in the steering wheel module stage 1 or stage 2, high circuits or low circuits.
    • A malfunctioning steering wheel module coil connector
    • A malfunctioning SDM connector
    • A malfunctioning steering wheel module
    • A malfunctioning steering wheel module coil
    • A malfunctioning SDM

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Tests if the malfunction is caused by the steering wheel module or by the steering wheel module coil.

  2. Determines which DTCs are present. If DTC B0022 or B0042 is present, test the steering wheel module for a short between high and low circuits in stage 1 or stage 2. If DTC B0024 or B0043 is present, test the steering wheel module high and low circuits for an open and for high resistance in stage 1 or stage 2. If DTC B0026 or B0044 is present, test the steering wheel module high and low circuits for an open and for high resistance in stage 1 or stage 2.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

Connector End View Reference: SIR Connector End Views

1

Did you perform a Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn OFF the ignition.
  2. Disconnect the steering wheel module coil in-line connector. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .
  3. Inspect the component and harness sides of the in-line connector for the steering wheel module coil for damage or corrosion that may cause the malfunction. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Does connector exhibit any signs of damage or corrosion?

Go to Step 3

Go to Step 4

3

  1. If the in-line connector for the steering wheel module coil is damaged, the steering wheel module coil must be replaced. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .
  2. If the wiring harness side of steering wheel module coil in-line connector is damaged, replace the harness side of the connector. Refer to Connector Repairs .

Did you complete the repair?

Go to Step 11

--

4

    Important: When installing J 38715-A SIR Driver/Passenger Load Tool for testing the dual stage steering wheel module, the correct 4-way load tool adapter connector must be used. Failure to use the correct 4-way load tool connector will set additional codes when testing.

  1. Use J 38715-80 Adapter to connect the J 38715-A to the harness side of the steering wheel module coil connector. Use BASE OF COLUMN and PASSENGER INFLATOR connectors.
  2. Turn ON the ignition, with the engine OFF.
  3. Use the scan tool to request SIR DTCs displayed.

Does the scan tool indicate that DTC B0022, B0024, B0026, B0042, B0043, or B0044 are current?

Go to Step 6

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect and remove both the J 38715-A and adapter.
  3. Connect the steering wheel module coil in-line connector.
  4. Remove the steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
  5. Use the J 38715-120 adapter to connect the J 38715-A to the upper steering wheel module coil connector on top of the steering column. Use STEERING COLUMN and PASSENGER INFLATOR connectors.
  6. Turn ON the ignition, with the engine OFF.
  7. Use the scan tool to request SIR DTCs displayed.

Does the scan tool indicate that DTC B0022, B0024, B0026, B0042, B0043, or B0044 are current?

Go to Step 9

Go to Step 8

6

  1. Turn OFF the ignition.
  2. Disconnect and remove both the J 38715-A and adapter.
  3. Disconnect the inflatable restraint sensing and diagnostic module (SDM) connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  4. Inspect the SDM connector for damage or corrosion that may cause a malfunction in the steering wheel module stage 1 or stage 2 high and/or low circuits. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

  1. If DTC B0022 or B0042 is present, test the steering wheel module for a short between the high and low circuits in stage 1 or stage 2.
  2. If DTC B0024 or B0043 is present, test the steering wheel module high and low circuits for a short to ground and for a short to voltage in stage 1 or stage 2.
  3. If DTC B0026 or B0044 is present, test the steering wheel module high and low circuits for an open and for high resistance in stage 1 or stage 2.
  4. If any of the above conditions exist, refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 10

8

  1. Turn OFF the ignition.
  2. Replace the steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .

Did you complete the replacement?

Go to Step 11

--

9

  1. Turn OFF the ignition.
  2. Replace the steering wheel module coil. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .

Did you complete the replacement?

Go to Step 11

--

10

  1. Turn OFF the ignition.
  2. Replace the sensing and diagnostic module (SDM). Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

--

11

  1. Connect all SIR components.
  2. Turn ON the ignition, with the engine OFF.
  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