GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2005 🢒 Century 🢒 Restraints 🢒 SIR 🢒 DTC B0022, B0024, or B0026

Circuit Description

The driver frontal deployment loop consists of the following components:

    • An inflatable restraint steering wheel module
    • The inflatable restraint steering wheel module coil
    • The steering wheel module high circuit
    • The steering wheel module low circuit

A shorting bar is used on the steering wheel module connector as well as the steering wheel module coil connector which will short together the steering wheel module high and steering wheel module low signal circuits when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (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.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC B0022 Driver Frontal Deployment Loop (Single Stage or Stage 1) Resistance Low
    • DTC B0024 Driver Frontal Deployment Loop (Single Stage or Stage 1) Voltage Out of Range
    • DTC B0026 Driver Frontal Deployment Loop (Single Stage or Stage 1) Open

Conditions for Running the DTC

Ignition 1 voltage is within the normal operating voltage range.

Conditions for Setting the DTC
    • DTC B0022 will set when the steering wheel module deployment loop resistance is less than 1.3 ohms for 500 milliseconds.
    • DTC B0024 will set when one of the following conditions occurs:
       - The SDM detects the voltage at steering wheel module high signal is greater than 6 volts for 500 milliseconds.
       - The SDM detects the voltage at steering wheel module high signal is less than 2.4 volts and steering wheel module deployment loop resistance is less than 6 ohms for 500 milliseconds.
    • DTC B0026 will set when one of the following conditions occurs:
       - The SDM detects the steering wheel module deployment loop resistance is greater than 4.8 ohms for 500 milliseconds.
       - The SDM detects the voltage at steering wheel module high signal is less than 2.4 volts and steering wheel module deployment loop resistance is 6 ohms or greater for 500 milliseconds.

Action Taken When the DTC Sets

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

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists.
    • You issue a scan tool CLEAR DTCs command.
    • A history DTC will clear once 255 malfunction free ignition cycles have occurred.

Diagnostic Aids

The following can cause an intermittent condition:

    • A short between the steering wheel module high and steering wheel module low signal circuits
    • A malfunctioning shorting bar on the steering wheel module connector
    • A malfunctioning shorting bar on the steering wheel module coil connector

Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

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

  1. Inspects the steering wheel module coil in-line connector.

    2.

  2. Tests for a malfunctioning steering wheel module.

    3.

  3. If DTC B0022 is present, test for a short between the steering wheel module high and steering wheel module low signal circuits. If DTC B0024 is present, test for a short to ground or voltage in the steering wheel module high and steering wheel module low signal circuits. If DTC B0026 is present, test for an open or high resistance in the steering wheel module high and steering wheel module low signal circuits.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

Connector End View Reference: SIR Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn OFF the ignition.
  2. Disconnect the steering wheel module coil in-line connector located at the base of the steering column. 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 in Wiring Systems.

Does connector exhibits any signs of damage or corrosion?

Go to Step 3

Go to Step 4

3
  1. If the steering wheel module coil connector exhibits any of the above conditions, the coil must be replaced. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .
  2. Replace the harness side of the steering wheel module coil in-line connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the replacement?

Go to Step 11

--

4
  1. Use the J 38715-100 Adapter to connect the J 38715-A SIR Driver/Passenger Load Tool to the harness side of the steering wheel module coil in-line connector.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, request the SIR DTC display.

Does the scan tool indicate that either DTC B0022, B0024, or B0026 is current?

Go to Step 6

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect the J 38715-A and adapter.
  3. Reconnect 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 38715-30A Adapter to connect the J 38715-A to the upper steering wheel module coil connector.
  6. Turn ON the ignition, with the engine OFF.
  7. With a scan tool, request the SIR DTC display.

Does the scan tool indicate that either DTC B0022, B0024, or B0026 is current?

Go to Step 9

Go to Step 10

6
  1. Turn OFF the ignition.
  2. Disconnect the J 38715-A and adapter.
  3. Disconnect the inflatable restraint sensing and diagnostic module (SDM) connector. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
  4. Inspect the SDM connector for corrosion or damage. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

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

Did you find and correct the condition?

Go to Step 11

Go to Step 8

8

Replace the SDM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

--

9

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

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

Did you complete the replacement?

Go to Step 11

--

11
  1. Reconnect all SIR system components.
  2. Verify that all components, connectors and 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