GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Corvette 🢒 Restraints 🢒 SIR 🢒 DTC B0026

Circuit Description

The steering wheel module deployment loop consists of an inflatable restraint steering wheel module, an inflatable restraint steering wheel module coil, the steering wheel module - high control and steering wheel module - low control circuits. A shorting bar is used in the inflatable restraint steering wheel module and the inflatable restraint steering wheel module coil connectors which will short together the steering wheel module - high control and steering wheel module - low control circuits when the connector is disconnected, this will help to prevent unwanted deployment of the inflator module during servicing. During a frontal crash of sufficient force the SDM will allow current to flow through the deployment loop in order to deploy the inflatable restraint 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.

Conditions for Running the DTC

Ignition 1 Voltage is within the normal operating voltage range.

Conditions for Setting the DTC

The DTC will set if one of the following conditions occurs:

    • The steering wheel module deployment loop resistance is 6 ohms or more for 300 milliseconds.
    • steering wheel module - high control input is less than 2 volts and the steering wheel module deployment loop resistance is 4.8 ohms or more for 500 milliseconds.

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.
    • A history DTC will clear once 255 malfunction free ignition cycles have occurred.

Diagnostic Aids

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.

The following are possible causes of the malfunction:

    • An open or high resistance in the steering wheel module - high control or the steering wheel module - low control circuits.
    • A malfunctioning inflatable restraint steering wheel module.
    • A malfunctioning inflatable restraint steering wheel module coil.
    • An internal SDM malfunction.

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Tests to see if the malfunction is intermittent.

    2.

  2. Tests to see if the malfunction is caused by either the inflatable restraint steering wheel module or steering wheel module coil.

    3.

  3. Determines whether the malfunction is caused by the steering wheel module or the steering wheel module coil.

    4.

  4. Tests for an open or high resistance in the steering wheel module - high control or steering wheel module - low control circuits.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

1

Did you perform A Diagnostic System Check - SIR?

Go to Step 2

Go to Diagnostic System Check - SIR

2
  1. Turn OFF the ignition.
  2. Disconnect inflatable restraint steering wheel module coil connector.
  3. Inspect both the component and harness sides of the connector for the following conditions:
    4. • Corrosion
    • Damaged terminals
    • Poor connects/terminal tension

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

Does the connector exhibit any signs of damage or corrosion?

Go to Step 3

Go to Step 4

3
  1. If the component side of the steering wheel module coil connector is damaged, the steering wheel module coil must be replaced. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .
  2. If the harness side of the steering wheel module coil connector is damaged, replace the harness side of the connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 12

--

4

  1. Reconnect the steering wheel module coil connector.
  2. Verify that the connector position assurance (CPA) is properly installed.
  3. Install a scan tool.
  4. Turn ON the ignition, with the engine OFF.
  5. With the scan tool, request the SIR DTC display.

Does the scan tool indicate that DTC B0026 is current?

Go to Step 5

Go to Diagnostic Aids

5

  1. Turn OFF the ignition.
  2. Disconnect the lower steering wheel module coil connector.
  3. Use the J 38715-90 adapter to connect the J 38715-A SIR Driver/Passenger Load Tool to the wiring harness side of the steering wheel module coil connector.
  4. Turn ON the ignition, with the engine OFF.
  5. With the scan tool, request the SIR DTC display.

Does the scan tool indicate that DTC B0026 is current?

Go to Step 9

Go to Step 6

6

  1. Turn OFF the ignition.
  2. Disconnect the J 38715-A.
  3. Connect the lower steering wheel module coil connector.
  4. Remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
  5. Use the J 38715-30A adapter to connect the J 38715-A SIR Driver /Passenger Load Tool to the upper steering wheel module coil connector.
  6. Turn ON the ignition, with the engine OFF.
  7. With the scan tool, request the SIR DTC display.

Does the scan tool indicate that DTC B0026 is current?

Go to Step 7

Go to Step 8

7
  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 12

--

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 12

--

9
  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Disconnect the SDM connector.
  4. Inspect the SDM connector for the following conditions:
    5. • Corrosion
    • Damaged terminals
    • Poor connects/terminal tension

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 12

Go to Step 10

10

Test the steering wheel module - high control and the steering wheel module - low control circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 11

11
  1. Turn OFF the ignition.
  2. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Did you complete the replacement?

Go to Step 12

--

12
  1. Reconnect all SIR 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