GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Monte Carlo 🢒 Restraints 🢒 SIR 🢒 DTC B0042

Circuit Description

The inflatable restraint steering wheel module deployment loop consists of a dual stage inflatable restraint steering wheel module, the inflatable restraint steering wheel module coil, and the steering wheel module stage 2 high and steering wheel module stage 2 low circuits. A shorting bar is used in the inflatable restraint steering wheel module coil connector which will short the steering wheel module stage 2 high and steering wheel module stage 2 low circuits when the connector is disconnected. This will prevent unwanted deployment of the steering wheel module during servicing. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs continuous diagnostic tests on the deployment loop to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, the SDM will store a diagnostic trouble code (DTC).

Conditions for Running the DTC

Ignition 1 voltage is within the normal operating voltage range.

Conditions for Setting the DTC

Steering wheel module stage 2 deployment loop resistance is less than 1.3 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 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 misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • A short between the steering wheel module stage 2 high and steering wheel module stage 2 low circuits
    • The steering wheel module upper coil connectors
    • The steering wheel module coil connector
    • The SDM connector
    • 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. Test to see if the malfunction is caused by the steering wheel module or the steering wheel module coil.

    3.

  3. Tests to see if there is a short between the steering wheel module stage 2 high and steering wheel module stage 2 low circuits.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

1

Did you perform the Diagnostic System Check - SIR?

Go to Step 2

Go to Diagnostic System Check - SIR

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

Does the steering wheel module coil 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.
  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 a scan tool, observe the SIR DTC display.

Does the scan tool indicate that DTC B0042 is current?

Go to Step 5

Go to Diagnostic Aids

5
  1. Turn OFF the ignition.
  2. Disconnect the steering wheel module coil connector.

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

  3. Use the J 38715-80 adaptor to connect the J 38715-A SIR Driver/Passenger Load Tool PASSENGER INFLATOR and BASE OF COLUMN connectors to the harness side of the steering wheel module coil connector.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the SIR DTC display.

Does the scan tool indicate that DTC B0042 is current?

Go to Step 9

Go to Step 6

6

  1. Turn OFF the ignition.
  2. Disconnect the J 38715-A .
  3. Reconnect the steering wheel module coil connector.
  4. Remove the steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .

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

  5. Use the J 38715-120 adaptor to connect the J 38715-A SIR Driver/Passenger Load Tool STEERING COLUMN and PASSENGER INFLATOR connectors to the steering wheel module upper coil connectors on top of the steering column.
  6. Turn ON the ignition, with the engine OFF.
  7. With a scan tool, observe the SIR DTC display.

Does the scan tool indicate that DTC B0042 is current?

Go to Step 8

Go to Step 7

7
  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

--

8
  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

--

9
  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Disconnect the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  4. Inspect the SDM connector for damage or corrosion that may cause the malfunction. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the problem?

Go to Step 12

Go to Step 10

10

Test the steering wheel stage 2 high and steering wheel stage 2 low circuits for a short between the two circuits. 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

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. Use the scan tool in order to clear the DTCs.
  3. 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