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B0042




DTC B0022, B0024, B0026, B0042, B0043, or B0044

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptors
DTC B0022
- Driver Frontal Deployment Loop (Stage 1) Resistance Low

DTC B0024
- Driver Frontal Deployment Loop (Stage 1) Voltage Out of Range

DTC B0026
- Driver Frontal Deployment Loop (Stage 1) Open

DTC B0042
- Driver Frontal Deployment Loop (Stage 2) Resistance Low

DTC B0043
- Driver Frontal Deployment Loop (Stage 2) Voltage Out of Range

DTC B0044
- Driver Frontal Deployment Loop (Stage 2) Open

Diagnostic Fault Information





Circuit/System Description

During a frontal crash of sufficient force the inflatable restraint sensing and diagnostic module (SDM) will allow current to flow through the deployment loop in order to 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. There are 2 shorting bars used within the steering wheel module coil connector which will short together both steering wheel module stage 1 high circuit and steering wheel module stage 1 low circuit and both steering wheel module stage 2 high circuit and steering wheel module stage 2 low circuit when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B0022 stage 1 or B0042 stage 2

The steering wheel module deployment loop resistance is less than 1.3 ohms for 500 milliseconds.

B0024 stage 1 or B0043 stage 2
* The steering wheel module stage 1 or stage 2 high circuit is less than 2.4 volts and the steering wheel module stage 1 or stage 2 deployment loop is greater than 6 ohms for 500 milliseconds.
* The steering wheel module stage 1 or stage 2 deployment loop resistance is greater than 4.8 ohms for 500 milliseconds.

B0026 stage 1 or B0044 stage 2
* The steering wheel module stage 1 or stage 2 high and/or low circuits is short to ground or short to voltage for 500 milliseconds.
* The steering wheel module stage 1 or stage 2 high circuit is less than 2.4 volts and steering wheel module stage 1 or stage 2 deployment loop resistance is less than 6 ohms for 500 milliseconds.

Action Taken When the DTC Sets

* The SDM requests the instrument panel cluster (IPC) the AIR BAG indicator.
* The SDM will store a DTC, however if an event occurs the system will still attempt deployments.

Conditions for Clearing the DTC

* The condition for setting the DTC no longer exists.
* A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Reference Information
Schematic Reference

SIR Schematics ([1][2]Air Bag Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

SIR System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
* SIR/SRS Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information
Special Tools

J 38715-A Driver and Passenger SIR Load Tool

Circuit/System Testing

Important: When removing connectors inspect for damage or corrosion. Damage or corrosion to the following requires repair or replacement of the affected component/connector:


* Pretensioner

* Air bag module

* SDM module

* Air bag wiring harness connector

* SDM wiring harness connector


The connector and connector position assurance (CPA) may seat independent of each other. Both the connector and CPA should seat with an audible and/or tactile click. The CPA isolates the shorting-bars within the connector allowing the deployment circuit to operate properly.


1. Verify that the steering wheel inflator restraint module connector and CPA are engaged.

• If the above condition is not found, make the appropriate repair.

2. Ignition OFF, disconnect the harness connector at the steering wheel inflator module.
3. With the appropriate load tool adaptor, connect J 38715-A in place of the steering wheel inflator module.
4. Ignition ON, with a scan tool, verify the appropriate DTC is set as current.

• If the DTC is not set or is set as history, cycle ignition OFF, disconnect the adapter and J 38715-A , reconnect the harness connector at the steering wheel inflator module, and cycle the ignition ON. If the DTC resets after reconnecting the module, replace the steering wheel inflator module.

5. Ignition OFF, disconnect J 38715-A and the adaptor.
6. Disconnect the steering wheel module coil in-line connector.
7. With the applicable adaptor, connect J 38715-A .
8. Ignition ON, with a scan tool, verify DTC is set as current.

• If DTC is not set or is set as history, replace the steering wheel module coil.

9. Ignition OFF, disconnect J 38715-A and the applicable adaptor.
10. Ignition ON, test for less than 1 volt between the applicable HI circuit and ground.

• If not the specified range, test the circuit for a short to voltage.

11. Test for less than 1 volt between the applicable LOW circuit and ground.

• If not the specified range, test the circuit for a short to voltage.

12. Ignition OFF, test for infinite resistance between the applicable HI circuit and ground.

• If not the specified range, test the circuit for a short to ground.

13. Test for infinite resistance between the applicable LOW circuit and ground.

• If not the specified range, test the circuit for a short to ground.

14. Disconnect the harness connector at the SDM.
15. Test for less then 1 ohm between the SDM connector and the air bag module connector HI circuit.

• If not the specified range, test the circuit for an open/high resistance.

16. Test for less then 1 ohm between the SDM connector and the air bag module connector LOW circuit.

• If not the specified range, test the circuit for an open/high resistance.

17. If all circuits test normal, replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Inflatable Restraint Steering Wheel Module Replacement (Service and Repair)
* Inflatable Restraint Steering Wheel Module Coil Centering (Procedures)
* Control Module References (Programming and Relearning) for SDM replacement, setup, and programming

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