• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category

For symptom byte information refer to Symptom Byte List.

Under certain vehicle events involving an impact or predicted roll over event of sufficient force, the Inflatable Restraint Sensing and Diagnostic Module will apply current through the appropriate deployment loops, commanding deployment of the appropriate airbag(s) and/or Pretensioner(s). The SDM performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage.

Ignition voltage is between 9–16 V.

The steering wheel air bag deployment loop is shorted to voltage for 2 s

The steering wheel air bag deployment loop is shorted to ground for 2 s

The steering wheel air bag deployment loop is open for 2 s

The steering wheel air bag deployment loop resistance is greater than 4.4 Ω for 2 s

The steering wheel air bag deployment loop resistance is less than 1.7 Ω for 2 s

• The inflatable restraint sensing and diagnostic module requests the instrument cluster to illuminate the AIR BAG indicator.
• The inflatable restraint sensing and diagnostic module will store a DTC, however if an event occurs the system will still attempt deployment.

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

Refer to SIR Service Precautions.

Refer to SIR Disabling and Enabling.

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 a reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections.

A worn steering wheel air bag coil can cause a repeated history DTC to set. To verify this condition, Refer to Circuit/System Testing.

An incorrectly installed connector position assurance (CPA) or incorrectly seated connector can cause a shorting bar (if equipped) to short both control circuits together. Check the connectors and CPAs if a DTC with symptom byte 02 or 0E is set, to ensure the shorting bars are not causing the circuits to be shorted together.

Check for an incorrectly seated connector as this can cause an open/high resistance condition if a DTC with symptom byte 04 or 0D is set.

SIR Schematics

Master Electrical Component List

Supplemental Inflatable Restraint System Description and Operation

• Circuit Testing
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Connector Repairs

Control Module References for scan tool information

EL-38125-580 Terminal Release Tool Kit

Refer to SIR Service Precautions.

1. Verify the appropriate scan tool Deployment Loop Resistance parameters stay consistently between 2.1–4.0 Ω without any spikes or dropouts while turning the steering wheel 360 degrees in one direction then back 360 degrees in the other direction.
• If less than 2.1 Ω or greater than 4.0 Ω

  Refer to Circuit/System Testing.

• If between 2.1–4.0 Ω without any spikes or dropouts
2. The condition is not currently present and may be an intermittent fault.

1. Ignition OFF.
2. Verify the SIR system is disabled.
3. Disconnect the scan tool and disconnect the appropriate harness connector listed below at the F107 Driver Steering Wheel Air Bag.
• DTC B0012 connector X1
• DTC B0013 connector X2
4. Test for greater than 25 Ω between the control circuit terminal 1 and the control circuit terminal 2.
• If 25 Ω or less
1. Verify the SIR system is disabled.
2. Disconnect the X1 harness connector at the K36 Inflatable Restraint Sensing and Diagnostic Module.

Note: Some connectors may be equipped with shorting bars as a safety component to prevent accidental deployment. When testing on a connector with shorting bars, the shorting bars must be disabled to ensure accurate test results. Insert an appropriate pick from EL-38125-580 and depress the shorting bars above the appropriate terminals. This will lift the shorting bar from the terminal and allow accurate test results. Take care not to damage the connector, shorting bar, or terminal when depressing the shorting bar.

3. Test for infinite resistance between the two control circuits.
• If less than infinite resistance, repair the short between the two circuits.
• If infinite resistance, replace the K36 Inflatable Restraint Sensing and Diagnostic Module.
• If greater than 25 Ω
5. Ignition ON.
6. Test for less than 11 V between each control circuit terminal listed below and ground:
• Control circuit terminal 1
• Control circuit terminal 2
• If 11 V or greater
1. Ignition OFF.
2. Verify the SIR system is disabled.
3. Disconnect the X1 harness connector at the K36 Inflatable Restraint Sensing and Diagnostic Module.
4. Ignition ON.
5. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K36 Inflatable Restraint Sensing and Diagnostic Module.
• If less than 11 V
7. Ignition OFF.
8. Test for greater than 25 Ω between each control circuit terminal listed below and ground:
• Control circuit terminal 1
• Control circuit terminal 2
• If 25 Ω or less
1. Verify the SIR system is disabled.
2. Disconnect the X1 harness connector at the K36 Inflatable Restraint Sensing and Diagnostic Module.

Note: Some connectors may be equipped with shorting bars as a safety component to prevent accidental deployment. When testing on a connector with shorting bars, the shorting bars must be disabled to ensure accurate test results. Insert an appropriate tool from EL-38125-580 and depress the shorting bars above the appropriate terminals. This will lift the shorting bar from the terminal and allow accurate test results. Take care not to damage the connector, shorting bar, or terminal when depressing the shorting bar.

3. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K36 Inflatable Restraint Sensing and Diagnostic Module.
• If greater than 25 Ω
9. Verify the SIR system is disabled.
10. Install a 3 A fused jumper wire between the control circuit terminal 1 and the control circuit terminal 2, ignition ON.
11. Verify the SIR system is enabled.
12. Verify the appropriate scan tool Deployment Loop Resistance parameter is consistently less than 2 Ω while turning the steering wheel 360 degrees in one direction then back 360 degrees in the other direction.
• If the reading is erratic while turning the steering wheel

  Replace the X85 Steering Wheel Air Bag Coil.

• If 2 Ω or greater
1. Ignition OFF.
2. Verify the SIR system is disabled.
3. Disconnect the X1 harness connector at the K36 Inflatable Restraint Sensing and Diagnostic Module.
4. Test for less than 2 Ω in the X85 Steering Wheel Airbag Coil and each control circuit end to end.
• If 2 Ω or greater, replace the X85 Steering Wheel Air Bag Coil or repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K36 Inflatable Restraint Sensing and Diagnostic Module.
• If less than 2 Ω
13. Ignition OFF.
14. Verify the SIR system is disabled.
15. Connect the harness connector at the F107 Steering Wheel Air Bag, press in the CPA (if equipped) until an audible and/or tactile click is heard.
16. Ignition ON, clear DTCs. Operate the vehicle within the Conditions for Running the DTC.
17. Verify DTC B0012 or B0013 is not set.
• If DTC B0012 or B0013 is set

  Test or replace the F107 Steering Wheel Air Bag.

• If DTC B0012 or B0013 is not set
18. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

• Steering Wheel Airbag Coil Replacement
• Steering Wheel Airbag Replacement
• SIR/SRS Wiring Repairs
• Control Module References for inflatable restraint sensing and diagnostic module replacement, programming and setup