B1026

Circuit Description

When you first turn the ignition switch to the RUN position the Inflatable Restraint Sensing and Diagnostic Module (SDM) performs tests in order to diagnose critical malfunctions within the module. The SDM measures the ignition positive voltage in order to ensure that the voltage is within the respective normal voltage range. The SDM proceeds with the deployment loop continuity test. During the deployment loop continuity test the SDM measures the voltage difference between the DRIVER HIGH and the DRIVER LOW.

Conditions for Setting the DTC

^ The voltage difference between the DRIVER HIGH terminal 2 and DRIVER LOW terminal 3 is more than or equal to 400 millivolts.

^ Ensure that the malfunction is present for at least 500 milliseconds during one of the following tests:

- Deployment loop continuity

If the malfunction is detected in this test, the resistance measurement test will not be performed.

- Continuous monitoring

Action Taken When the DTC Sets

^ The SDM sets a Diagnostic Trouble Code.

^ The SDM turns ON the AIR BAG Warning Indicator.

Conditions for Clearing the MIL/DTC

^ Current DTC

The voltage difference between DRIVER HIGH terminal 2 and DRIVER LOW terminal 3 is less than 400 millivolts for 500 milliseconds.

^ History DTC

- You issue a scan tool CLEAR CODES command.

- Once 250 malfunction free ignition cycles have occurred.

Diagnostic Aids

The following conditions may cause an intermittent condition:

^ A poor connection at the Inflatable Restraint Steering Wheel Module column connector terminals A and B

^ A poor connection at the upper Inflatable Restraint steering wheel coil connector terminals A and B

^ A poor connection at the SDM terminals 2 and 3

^ An open in circuit 347

^ An open in circuit 348

An intermittent open in the Inflatable Restraint Steering Wheel Module Coil may also set this DTC. Clear the DTCs in order to test for a bad Inflatable Restraint Steering Wheel Module Coil, then turn the steering wheel back and forth with the ignition switch in the RUN position. If the AIR BAG warning lamp turns ON and DTC B1026 has set again, the Inflatable Restraint Steering Wheel Module Coil is malfunctioning. When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616-A Connector Test Adapter kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections. When a wire, connector or terminal repair is requested, use J 38125-B Terminal Repair kit and refer to Wiring Repair.

Test Description

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

2. This test determines the deployment loop voltage difference measured by the SDM.

3. This test checks for proper contact or corrosion of the yellow 2-way connector.

10. This test isolates the malfunction to one side of the Inflatable Restraint Steering Wheel Module Coil yellow 2-way connector.

11. This test determines whether the malfunction is due to the Inflatable Restraint Steering Wheel Module or the module coil.

14. This test checks for proper contact or corrosion of the SDM connector.

19. This test determines whether the malfunction is in circuit 347.

21. This test determines whether the malfunction is in circuit 348.