B1026

Circuit Description
When you first turn the ignition switch to the RUN position, the Inflatable Restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within the SDM. Next the SDM measures IGNITION 1 voltage to ensure that the IGNITION 1 is within the IGNITION 1's respective normal voltage range. Then the SDM proceeds with the DEPLOYMENT LOOP CONTINUITY test. During the DEPLOYMENT LOOP CONTINUITY test, the SDM measures the voltage difference between DRIVER SIDE HIGH and DRIVER SIDE LOW.

Conditions for Setting the DTC
^ The voltage difference between DRIVER SIDE HIGH terminal 2 and DRIVER SIDE LOW terminal 3 is more than or equal to 400 millivolts.
^ The malfunction must be 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 lamp.

Conditions for Clearing the DTC
^ Current DTC
The voltage difference between DRIVER SIDE HIGH terminal 2 and DRIVER SIDE LOW terminal 3 is less than 400 millivolts for 500 milliseconds.
^ History DTC
- You issue a scan tool CLEAR CODES command
- After 250 malfunction free ignition cycles have occurred

Diagnostic Aids
The following 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 could also set this DTC. To test for a bad Inflatable Restraint Steering Wheel Module Coil, clear the DTCs, then turn the steering wheel back and forth with the ignition switch in the RUN position. If the AIR BAG warning lamp comes ON and DTC B1026 has set again, the problem is likely the Inflatable Restraint Steering Wheel Module Coil is malfunctioning.
When measurements are requested in this table, use the J 39200 DMM with the correct terminal adapter from the J 35616-A Connector Test Adapter Kit. When an inspection for proper connection is requested, refer to Testing for Electrical Intermittents. When a wire, connector or terminal repair is requested, use the J 38125-B Terminal Repair Kit and refer to Wiring Repairs.

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 inspects 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 inspects for proper contact or corrosion of the SDM connector.
18. This test determines whether the malfunction is in circuit 347.
21. This test determines whether the malfunction is in circuit 348.