B1026

Circuit Description
When you first turn the ignition switch to the RUN position, the supplemental restraint sensing and diagnostic module SDM) performs tests to diagnose critical malfunctions within itself. Next, the SDM measures IGNITION 1 voltage in order to ensure that the voltage is within the 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 the AIR BAG warning lamp to the ON position.

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 items may cause an intermittent condition:
- A poor connection at the supplemental restraint steering wheel module column connector terminals A and B
- A poor connection at the upper supplemental restraint steering wheel coil connector terminals A and B
- A poor connection at the SDM terminals 2 and 3
- An open in CKT 347
- An open in CKT34B

An intermittent open in the supplemental restraint steering wheel module coil could also set this DTC. In order to test for a bad supplemental 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 supplemental restraint steering wheel module coil is likely to malfunction.
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 an inspection 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.

Steps 1 - 2:

Steps 3 - 7:

Steps 8 - 10:

Steps 11 - 13:

Steps 14 - 19:

Steps 20 - 24:

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 supplemental restraint sensing and diagnostic module.
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 supplemental restraint steering wheel module coil yellow 2-way connector.
11. This test determines whether the malfunction is due to the supplemental restraint steering wheel module or the module coil.
14. This test inspects for proper contact or corrosion of the supplemental restraint sensing and diagnostic module connector.
19. This test determines whether the malfunction is in CKT 347.
21. This test determines whether the malfunction is in CKT 348.