B1126

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 module. Next the SDM measures the ignition positive voltage in order to make sure it is within its 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 FRONTAL HIGH and the DRIVER FRONTAL LOW.

Conditions for Setting the DTC
^ The voltage difference between DRIVER FRONTAL HIGH terminal 10 and DRIVER FRONTAL LOW terminal 9 is more than or equal to 426 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 commands the instrument panel cluster (IPC) to turn ON the AIR BAG warning lamp.

Conditions for Clearing the MIL/DTC
^ Current DTC
The voltage difference between DRIVER FRONTAL HIGH terminal 10 and DRIVER FRONTAL LOW terminal 9 is less than 426 millivolts for 500 milliseconds.
^ History DTC
- You issue a scan tool CLEAR CODES command.
- 250 malfunction free ignition cycles occur.

Diagnostic Aids
The following can 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 10 and 9.
^ 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. In order to test for a bad Inflatable Restraint Steering Wheel Module Coil perform the following steps:
1. Clear the DTCs
2. Turn the steering wheel back and forth with the ignition switch in the RUN position.

If the AIR BAG warning tamp comes ON and DTC B1126 has set again, a malfunction in the Inflatable Restraint Steering Wheel Module Coil is likely. The diagnostic table directs the technician to note the scan tool value of the DRIVER VDIF. Comparing the value of the DRIVER VDIF may be helpful in determining if an intermittent condition exists. When measurements are requested in this table, use J 39200 Digital Multi meter 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. Intermittents and Poor Connections

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 Inflatable Restraint Sensing and Diagnostic Module (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.