B1125

Circuit Description
When you first turn the ignition switch to the ON position, the Inflatable Restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. Upon passing these tests Ignition 1, 23VLR and the deployment loop voltages are measured to make sure they are within their respective normal voltage ranges. The SDM monitors the voltages at Driver Frontal Low terminal 9 and Passenger Frontal Low terminal 8 to detect shorts to voltage in the inflator module circuits.

Conditions for Setting the DTC
The voltage at Driver Frontal Low terminal 9 or Passenger Frontal Low terminal 8 is more than 4.0 volts for 500 milliseconds. The following tests check for this DTC. These tests occur when Ignition 1 is within the normal operating voltage range.
^ Power-On-When 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 cluster (IPC) to turn ON the AIR BAG warning lamp.

Conditions for Clearing the MIL/DTC
^ The voltage measured at Driver Frontal Low and Passenger Frontal Low is below 4.0 volts for 500 milliseconds.
^ The ignition switch is turned OFF.
^ DTC B1171 will remain Current.

Diagnostic Aids
A short to voltage in the Inflatable Restraint Steering Wheel Module circuit or the passenger inflator module circuit can cause an intermittent condition. Moving wires while monitoring Driver Frontal Senselo and Passenger Frontal Senselo may help to locate the fault. Inspect circuit 347, circuit 348, circuit 1403, and circuit 1404 carefully for cutting or chafing. The diagnostic table directs the technician to note the entry value of Driver Frontal Senselo and Passenger Frontal Senselo. Noting the value of Driver Frontal Senselo and Passenger Frontal Senselo during diagnosis can be helpful in determining if an intermittent condition exists.

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 Diagrams. 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 Driver Frontal Low voltage measured by the Inflatable Restraint Sensing and Diagnostic Module (SDM) and if the malfunction is currently occurring.
3. This test isolates the malfunction to one side of the Inflatable Restraint Steering Wheel Module Coil yellow 2-way connector.
4. This test determines whether the malfunction is due to the Inflatable Restraint Steering Wheel Module or the module coil.
7. This test determines whether the malfunction is in circuit 347.
9. his test determines whether the malfunction is in circuit 348.
11. This test isolates the malfunction to one side of the Inflatable Restraint Instrument Panel (IP) module, yellow 2-way connector.
13. This test determines whether the malfunction is in circuit 1404.
15. This test determines whether the malfunction is in circuit 1403.

Notice: When DTC B1125 or DTC B1145 has been set it is necessary to replace the Inflatable Restraint Sensing and Diagnostic Module (SDM). Setting DTC B1125 or DTC B1145 will also cause DTC B1171 to set. When a scan tool clear codes command is issued and the malfunction is no longer present, DTC B1171 will remain current. Make sure that the short to voltage condition is repaired prior to installing a replacement SDM to avoid damaging the SDM.

Important: To avoid damaging a replacement SDM, the short to voltage must be repaired prior to installation.