B1125

NOTICE: When DTC B1125 has been set it is necessary to replace the inflatable restraint Sensing and Diagnostic Module (SDM). Setting DTC B1125 will also cause DTC B1171 to set. When a scan tool clear codes command is issued and the malfunction is still present, DTC B1125 and DTC B1171 will remain current. When a scan tool clear codes command is issued and the malfunction is no longer present, DTC B1125 will clear but DTC B1171 will remain current. Ensure that the short to voltage condition is repaired prior to installing a replacement SDM to avoid damaging the SDM.

When measurements are requested in this table, use J 39200 DVM 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 in Diagram Information in Diagrams. When a wire, connector, or terminal repair is requested, use J 38125-A Terminal Repair Kit and refer to Wiring Repair.

CIRCUIT DESCRIPTION
When you first turn the ignition switch to RUN, the inflatable restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. Upon passing these tests Ignition 1, 23 VLR, and 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 driver deployment loop is not open.
^ The passenger deployment loop is not open.
^ BOTH the passenger deployment loop AND the driver deployment loop are NOT shorted to voltage.
^ 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 DTC B1125 an also B1171.
^ The SDM commands the Instrument Panel Cluster (IPC) to turn ON the AIR BAG warning lamp.

CONDITIONS FOR CLEARING THE 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
An intermittent condition is likely to be caused by a short to voltage in the driver or passenger inflator module circuit. Moving wires while monitoring Drive. Senselo or Passenger Senselo may help locate the fault. Inspect CKTs 347, 348, 1403 and 1404 carefully for cutting or chafing. A careful inspection of the circuits and components indicated on the DTC B1125 Table is essential to make sure that the replacement SDM will not be damaged. The diagnostic table directs the technician to note the entry value of DRIVER and PASSENGER SENSELO. Comparing the value of DRIVER and PASSENGER SENSELO can be helpful in determining if an intermittent condition exists.

DTC TABLE TEST DESCRIPTION
Numbers below refer to step numbers on the diagnostic table.
2. This test determines the voltage at Driver Side Low as measured by the inflatable restraint Sensing and Diagnostic Module (SDM) and if the malfunction is in the driver frontal deployment loop.
3. This test determines the voltage at Passenger Side Low as measured by the SDM and if the malfunction is in the passenger frontal deployment loop.
4. This test isolates the malfunction to one side of the inflatable restraint steering wheel module yellow 2-way connector. This is done by substituting the known good resistance of the load tool and then observing if the malfunction is still present.
5. This test determines whether the malfunction is in the inflatable restraint steering wheel module coil or the inflatable restraint steering wheel module.
8. This test determines whether the malfunction is in CKT 347.
10. This test determines whether the malfunction is in CKT 348.
12. This test isolates the malfunction to one side of the inflatable restraint I/P module, yellow 2-way connector. This is done by substituting the known good resistance of the load tool and then observing if the malfunction is still present.
14. This test determines whether the malfunction is in CKT 1403.
16. This test determines whether the malfunction is in CKT 1404.