When the ignition switch is turned to the ON position, the inflatable restraint sensing and diagnostic and seat belt pretensioner module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM monitors the six deployment loops to detect leakage currents to ground in the frontal air bag deployment loops, the side air bag deployment loops and the seat belt pretensioner deployment loops. Then, the SDM proceeds with the RESISTANCE MEASUREMENT test to measure the deployment loop resistances to ensure they are within their respective normal resistance ranges. Upon passing these tests, the energy reserve is charged and the firing transistors are tested. The SDM then goes into CONTINUOUS MONITORING mode. The SDM service wait time is 1 minute. Refer to ENABLE/DISABLE procedures.

DTC 71 will set when the following conditions are met:

The driver side impact sensor (SIS) loop consists of the following components:

Current and History DTC codes must be cleared using a scan tool Clear DTC Information command. If the circuit fault has been successfully repaired and the conditions which caused the Current DTC 71 to set are no longer existing, History DTC 71 will set. History DTC 71 may be cleared using the scan tool.

An inflatable restraint driver side impact sensor (SIS) circuit short to ground, short to B+, open, or high resistance can cause an intermittent condition. Inspect CKT B41, CKT B42 and CKT XB42 carefully for cutting and/or chafing. A careful inspection of the circuits and components indicated on the DTC 71 table is essential to make sure that the replacement SDM will not be damaged.

The following numbers refer to the step numbers in the diagnostic table:

2. This step checks to see if either DTC 73 or DTC 74 is also present.

4. This step checks the communication status of the driver side impact sensor (SIS).