DTC 25

Wiring Diagram:

CIRCUIT DESCRIPTION

When the ignition switch is turned to "ON," the SDM will perform tests to diagnose critical malfunctions within itself. Upon passing these tests "Ignition 1," 23 VLR and deployment loop voltages are measured to ensure they are within their respective normal voltage ranges. The SDM monitors the voltages at "Driver Side Low" terminal "10" and "Passenger Side Low" terminal "3", to detect shorts to B+ in the inflator module circuits.

DTC WILL SET WHEN

"Ignition 1" is in the normal operating voltage range. The voltage measured at both"Driver Side Low" and at "Passenger Side Low" are NOT below a specified value. Once these conditions are met and the voltage at "Driver Side Low" is above 3.5 volts for 500 milliseconds, DTC 25 will set. This test is run during "Turn-ON" tests and every 100 milliseconds during "Continuous Monitoring."

ACTION TAKEN

SDM turns "ON" the "AIR BAG" warning lamp, sets DTC 25 and also DTC 71.

DTC WILL CLEAR WHEN

The malfunction is no longer occurring (has been repaired) and the SDM has been replaced. DTC 25 is a latched code (cannot be cleared).

DTC CHART TEST DESCRIPTION

Numbers below refer to circled numbers on the diagnostic chart.

1. Recording "Driv. Senselo" may help to locate the fault.

2. This test isolates the malfunction to one side of the driver inflator module yellow 2-way connector at the base of the steering column.

3. This test determines whether the malfunction is in CKT G/R.

4. This test determines whether the malfunction is in CKT G.

5. This test determines whether the malfunction is in the coil assembly or the driver inflator module.

DIAGNOSTIC AIDS

The "Driv. Senselo" value displayed by the TECH 1 is updated continuously so that intermittent shorts can be located by moving wires while monitoring "Driv. Senselo." An intermittent condition is likely to be caused by a short to B+ in the driver inflator module circuit. Inspect CKTs G/R, G and the SIR coil assembly pigtails carefully for cutting or chafing. A careful inspection of circuits and components Indicated on the DTC 25 chart including the SIR coil assembly is essential to ensure that the replacement SDM is not damaged.