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Home >> Ford >> 2004 >> Taurus SEL, 4D Sedan >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Communication Devices >> MULTIFUNCTION Electronic Control Modules System >> Diagnosis And Testing >> Multifunction Electronic Module >> Principles of Operation
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Principles of Operation

The smart junction box (SJB) constantly monitors its subsystems for concerns. If a concern is found in one of the subsystems, the SJB will record the concern in the form of a diagnostic trouble code (DTC).

The ignition switch position is very important to the SJB functionality. Erratic or unexpected SJB functions can often be traced to problems with these ignition SJB inputs.

The SJB controls a variety of systems: