Intermittent Problem Diagnosis

Intermittent fault testing requires duplicating circuit or component failure to identify problem. These procedures may lead to computer setting a fault code (on some systems) which may help in diagnosis.

If problem vehicle does not produce fault codes, monitor voltage or resistance with a DVOM while attempting to reproduce conditions causing intermittent fault. A status change on DVOM indicates a fault has been located.

Use a DVOM to pinpoint faults. When monitoring voltage, make sure that ignition is on or engine is running. Turn ignition off or disconnect negative battery cable when monitoring circuit resistance. Status changes on DVOM during test procedures indicate area of fault.