Diagnostic Aids

A PCM controlled light that is on at all times most likely indicates that a condition is present, requiring vehicle operator's attention. Check for poor connections at PCM or for damaged harness. If harness appears to be okay, disconnect PCM connector and turn ignition on. Using a DVOM, connect DVOM to affected PCM output circuit while moving connectors and harnesses related to PCM output circuit. A change in voltage will indicate location of fault.