Tach Pulse (RPM Reference) Signal

Connect scan tester to DLC. Scan low and high resolution reference pulses. Both high and low pulses should be present when engine is cranking or running. If low resolution pulse is not present, engine will not start and PCM will set Code 16 in memory. If high resolution pulse is not present, vehicle will still run; however, PCM will set Code 36 in memory. For circuit and terminal reference, see appropriate schematic in NO START - ENGINE CRANKS OKAY.