Circuit Description

During cranking, Ignition Control Module (ICM) monitors crankshaft position sensor signal. Signal is used to determine correct cylinder pair to spark first. ICM processes signal then sends a fuel control reference pulse to PCM. When PCM receives this pulse, all 6 injectors will be commanded to open for one priming shot of fuel in all cylinders. After priming, injectors remain off for the next 6 fuel control reference pulses from ICM (2 crankshaft revolutions). This allows each cylinder a chance to use fuel from priming shot.

During this waiting period, a cam pulse will have been received by PCM. PCM will now begin to operate injectors sequentially based on true camshaft position. However, if cam signal is not present at start-up, Code P0342 will set and PCM will start sequential fuel delivery in random pattern with a one in 6 chance that fuel delivery is correct.