While the timing may be set by the PCM, it has to get information on the crankshaft position from somewhere. If the info it is getting is wrong or a crankshaft sensor is faulty, then the ignition timing will be out. While the timing may be set by the PCM, it has to get information on the crankshaft position from somewhere. If the info it is getting is wrong or a crankshaft sensor is faulty, then the ignition timing will be out.

crankshaft sensor tell where is the number 1.and give the rpm. the pcm base the timing according to the load on engine ,the tps. maf and so on. there is tree door behind the harmonic balancer it tell the matching pair of cylinder whose firing crankshaft sensor tell where is the number 1.and give the rpm. the pcm base the timing according to the load on engine ,the tps. maf and so on. there is tree door behind the harmonic balancer it tell the matching pair of cylinder whose firing