Crankshaft Position Sensor: Description and Operation

This system uses a magnetic CKP sensor, mounted remotely from the ICM, which protrudes into the block within approximately 0.050 inches from the crankshaft reluctor. The graphic illustrates a typical sensor in relationship to the crankshaft reluctor. The reluctor is a special wheel which is cast into the crankshaft with 7 slots machined into the wheel, 6 of which are equally spaced (60 degrees apart). A seventh slot is spaced 10 degrees from one of the other slots and serves to generate sync-pules. As the reluctor rotates as part of the crankshaft, the slots change the magnetic field of the sensor, creating an induced voltage pulse. This signal is known as the 7x or low resolution signal because it occurs 7 times per crankshaft resolution. The PCM uses this signal to determine the speed and position of the crankshaft. The 7x reference signal is also used for fuel injector activation and ignition coil sequencing.