Crankshaft Position Sensor: Description and Operation

CRANKSHAFT POSITION (CKP) SENSOR

The crankshaft position (CKP) sensor is a 3-wire sensor based on the magneto resistive principle. A magneto resistive sensor uses 2 magnetic pickups between a permanent magnet. As an element such as a reluctor wheel passes the magnets, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The CKP sensor returns a digital ON/OFF pulse 24 times per crankshaft revolution. The pulse width encoding pattern is used to synchronize the coil firing sequence with the crankshaft position. The CKP sensor is used for ignition timing, fuel injector timing, misfire diagnostics, and tachometer display. The powertrain control module (PCM) supplies a 12-volt reference, a low reference, and a medium resolution engine speed signal circuit to the CKP sensor.