Crankshaft Position Sensor: Description and Operation

Crankshaft Position (CKP) Sensor:

PURPOSE AND LOCATION

The Crankshaft Position (CKP) Sensor, located in the distributor, monitors engine speed and piston position.


OPERATION

The unit has a rotor plate and a wave forming circuit. The rotor plate has 360 slits for 1° signals and 6 slits for 120° signals. Photo diodes and light emitting diodes (LED's) are used for the wave forming circuit.

As the rotor turns, the slits in the rotor plate cut the light being transmitted to the photo diode from the LED. This generates pulses which are changed into ON/OFF signals by the wave forming circuit. The PCM interprets these signals to calculate engine rpm and cylinder position.