Crankshaft Position Sensor: Description and Operation

PURPOSE
The Crankshaft Position Sensor (CMPS) monitors engine speed and piston position and sends signals to the ECCS Control Module (ECM) to control fuel injection, ignition timing and other functions.

Crankshaft Position Sensor:

CPS Rotor Plate:

OPERATION
The crankshaft position sensor has a rotor plate and a wave-forming circuit. The rotor plate has 360 slits for 1° signal and 4 slits for 180° signal. Light Emitting Diodes (L.E.D.) and photo diodes are built in the wave-forming circuit.
When the rotor plate passes between the L.E.D. and the photo diode, the slits in the rotor plate continually cut the light being transmitted to the photo diode from the L.E.D. This generates rough-shaped pulses which are converted into on-off pulses by the wave-forming circuit, which are sent to the ECM.