Camshaft Position Sensor: Description and Operation

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

Camshaft Position Sensor:

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.

When the rotor passes between the photo diodes and LED's the slits in the rotor plate continually cut the light being transmitted to the photo diode from the LED. This generates rough shaped pulses which are converted into ON/OFF signals by the wave forming circuit, which are sent to the ECM.