Camshaft Position (CMP) Sensor


Description & Operation

The camshaft position sensor monitors the engine speed and position of the pistons. It sends signals to the ECM to control fuel injection, ignition timing and other functions. The camshaft position sensor has a rotor plate and a wave-forming circuit. The rotor plate has 360 slits for one degree signal and eight slits for 90 degree signal. Light Emitting Diodes (LED) and photo diodes are built into the wave-forming circuit. When the rotor plate passes between the LED and the photo diode, the slits in the rotor plate continually cut the transmitted light to the photo diode from the LED. This generates rough-shaped pulses converted into on-off pulses by the wave forming circuit sent to the ECM. For some models, the distributor is not repairable and must be replaced as an assembly except the cap and rotor head.

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Fig. The camshaft position sensor