Camshaft Position (CMP) Sensor (Q45)

CMP sensor, located in front of left camshaft, monitors engine speed and piston position to control fuel injection, ignition timing and other functions. CMP sensor consists of a rotor plate and a wave-forming circuit. The rotor plate has 360 slits for a one-degree signal and 8 slits for a 90-degree signal. The wave-forming circuit consists of Light Emitting Diodes (LED) and photo diodes. The rotor plate is positioned between the LED and the photo diode. As the rotor plate turns, the slits cut the light to generate rough-shaped pulses. These pulses are converted to on-off signals by the wave-forming circuit and sent to the ECM.