Camshaft Position Sensor: Description and Operation

The CMP sensor located in the distributor consists of the signal generator (hall element and magnet) and signal rotor. As the signal rotor turns, it causes the magnetic flux from the magnet to be applied to the hall element intermittently. The hall element generates the voltage in proportion with the magnetic flux as shown in figure. This voltage is wave-shaped into the pulse signal (sensor signal) by the comparator and sent to ECM.
Receiving this pulse signal (4 pulses/revolution), ECM detects the engine speed and the piston position of each cylinder and uses that information as one of signals to control the fuel injector and ignition timing.