Camshaft Position (CMP) Sensor

There are 2 types of CMP sensors used. A 3-pin Hall Effect type sensor or a 2-pin variable reluctance sensor. CMP sensor is used to determine camshaft position and to identify when piston No. 1 is at TDC of compression stroke. CMP sensor signal is used by PCM for synchronizing firing of sequential fuel injectors. Models with Coil On Plug (COP) ignition also use CMP signal to select the proper ignition coil to fire.