Camshaft Position (CMP) Sensor (Q45)

CMP sensor monitors engine speed and No. 1 cylinder TDC position. This sensors primary function is to provide the PCM with No. 1 cylinder TDC signal during start up. PCM uses this signal to determine the proper firing of each ignition coil. CMP sensor has a disc containing 2 sets of slits. On the outer ring, slits are one degree apart, while the inner ring of slits are 45 degrees apart. An LED light and photodiode (for each set of slits) creates a pulsating voltage when LED light is broken. The outer ring is for engine speed and the inner ring determines No. 1 cylinder TDC position for injector and ignition timing.