The CKPS(Crank Position sensor) is a magnetic transducer mounted on the engine block adjacent to a pulse wheel located on the crankshaft. By monitoring the crankshaft mounted pulse wheel, the CKPS is the primary sensor for ignition information to the ECM. By monitoring the pulse wheel, the CKPS signal indicates crankshaft position and speed information to the ECM. By monitoring the missing tooth, the CKPS is able to identify piston travel in order to synchronize the ignition system and provide a way of tracking the angular position of the crankshaft relative to a fixed reference for the CKPS configuration. The ECM also uses the CKPS signal to determine if a misfire has occurred by measuring rapid decelerations between teeth.

The CMPS(Camshaft Position sensor) detects the position of the camshaft. The CMPS identifies when piston number 1 is on its compression stroke. A signal is then sent to the ECM and used for synchronizing the sequential firing of the fuel injectors. Coil on plug ignition applications use the CMPS signal to select the correct ignition coil to fire. Inline engines with 2 camshafts and with CVVT(Continuously Variable Valve Timing) are equipped with 2 CMPSs. The second sensor identifies the exhaust camshaft position.