Engine speed is an important input to the Engine Management System (EMS). Crankshaft speed and position are the basis for many calculations made by the computer. Crankshaft position values are transmitted to the computer by pickup coils also known as Permanent Magnet (P/M) generators, Hall Effect sensors or optical sensors. The Crankshaft Position Sensor (CKP) also known as an engine speed sensor is typically located in close proximity to the crankshaft.
In addition, the EMS uses the CKP sensor in conjunction with the camshaft position sensor to calculate and perform misfire diagnostics.