A crankshaft position sensor is an electronic device used in internal combustion engines, both petrol and diesel, to monitor the position or rotational speed of the crankshaft. The sensor is installed near the main pulley, the flywheel, the camshaft, the transmission bell housing, the engine cylinder block, or the crankshaft itself. The crankshaft position sensor is one of the two most important sensors in modern-day engines, together with the camshaft position sensor. The crankshaft position sensor works by using a magnet or Hall effect device, which is mounted near the crankshaft. As the crankshaft rotates, it passes by the sensor, which detects its position and speed. This information is then sent to the vehicle’s computer which uses it to calculate engine speed and other data. The computer then uses this data to control the fuel injection system, ignition timing, and other engine functions. The crankshaft position sensor can be used in combination with a similar camshaft position sensor (CMP) to monitor the relationship between the pistons and valves in the engine, which is particularly important in engines with variable valve timing. The crankshaft position sensor is an important component of the engine management system, as it helps to ensure that the engine is running efficiently and safely. Without the crankshaft position sensor, the engine would not be able to accurately measure the speed and position of the crankshaft, which could lead to poor performance and even engine damage. Some common symptoms of a bad or failing crankshaft position sensor include check engine light illumination, hard starting and/or stalling, engine runs rough or misfires, poor fuel economy, and sudden drops in RPM.