The Crank Angle Position Sensor is responsible for monitoring the position and rotation speed of the crankshaft in an engine. It provides crucial information to the engine control unit, allowing it to accurately determine the ignition timing and fuel injection timing. This sensor is vital for the proper functioning of the engine, as it ensures that the combustion process occurs at the right time. Without the Crank Angle Position Sensor, the engine may misfire, have poor fuel efficiency, or even fail to start.