Camshaft position sensor is a kind of sensing device, also called synchronous signal sensor. It is a cylinder discrimination and positioning device, which inputs the camshaft position signal to ECU and is the main control signal of ignition control.

The camshaft position sensor (CPS) is used to collect the movement angle signal of the camshaft and input it into the electronic control unit (ECU) to determine the ignition time and fuel injection time. Camshaft position sensor (CPS) is also called cylinder identification sensor (CIS). In order to distinguish it from the crankshaft position sensor (CPS), the camshaft position sensor is generally represented by CIS. The function of camshaft position sensor is to collect the position signal of valve camshaft and input it to ECU, so that ECU can identify the compression top dead center of 1 cylinder, and then carry out sequential fuel injection control, ignition timing control and deflagration control. In addition, the camshaft position signal is also used to identify the first ignition time when the engine is started. Because the camshaft position sensor can identify which cylinder piston is about to reach the top dead center, it is called cylinder identification sensor.