Camshaft Position (CMP) Sensor

Courtesy of VOLVO CARS CORPORATION

The function of the camshaft position (CMP) sensor is to detect the flanks of the camshaft rotor. The signal from the sensor is used by the Engine Control Module (ECM) to determine the angle of the camshaft.

Each camshaft is divided into a number of flanks (segments) per camshaft revolution. A pulse wheel on the camshaft consisting of teeth (the teeth are positioned by each flank) is used by the camshaft position sensor (CMP) to detect the flanks and the position of the camshaft.

In the event of misfire or engine knock, the control module is able to determine which cylinder is misfiring or knocking using the camshaft position (CMP) sensor's signal. Also see appropriate information for the Knock sensor and the Engine speed sensor.

Data about the camshaft position is used during camshaft control (CVVT). See: FUNCTION  

The sensor, which is a magnetic resistor with a permanent magnet, is grounded in the control module and supplied with 5 V from the control module. When one of the teeth on the camshaft pulse wheel passes the camshaft position (CMP) sensor, a signal is transmitted to the control module from the camshaft position (CMP) sensor. The signal varies between 0 and 5 V and is high when a tooth is in contact with the camshaft position (CMP) sensor and low when the tooth leaves the camshaft position (CMP) sensor.

There is camshaft position (CMP) sensor for each camshaft.

The camshaft position sensors are located by the camshafts on the engine's right side.

The Engine Control Module (ECM) can diagnose the camshaft position (CMP) sensors.