Camshaft Position Sensor: Description and Operation

CAMSHAFT POSITION (CMP) SENSOR

The camshaft position (CMP) sensor is a Hall-Effect type sensor. The CMP signal is a digital ON/OFF pulse, which outputs once per revolution of the camshaft. The CMP sensor does not directly affect the operation of the ignition system. The CMP sensor information is used by the engine control module (ECM) to determine the position of the valve train relative to the crankshaft position. By monitoring the CMP and crankshaft position (CKP) signals, the ECM can accurately trigger the fuel injectors. This allows the ECM to calculate true sequential fuel injection mode of operation. If the CMP signal is lost while the engine is running, the fuel injection system will shift to a calculated sequential fuel injection mode based on the last fuel injection pulse, and the engine will continue to run. The CMP sensor consists of an ignition 1 voltage circuit, a ground circuit, and a signal circuit.