Camshaft Position Sensor: Description and Operation

CAMSHAFT POSITION (CMP) SENSOR

The camshaft position (CMP) sensor is triggered by a notched reluctor wheel built into the exhaust camshaft sprocket. The CMP sensor provides four signal pulses every camshaft revolution. Each notch, or feature of the reluctor wheel, is of a different size for individual cylinder identification. This means the CMP and CKP signals are pulse width encoded to enable the PCM to constantly monitor their relationship. This relationship is used to determine camshaft actuator position and control its phasing at the correct value. The PCM also uses this signal to identify the compression stroke of each cylinder, and for sequential fuel injection. The CMP sensor is connected to the PCM by a 12-volt circuit, a low reference circuit, and a signal circuit.