Camshaft Position Sensor: Description and Operation

CAMSHAFT POSITION SENSOR - PCM INPUT

Camshaft Position Sensor (SOHC):

The Camshaft Position Sensor attaches to the rear of the cylinder head. The PCM determines fuel injection synchronization and cylinder identification from inputs provided by the Camshaft Position Sensor and Crankshaft Position Sensor. From the two inputs, the PCM determines crankshaft position.

The PCM sends approximately 8 volts to the hall effect sensor. This voltage is required to operate the hall effect chip and the electronics inside the sensor. A ground for the sensor is provided through the sensor return circuit. The input to the PCM occurs on a 5 volt output reference circuit.

Target Magnet - Typical:

Target Magnet Polarity:

A target magnet attaches to the rear of the camshaft and indexes to the correct position. The target magnet has four different poles arranged in an asymmetrical pattern. As the target magnet rotates, the Camshaft Position Sensor senses the change in polarity. The sensor output switch switches from high (5.0 volts) to low (0.5 volts) as the target magnet rotates. When the north pole of the target magnet passes under the sensor the output switches high. The sensor output switches low when the south pole of the target magnet passes underneath.

The sensor also acts as a thrust plate to control camshaft endplay.