Camshaft Position Sensor: Description and Operation

Fig. 1 Camshaft Position Sensor Location:

The camshaft position sensor (CMP) is mounted in the front of the timing case cover. It is a hall effect device.

Fig. 2 Camshaft Position Sensor:

The CMP sensor contains a hall effect device called a sync signal generator to generate a fuel sync signal. The camshaft position sensor helps provide cylinder identification to the Powertrain Control Module (PCM). The sensor generates pulses as groups of slots on the camshaft sprocket pass underneath it. The PCM keeps track of crankshaft rotation and identifies each cylinder by the pulses generated by the slots on the camshaft sprocket. Crankshaft pulses follow each group of camshaft pulses.

When metal aligns with the sensor, voltage goes low (less than 0.3 volts). When a slot aligns with the sensor, voltage spikes high (5.0 volts). As a group of slots pass under the sensor, the voltage switches from low (metal) to high (slot) then back to low. The number of slots determine the amount of pulses. If available, an oscilloscope can display the square wave patterns of each timing event.