Camshaft Position Sensor: Description and Operation

Camshaft Sensor:

The camshaft sensor is located on the timing cover behind the water pump, near the camshaft sprocket. The camshaft sensor is activated as the interrupter rotates with it's cam driven shaft and passes between the magnet and Hall-Effect switch. When the Hall-Effect switch is activated it grounds the signal to the ignition module, pulling the Crank Signal lines applied voltage low. This is interpreted by the ECM as a Cam Signal. This Cam Signal can also be seen as a square wave because the voltage is either high or low. The Cam Signal is created as piston #1 and piston #4 reach 25° after top dead center. It is then used by the ignition module to begin the ignition coil firing sequence starting with the #3/6 coil. The firing sequence begins with this coil because piston #6 is now in the correct position on it's compression stroke for the spark plugs to be fired. This cam signal is also used by the ECM to time the Sequential Fuel Injection (SFI) operation.