Hall Effect Sensor: Description and Operation
DESCRIPTIONThe camshaft position sensor is located inside the distributor above the magnetic pickup assembly. The camshaft position sensor is a hall effect switch and a magnet separated by an air gap. A 3-wire harness connector plugs into the sensor, connecting it to the Powertrain Control Module (PCM).
OPERATION
A hall effect switch reacts like a solid-state switch, grounding a low-current signal voltage when a magnetic field is present. When the magnetic field is shielded from the switch by a piece of steel placed in the air gap between the magnet and the switch, the signal voltage is not grounded. If the piece of steel (called an interrupter) is repeatedly moved in and out of the air gap, the signal voltage will appear to go "ON-OFF-ON-OFF-ON-OFF." Compared to a conventional mechanical distributor, this "ON-OFF" signal is similar to the signal that a set of breaker points in the distributor would generate as the distributor shaft turned and the points opened and closed.
The camshaft position sensor produces one "ON-OFF" pulse for every one revolution of the camshaft or every two revolutions of the crankshaft. This allows the ignition control module to recognize camshaft position.