Crankshaft Position Sensor: Description and Operation

Crank Shaft Sensor Circuit:

Camshaft Position (TDC) Sensor:

CAMSHAFT POSITION SENSOR

PURPOSE
The Crankshaft Position and the Camshaft (TDC) Sensors, create square wave signals used by the ECU as reference for ignition and fuel injection timing.

LOCATION
Located within the distributor housing.

CONSTRUCTION
Both sensors are incorporated into one unit consisting of a semiconductor wafer element and a permanent magnet. A rotating shutter, called the trigger wheel, acts as a switching device to produce the Hall signal.

Hall Generator:

Standard Wave Pattern:

OPERATION
The trigger wheel rotates within a space in the hall sensors. As the distributor shaft rotates, the trigger wheel shutter passes through the opening. This temporarily blocks the magnetic field and causes the voltage signal to drop. As the shutter passes the hall sensor and no longer blocks the magnetic field, the voltage rises.