Japanese Subaru Camshaft Sensor

Description

How Do Camshaft Position Sensors Work?

The camshaft position sensor, often simply called the cam sensor, is a type of Hall effect sensor. It detects a magnetic field and the strength of the field. Positioned very near to a ring gear on the camshaft, it detects how the camshaft is positioned as it rotates. As the cam rotates, different points on the ring gear cause the sensor’s voltage to vary. This data tells the car’s onboard computer how the camshaft is positioned in the engine so the computer knows cylinder #1’s top dead center (TDC) position. All timing is relative to TDC.

The data from the camshaft position sensor alone isn’t enough to allow the engine to run, however. The onboard computer also requires data from other components like crankshaft position sensor, mass air flow sensor, and several other sensors and systems. Using the camshaft sensor’s data along with other sensors, fuel is injected into cylinders at exactly the right moment and the spark plug fires and ignites the air-fuel mixture.