Camshaft Position Sensor: Description and Operation

Camshaft Position Sensor:

PURPOSE
The ECM uses the input from this sensor to determine ignition and fuel injection timing.

Hall Generator:

Standard Wave Pattern:

OPERATION
The trigger wheel mounted on the distributor shaft rotates within a space in the hall sensor.
- As the distributor shaft rotates the trigger wheel shutter passes through the opening, temporarily blocking the magnetic field, causing the voltage signal to drop.
- As the shutter passes the hall sensor and no longer blocks the magnetic field the voltage rises.
- Power to the camshaft position sensor is supplied from the MFI relay and the ground is located in the body.
- A 5V voltage is applied from the engine control module to the camshaft position sensor output terminal and the camshaft position sensor generates a pulse signal as it switches from OPEN to SHORT (power transistor inside the sensor switches ON/OFF) between the output terminal and the ground.

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.