Camshaft Position Sensor: Description and Operation

Camshaft And Crankshaft Position Sensors:

PURPOSE
The camshaft position sensor sends a signal to the Powertrain Control Module (PCM) which uses it as a "sync pulse" to trigger the injectors in proper sequence. The cam signal is not processed but passes through the ignition control module.

OPERATION
As the camshaft sprocket turns, a magnet in it activates the Hall-effect switch in the camshaft position sensor. When the Hall-effect switch is activated, it grounds the signal line to the PCM, pulling the cam signal line's applied voltage low. This is interpreted as a cam signal.

The cam signal is created as piston #1 is approximately 25° BTDC on the power stroke.