Camshaft Position Sensor: Description and Operation

Camshaft Position (CMP) Sensor:

The Camshaft Position Sensor (CMP) sends a cam signal to the PCM which uses it as a sync pulse to trigger the injectors in proper sequence. The CAM signal is passed through the ignition control module. It is filtered and buffered by the ignition control module, but the signal is not processed in any other way. The PCM uses the CAM signal to indicate the position of the #1 piston during its power stroke. This allows the PCM to calculate true Sequential Fuel Injection (SFI) mode of operation. If the PCM detects an incorrect CAM signal while the engine is running, DTC P0341 will set.

If the CAM signal is lost while the engine is running, the fuel injection system will shift to a calculated sequential fuel injection mode based on the last fuel injection pulse, and the engine will continue to run. The engine can be restarted and will run in the calculated sequential mode as long as the fault is present with a 1 in 6 chance of injector sequence being correct.

The camshaft position sensor is located on the timing cover behind the water pump near the camshaft sprocket. 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 camshaft position sensor signal circuits applied voltage low. This is interpreted as a CMP Sensor signal. The CMP Sensor signal is created as piston #1 is approximately 25 after top dead center on the power stroke.