Camshaft Position (CMP) Sensor

CMP sensor is located at top of timing cover, behind water pump, near camshaft sprocket. As the camshaft sprocket turns, a magnet in it activates a Hall Effect switch in CMP sensor. This signal is generated whenever cylinder No. 1 is at TDC of its compression stroke.

This signal is used by PCM, in conjunction with signals from the 3X and 24X crankshaft position sensors, to fire ignition coils and trigger the fuel injectors in sequential firing order. If sensor should fail while engine is running, engine will continue to run using the last calculated CMP sensor signal to maintain sequential fuel injection mode. Upon restart, engine will run with a one in 6 chance of being correct. When incorrect, engine will run rough.