RAM 1500 Truck 2WD V8-4.7L VIN N (2002)
Camshaft Position Sensor: Description and Operation
The Camshaft Position Sensor (CMP) on the 4.7L V-8 engine is bolted to the right-front side of the right cylinder head.
Fig. 5 CMP And Tonewheel Operation - 4.7L
The Camshaft Position Sensor (CMP) sensor on the 4.7L V-8 engine contains a hall effect device called a sync signal generator that is used to generate a
fuel sync signal. This sync signal generator detects notches located on a tonewheel. The tonewheel is a rotating target wheel and is located at the front of
the camshaft for the right cylinder head. As the tonewheel rotates, the notches pass through the sync signal generator. The pattern of notches (viewed
counter-clockwise from the front of the engine) is: 1 notch, 2 notches, 3 notches, 3 notches, 2 notches, 1 notch, 3 notches and 1 notch. The signal from
the CMP sensor is used in conjunction with the Crankshaft Position Sensor (CKP) to differentiate between fuel injection and spark events. It is also used
to synchronize the fuel injectors with their respective cylinders.
When the leading edge of the tonewheel notch enters the tip of the CMP, the interruption of magnetic field causes the voltage to switch high, resulting in
a sync signal of approximately 5 volts.
When the trailing edge of the tonewheel notch leaves then tip of the CMP; the change of the magnetic field causes the sync signal voltage to switch low
to 0 volts.
