Camshaft Position Sensor: Operation: 4.0L

The CMP sensor (1) uses a rotating hall effect device called a target wheel (3) which is attached to the oil pump drive shaft. The target wheel contains sets of machined notches (2). See Fig 1.

When the leading edge of a target wheel notch passes by the tip of the CMP sensor, 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 target wheel notch passes by the tip of the CMP sensor, the change of the magnetic field causes the sync signal voltage to switch low to 0 volts.

Fig 1: 4.0L CMP Operation

Courtesy of DAIMLERCHRYSLER CORP.