Camshaft Position Sensor: Description and Operation

Fig 2 Camshaft Position Sensor:

Fig 3 Target Magnet:

Fig 4 Target Magnet Polarity:

PURPOSE
The PCM determines fuel injection synchronization and cylinder identification from inputs provided by the camshaft position sensor and crankshaft position sensor. From the two inputs, the PCM determines crankshaft position.

OPERATION
The camshaft position sensor attaches to the rear of the cylinder head (Fig. 2). A target magnet attaches to the rear of the camshaft and indexes to the correct position (Fig. 3). The target magnet has four different poles arranged in an asymmetrical pattern. As the target magnet rotates, the camshaft position sensor senses the change in polarity (Fig. 4). The sensor output switch switches from high (5.0 volts) to low (0.30 volts) as the target magnet rotates. When the north pole of the target magnet passes under the sensor, the output switches high. The sensor output switches low when the south pole of the target magnet passes underneath.

CIRCUIT OPERATION
Circuit K7 supplies 8 volts from the Powertrain Control Module (PCM) to the camshaft position sensor. The K7 circuit originates at cavity 44 of the PCM connector.

Circuit K44 from the sensor provides an input signal to the PCM. The K44 circuit connects to cavity 33 of the PCM.

The PCM provides ground for the camshaft position sensor signal (circuit K44) through circuit K4. Circuit K4 connects to cavity 43 of the PCM.

Helpful Information
Circuit K7 also splices to supply 8 volts to the crankshaft position sensor and vehicle speed sensor.

Circuit K4 also splices to supply ground for the signals from the following:
- Upstream heated oxygen sensor
- Downstream heated oxygen sensor
- Crankshaft position sensor
- Throttle position sensor
- Manifold absolute pressure sensor
- Engine coolant temperature sensor
- Knock sensor
- Intake air temperature sensor
- Vehicle speed sensor