Camshaft Position Sensor: Description and Operation

CAMSHAFT POSITION SENSOR

Typical Hall-Effect Sensor:

Typical Variable Reluctance Sensor:

The camshaft position (CMP) sensor detects the position of the camshaft. The CMP sensor identifies when piston No.1 is on its compression stroke. A signal is then sent to the powertrain control module (PCM) and used for synchronizing the sequential firing of the fuel injectors. The Coil On Plug (COP) ignition applications also use the CMP signal to select the proper ignition coil to fire. The input circuit to the PCM is referred to as the CMP input or circuit. DTC P0340 is associated with this sensor.

Vehicles with two CMP sensors are equipped with variable camshaft timing (VCT). They use the second sensor to identify the position of the camshaft on bank 2 as an input to the PCM. DTC P0345 is associated with this sensor and it is referred to as CMP2.

There are two types of CMP sensors: the three pin connector Hall-effect type sensor (Figure 28) found on F-Series 4.2L applications, and the two pin connector variable reluctance sensor found on all other vehicles (Figure 29).