2005 Mercury Mariner 3.0 1, FWDFACTORY OEM SERVICE PROCEDURE

Camshaft Position (CMP) Sensor

The 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 PCM and used for synchronizing the sequential firing of the fuel injectors. Coil-on-plug (COP) ignition applications 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 2 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 2 types of CMP sensors: the 3-pin connector Hall-effect type sensor (only used on F-150 4.2L applications) and the 2 pin connector variable reluctance type sensor used on all other vehicle applications.

Fig 1: F-150 4.2L Hall-Effect CMP Sensor
G03877882Courtesy of FORD MOTOR CO.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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