4.2.321. SPN 723, FMI 31, Cam speed sensor signal missingΒΆ

Description

The system has not been able to detect any signals from the camshaft sensor.

Possible causes are:

  • An invalid signal or no signal from the camshaft sensor.
  • The sensor wiring is defective (signal lines reversed)
  • The sensor is defective
  • The trigger wheel is defective

Reaction in EEM

The FC is stored and the warning lamp is activated. The CAN message indicates active fault. Engine power will be reduced (Degradation Level 2). The engine starting may take longer than normally, and the running may be poor due to missing/incorrect information for the injection timing control. The engine runs with the crankshaft speed sensor signal.

Solution

First save the error log and then erase it. Restart the ECU after erasing the error log. If the fault occurs again during the next driving cycle, check the following paths:

  • Check the camshaft sensor wiring, the connectors and the contact surfaces of the connector pins (possible oxidation). Look also for a possible reverse connection.
  • Check the camshaft sensor mounting. The air gap between the sensor tip and the trigger wheel teeth should be 0,2 - 1,0 mm.
  • Look for possible electromagnetic noise sources on or close to the vehicle, disturbing the speed sensor signal (devices using or carrying high currents, high voltages or strong magnetic fields).
  • Check the condition and the mounting of the camshaft trigger wheel (damaged teeth, the positioning of the trigger wheel).
  • Check the operation with another camshaft speed sensor to see if the sensor is defective.

See Camshaft inductive speed sensor details for EDC17CV54 ECU reference.

See Camshaft HALL speed sensor details for EDC17CV63 ECU reference.