Differential lock transfer box or Front wheel drive unexpected speed difference.
Check sensors, connectors and wiring. Check the mechanical parts of the differential lock.Check the tachograph configuration.
What you'll see
No driver-visible symptom recorded.
System reaction
The driver is given an indication that the differential lock is engaged despite it not working. This fault code is generated if any of the wheels are slipping.
Diagnostic depth
The front axle speed and the vehicle speed are not the same despite the solenoid valve for the differential lock or front wheel drive being active and the position sensor confirming that the differential lock in the transfer gearbox or front wheel drive is engaged.
Mechanical defect in differential lock, short circuit in sensor or wiring for sensor. Sensors may have been mixed up.The tachograph may have wrong configuration.