2888343 - D33 ELECTRIC FAN STAYS ON ALL THE TIME

The cooling fan comes on when the temperature of the engine coolant is high, but then does not switch off, even when the engine is cold.
Results of the tests
1CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket

Check

  • that there are no faults in the engine management control unit
  • plausibility of all the parameters
Continue to Step 2An error is detected in the control unitContinue according to the instructions for the diagnostic equipment
2FAN OPERATING CIRCUIT CHECKAll OKProblems metOperation

Check, in order:

  • fan engagement relay
  • connection between engine management control unit and fan relay
  • connection between relay and fan ( See   E5020  ENGINE COOLING )
Continue to Step 3Connections not correctRestore the connections
Component defectiveReplace the component involved (if a fuse is involved, search for the cause of the problem)
Engine management control unit faultyCarry out a thorough check on the control unit (using diagnostic equipment - Examiner or other instruments) and, if necessary, replace the engine control unit
3CHECKING CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persistsSearch for the fault starting from another symptom'