3233022 - D31 ENGINE OVERHEATING / WITH FAN NOT WORKING

The reading on the instrument in the panel shows a high engine coolant temperature and the cooling fan does not come on
Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation
Check the condition and the correct operation of the engine cooling fan(s)
this check can be carried out by connecting the diagnostic equipment (Examiner or other instruments) to the diagnostic socket and carrying out the active diagnosis of the engine cooling fans:(in the engine management control unit ambient)
Continue to Step 2 Fan(s) faulty Continue to Step 1
1FAN OPERATING CIRCUIT CHECKAll OKProblems metOperation

Check, in order:

  • fan fuses
  • fan engagment relays
  • fan resistances
  • connection between management control unit and fan relays
  • connection between fan relays and fans ( See   E5020  ENGINE COOLING ).
Continue to Step 2 Connections not correctRestore the connections
Component defectiveReplace the component involved (if a fuse is involved, search for the cause of the problem)
Fan resistances faultyNOTE in that case the fan is not working at two different speeds Replace the fan resistances Op.   1088E20 
Fan(s) faulty Replace fan(s) Op.   1088E11 
2CHECK CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persistsSearch for the fault starting from another symptom'