22 · Diagnostics

Electric fan stays on all the time

Fault diagnosisElectric fan stays on all the time

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.

1	CHECK WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
		Results of the tests
	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 2	An error is detected in the control unit	Continue according to the instructions for the diagnostic equipment
2	FAN OPERATING CIRCUIT CHECK	All OK	Problems met	Operation
	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 3	Connections not correct	Restore the connections
			Component defective	Replace the component involved (if a fuse is involved, search for the cause of the problem)
			Engine management control unit faulty	Carry out a thorough check on the control unit (using diagnostic equipment - Examiner or other instruments) and, if necessary, replace the engine control unit
3	CHECKING CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Search for the fault starting from another symptom'

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