COOLING FAN SYSTEM PROBLEM SYMPTOMS TABLE

Tech Tips

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

Cooling Fan System
Symptom Suspected Area See page
Cooling fans do not operate (main and sub fans) Engine coolant temperature sensor

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Cooling fan circuit

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ECM

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Cooling fan does not operate (main fan) Cooling fan motor (for main fan)

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RDI FAN NO. 1 relay

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Cooling fan circuit

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Cooling fan ECU (for main fan)

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Cooling fan does not operate (sub fan) No. 2 cooling fan motor (for sub fan)

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RDI FAN NO. 2 relay

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Cooling fan circuit

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Cooling fan ECU (for sub fan)

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Cooling fans do not stop (continues to operate ) (main and sub fans) Engine coolant temperature sensor

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Cooling fan circuit (open in SI and SI2 circuit)

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ECM

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Cooling fan does not stop (continues to operate) (main fan) Cooling fan circuit (open in SI circuit)

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Cooling fan ECU (for main fan)

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Cooling fan does not stop (continues to operate ) (sub fan) Cooling fan circuit (open in SI2 circuit)

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Cooling fan ECU (for sub fan)

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Cooling fan speed does not change Cooling fan circuit

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ECM

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