Radiator Cooling Fan Control Module: Description and Operation

ENGINE OVER TEMPERATURE




SYSTEM DESCRIPTION
This system controls the cooling fan operating speed. The opening of the cooling fan speed control solenoid valve changes to control oil pressure provided to the cooling fan drive pump.

This system consists of the cooling fan pump, cooling fan drive pump, cooling fan speed control solenoid valve, oil cooler, cooling fan fluid reservoir, etc.

The cooling fan pump is operated by engine with the drive belts and provides oil pressure to the cooling fan drive pump which operates the cooling fan. The cooling fan speed control solenoid valve is installed between the cooling fan pump and cooling fan drive pump. The solenoid valve repeats ON/OFF operation according to the signal sent from the ECM. The opening of the solenoid valve varies for optimum engine control. The optimum value stored in the ECM is determined by considering various engine conditions.




COOLING FAN SPEED CONTROL
The ECM controls the cooling fan speed corresponding to the engine speed, the radiator coolant temperature, refrigerant pressure, vehicle speed, air conditioner switch signal, etc.

The ECM determines the target fan speed based on the basic fan speed considering the radiator coolant temperature and the engine speed. The ECM controls fan speed between 0 to 2,550 rpm.

When the cooling fan speed control solenoid valve is malfunctioning (does not operate), the cooling fan is operated at the maximum speed by engine through the drive belts.







Cooling Fan Basic Speed