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.