Cooling Fan Speed Control
WARNING: This page is about a different car, the 2004 Infiniti M45. However, it is still accessible from the selected car via links, so may be relevant.
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.