Radiator Cooling Fan: Description and Operation

Electric Fans

The 911 Turbo (997) is provided with a infinite fan control. The electric fans behind the radiators are controlled by the front-end control unit. The front-end control unit receives the information about the desired fan output (in %) via CAN from the DME control unit. The desired fan output is determined in the DME control unit on the basis of a program map as a function of the refrigerant pressure (CAN message from air-conditioning control unit) and engine water temperature. The requested output in % can be read out from the actual values with the PIWIS Tester (e.g. refrigerant pressure = 15 bar, tmot = 194 °F (90 °C) = greater than 50 %).