The radiator shutter seals off the engine compartment from the outside and directs the cooling air under the engine.
The pressure converter connects the vacuum unit with the vacuum supply by means of hoses. When activated by the DDE control unit, the pressure converter switches vacuum through to the vacuum unit and the radiator shutter closes (= standard setting).
The radiator shutter is opened at:
If a defect occurs in the pressure converter activation function, fault code 56 "radiator shutter" is stored and the radiator shutter opens (provided there is no additional mechanical defect to jam the radiator shutter).