Fuel tank for a vehicle comprising a filler neck for receiving a diesel fuel filler nozzle

The fuel tank has a filling connection sized for reception of a large-diameter filling gun for supplying diesel fuel. The connection contains a blocking valve, preventing filling of the fuel tank upon insertion of a filling gun of lesser diameter. The blocking valve is opened via a sensor identifying the insertion of the large-diameter filling gun, to provide a connection between the filling connection and the interior of the fuel tank. The blocking valve is electromagnetically-operated, the sensor provided by an electromagnetic sensor or a Hall sensor.