Park your car, and either turn it on into accessory or turn it all the way on. Make sure the parking break is on, and then on the gauge cluster screen navigate to User Settings>Other>Fuel Econ. Unit, then you should be able to adjust the fuel econ unit. I have a U.S. car and the only options I get is U.S. Gallon and U.K. Gallon, however you should be able to change it there.