Method and device for transferring fuel from the fuel tank of a motor vehicle

The method involves connecting a diagnosis test device (4) with a control device (8) of a motor car (2) over a single or multi-pole data line (10). The control device is controlled by the diagnosis test device based on a fuel tank filling signal for driving a fuel pump of the motor car by the control device such that the fuel pump conveys fuel from a fuel tank of the motor car. An outlet of the fuel pump is connected with an external container before the controlling of the control device, where the filling signal is transmitted over a controller area network-bus of the motor car. An independent claim is also included for a diagnosis test device for a motor car.