An electronic device having a self diagnosis function, the electronic device comprising: a display; an interface configured to receive a user's selection signal for a connection hardware of an object to be diagnosed, said object being a component of the electronic device; and a controller (200, 210) configured to: control the display to display a list of the connection hardware of the object to be diagnosed, in response to receiving the user input for selecting one connection hardware in the displayed list of the connection hardware of the object through the interface, provide a plurality of lines connected to the selected connection hardware of the object to be diagnosed with a signal for diagnosis, and calculate a diagnosis result for the selected connection hardware of the object to be diagnosed according to a result of comparison of the signal for diagnosis with a return signal which is returned from the selected connection hardware to be diagnosed by a loop-back operation, wherein the connection hardware of the object to be diagnosed is at least one of a first connector connectable to an external device or a cap (410, 420) such that it forms a first loop-back by connecting the cap to the first connector so as to make a return path, and a second connector provided in a circuit board and connected to the controller such that it forms a second loop-back so as to make a return path, wherein the signal for diagnosis has different values of a DC voltage or a frequency for each line of the plurality of lines, and is provided to the plurality of lines simultaneously. a display; an interface configured to receive a user's selection signal for a connection hardware of an object to be diagnosed, said object being a component of the electronic device; and a controller (200, 210) configured to: control the display to display a list of the connection hardware of the object to be diagnosed, in response to receiving the user input for selecting one connection hardware in the displayed list of the connection hardware of the object through the interface, provide a plurality of lines connected to the selected connection hardware of the object to be diagnosed with a signal for diagnosis, and calculate a diagnosis result for the selected connection hardware of the object to be diagnosed according to a result of comparison of the signal for diagnosis with a return signal which is returned from the selected connection hardware to be diagnosed by a loop-back operation, wherein the connection hardware of the object to be diagnosed is at least one of a first connector connectable to an external device or a cap (410, 420) such that it forms a first loop-back by connecting the cap to the first connector so as to make a return path, and a second connector provided in a circuit board and connected to the controller such that it forms a second loop-back so as to make a return path, wherein the signal for diagnosis has different values of a DC voltage or a frequency for each line of the plurality of lines, and is provided to the plurality of lines simultaneously. control the display to display a list of the connection hardware of the object to be diagnosed, in response to receiving the user input for selecting one connection hardware in the displayed list of the connection hardware of the object through the interface, provide a plurality of lines connected to the selected connection hardware of the object to be diagnosed with a signal for diagnosis, and calculate a diagnosis result for the selected connection hardware of the object to be diagnosed according to a result of comparison of the signal for diagnosis with a return signal which is returned from the selected connection hardware to be diagnosed by a loop-back operation, wherein the connection hardware of the object to be diagnosed is at least one of a first connector connectable to an external device or a cap (410, 420) such that it forms a first loop-back by connecting the cap to the first connector so as to make a return path, and a second connector provided in a circuit board and connected to the controller such that it forms a second loop-back so as to make a return path, wherein the signal for diagnosis has different values of a DC voltage or a frequency for each line of the plurality of lines, and is provided to the plurality of lines simultaneously.