applying first different voltages to pixels included in a reference pixel column and pixels included in a pad adjacent pixel column electrically connected to a second pad adjacent to a first pad electrically connected to the reference pixel column;

applying second different voltages to the pixels included in the reference pixel column and pixels included in a line adjacent pixel column electrically connected to a second data line adjacent to a first data line electrically connected to the reference pixel column;

detecting whether the short exists between the first pad and the second pad based on luminance of the pixels included in the reference pixel column and luminance of the pixels included in the pad adjacent pixel column; and

detecting whether the short exists between the first data line and the second data line based on the luminance of the pixels included in the reference pixel column and luminance of the pixels included in the line adjacent pixel column.