Disclosed is a method, including: urgently putting a brake on a vehicle; detecting current values for at least two phases among phases of a motor which operates at a current which is out of a current measurable range through the urgently putting of a brake; comparing the current value detected in the detecting with a threshold value; when it is determined that there is one current value which is equal to or higher than the threshold value among the detected current values in the comparing, removing the current value which is equal to or higher than the threshold value and obtaining a current value for the remaining phase of the motor from a predetermined look-up table; and determining the removed current value using a current value which is detected through the comparing and is lower than the threshold value and the current value obtained through the obtaining.