The invention relates to an electronic stability control system and a method for detecting a fault of a motor freewheeling circuit. According to the invention, a freewheel switch and a reverse protection switch which are used for compensating counter electromotive force when a motor stops running during PWM control of a pump motor carried out by the electronic stability control system are used for detecting the fault. Disclosed herein is an electronic stability control system including: a motor driver configured to include a motor switch for driving a motor unit depending on a PWM signal and a freewheeling switch and a reverse protection switch for checking whether the motor unit is normally operated; and a controller configured to turn off all of the motor switch, the freewheeling switch, and the reverse protection switch, turn off only the motor switch and the reverse protection switch, or turn off only the motor switch and the freewheeling switch, apply a diagnostic current, and then detect a fault state of the freewheeling switch or the reverse protection switch, or the freewheeling switch and the reverse protection switch by using a voltage detector.