ELECTRONIC BRAKE SYSTEM

The present disclosure relates to a control method of a brake system including a reservoir in which oil is stored, wherein the control method includes detecting a first level of a liquid level of oil stored in the reservoir, detecting a second level of the liquid level of oil stored in the reservoir, determining a decrease trend of an oil amount stored in the reservoir based on a time point when the first level is detected and a time point when the second level is detected, and limiting at least one additional function based on the decrease trend of the oil amount.