Nowadays, better driving also means better braking. To this end, vehicle designers must find all failures during the design phase of antilock braking systems which play an important role in automobiles safety. However, mechatronic systems are so complex and failures can be badly identified. So it is necessary to propose a design approach of an antilock braking system which will be able to avoid wheels locking during braking and maintain vehicle stability. This paper describes this approach, in which we model the functional and the dysfunctional behavior of an antilock braking system using stopwatch Petri nets.