an apparatus having a self - aspirating pump , with which , in a traction control mode , pressure fluid can be aspirated through an intake line from a pressure fluid supply tank of a master brake cylinder . located in the intake line is a control valve that assumes its preferred blocking positoin and can then be switched into its open position by a pressure pulse generated by the pump , through a control line . this open position can be switched whenever a control valve , located in the brake line of the master brake cylinder , is switched by an electronic control unit of the control apparatus out of its preferred position thereby connecting the master brake cylinder to the wheel brake cylinders into another position , thereby carrying pump pressure to the control valve . aspiration of pressure fluid from the supply tank is thus avoided upon pump startup with undesirable feeding . this prevents the production of noise from the pumping of pressure fluids into the master brake cylinder .