Method and system for determining a pressure/volume characteristic curve of a wheel brake in a motor vehicle brake system having an electrically controllable pressure supply device connected hydraulically to wheel brakes and can output a pressure medium volume for activating the wheel brakes. The pressure medium volume which is output by the pressure supply device can be determined. An electrically actuable inlet valve per wheel brake disconnects the connection between the wheel brake and the pressure supply device. During one or more service brake operations of the motor vehicle wheel brakes are activated by the pressure supply device, the pressure medium volume output by the pressure supply device in order to activate the wheel brakes is determined and the pressure/volume characteristic curves of the wheel brakes are determined on the basis of pressure medium volumes output by the pressure supply device during one or more service braking operations are determined.