The invention relates to an apparatus for automatic ejection of a fluid, having a drive train for automatically ejecting the fluid from a fluid reservoir through an ejection channel, and having a control unit (510) for controlling the apparatus, the control unit (510) being configured to detect failures of drive train actuation steps (610, 620), during which the drive train is actuated for priming or fluid dose ejection, the control unit (510) being further configured to control the apparatus as a function of an actuation step failure number, the actuation step failure number being the number of failed drive train actuation steps (610, 620) since the last successful drive train actuation step (610, 620). The invention further relates to a system comprising such an apparatus a disposable assembly attachable to the apparatus and to a method for controlling such an apparatus.
