The present disclosure provides a method for operating an injector of an internal combustion engine, the nozzle needle of said injector being operated by a piezo actuator by means of a servo valve. The method may include eliminating the idle travel of the piezo actuator by maintaining a permanent direct force connection between the piezo actuator and the servo valve, so that a change in force on the servo valve due to a change in pressure in the valve chamber when the servo valve is opened and closed and when the nozzle needle of the injector is closed is always transmitted to the piezo actuator as a change in force, detecting the resulting change in voltage and/or capacitance of the piezo actuator, and ascertaining parameters with which the injection quantity which is output by the injector is regulated based on the result of the detection.