Abstract: A method for flashing air from an injection valve such as a common rail injector for an internal combustion engine which injection valve on being put into operation is initially at least partly filled with air and to which a liquid medium is supplied via a typical connection for supplying fuel, including pressurizing an inner chamber of the injection valve to a pressure that is reduced compared to normal operation, whereby existing air bubbles increase in volume compared to the volume in normal operation, and flushing the medium contained in the aforementioned inner chamber at a reduced pressure that remains at least approximately constant, and selectively repeating these steps multiple times. The operational readiness of the injector, despite air in the gas phase that is initially contained inside it in the liquid medium, can be brought about rapidly as a result. An apparatus for performing the method is also disclosed.