A method for nondestructive and noncontact detection of faults in a test piece, with a transmitter coil arrangement with at least one transmitter coil which transmitter coil is used to bring a plurality of periodic electromagnetical AC fields to a test piece, a receiver coil arrangement with at least one receiver coil for detecting a periodic electrical signal which has a carrier oscillation whose amplitude and/or phase is modulated by a fault in the test piece. A signal processing unit producing a useful signal from the receiver coil signal, and an evaluation unit evaluating the useful signal for detection of a fault in the test piece. A self-test unit automatically or upon an external request undertakes systematic quantitative checking of signal processing functions of the signal processing unit and/or systematic quantitative checking of the transmitter coil arrangement and/or of the receiver coil arrangement and/or upon external request undertakes calibration of the signal processing unit using a calibrati
