Abstract: The invention relates to a device for monitoring errors in undercarriage components of rail vehicles, having at least one acceleration sensor which works with an evaluation unit. At least one acceleration sensor is arranged on the undercarriage of the rail vehicle in such a manner that its direction of detection has at least one component parallel to the vertical axis (z-direction) of the rail vehicle. The invention proposes that the acceleration sensor is constructed in such a manner that it delivers a measuring signal which contains the signal portion corresponding to a ground acceleration, or represents a signal corresponding to a ground acceleration, and that the evaluation unit has a routine for testing functions of the acceleration sensor, the routine controlling an error signal if the measuring signal delivered by the acceleration sensor contains no signal portion corresponding to a ground acceleration. The routine also suppresses the error signal if this is not the case.