DIAGNOSEVERFAHREN UND DIAGNOSEVORRICHTUNG ZUR FUNKTIONSORIENTIERTEN DIAGNOSE EINES SYSTEMS MIT VERNETZTEN KOMPONENTEN

The invention relates to a diagnostic method and a diagnostic device (100) for a system (1), especially a motor vehicle system, comprising components (2) that are interconnected and supply functions for the system (1). A component diagnosis data set (54) encompassing diagnostic entities for the respective component (2) and function allocation entries is provided for each system (1) component (2), the function allocation entries indicating allocations of the diagnostic entities to the functions. The diagnostic method comprises the following steps: the component diagnosis data sets (54) of the system (1) components (2) are determined (57); the determined component diagnosis data sets (54) are transformed (58) into one or several function diagnosis data sets, each of which encompasses at least the diagnostic entity entries of all diagnostic entities of a type of diagnostic entity allocated to one of the functions; a function-related diagnosis request is detected and diagnostic data is supplied (61) based on the diagnosis request and at least one of the function diagnosis data sets. The inventive diagnostic device (100) comprises an input unit (124) for detecting a function-related diagnosis request, an interface (104) for exchanging data with the system (1) components (2), a control unit for determining the component diagnosis data sets (54) of the system (1) components (2), a transformation unit for transforming (58) the determined component diagnosis data sets (54) into one or several function diagnosis data sets, and a supply unit for providing (61) diagnostic data based on the diagnosis request and at least one of the function diagnosis data sets.