Method for inspecting the vehicle state of a vehicle, in which inspections are performed on the execution, state, function and/or effect of the installed components and systems, wherein an adapter is used - to select an information source from a plurality of information sources, specifically controllers of a vehicle, a vehicle diagnostic interface, an EBS-CAN interface, a trailer light socket, sensors on the adapter, sensors outside the adapter, an external diagnostic apparatus or an external test bench that is functionally connected to vehicle components and whose respective configuration is known, a data connection is set up at the selected information source, using the known configuration, to an information sink, specifically the adapter and/or a computer connected to the adapter and/or an external analysis unit, and analysis is performed by way of a plausibility check on different data against one another or against reference values using the data from the information source, wherein - in the testing of a vehicle, information characterizing the vehicle type (A, B,...Z) and a list of the vehicle components to be tested is transmitted from an external computer to the adapter, - the adapter is connected to the vehicle diagnostic interface of the vehicle, - a controller of a vehicle component installed in the vehicle is addressed via the vehicle diagnostic interface, query commands are transmitted to said vehicle component and response signals resulting therefrom are processed within test sequences, in that - from the information characterizing the vehicle type (A, B,...Z) and the list of vehicle components to be tested, each of the vehicle components to be tested is tested in terms of installation by way of an installation file, process description file, first and second controller description file and first and second protocol description file, tested by way of the test sequences contained in the process description file following a successful installation test, and the result data including the response signals are stored in the adapter. - to select an information source from a plurality of information sources, specifically controllers of a vehicle, a vehicle diagnostic interface, an EBS-CAN interface, a trailer light socket, sensors on the adapter, sensors outside the adapter, an external diagnostic apparatus or an external test bench that is functionally connected to vehicle components and whose respective configuration is known, a data connection is set up at the selected information source, using the known configuration, to an information sink, specifically the adapter and/or a computer connected to the adapter and/or an external analysis unit, and analysis is performed by way of a plausibility check on different data against one another or against reference values using the data from the information source, wherein - in the testing of a vehicle, information characterizing the vehicle type (A, B,...Z) and a list of the vehicle components to be tested is transmitted from an external computer to the adapter, - the adapter is connected to the vehicle diagnostic interface of the vehicle, - a controller of a vehicle component installed in the vehicle is addressed via the vehicle diagnostic interface, query commands are transmitted to said vehicle component and response signals resulting therefrom are processed within test sequences, in that - from the information characterizing the vehicle type (A, B,...Z) and the list of vehicle components to be tested, each of the vehicle components to be tested is tested in terms of installation by way of an installation file, process description file, first and second controller description file and first and second protocol description file, tested by way of the test sequences contained in the process description file following a successful installation test, and the result data including the response signals are stored in the adapter.