A method for exchanging data in a vehicle train having a tractor, at least one trailer coupled to the tractor, and vehicle electronics allocated to the tractor and trailer interconnected via a PLC data bus used to provide programmed input and output functions for the vehicle electronics of the trailer. Data representing the programmed functionality is provided automatically and cyclically via the PLC data bus to the vehicle electronics. The vehicle electronics can be configured as ABS control electronics, the programmed input and output functions providing functionality beyond that of the ABS function. Control of these additional functions in the trailer vehicle electronics equipped with the specific functionality is then exercised via an input/output unit provided in the tractor and connected to the PLC data bus either directly or indirectly via the tractor ABS control electronics.