Data bus system having a plurality of control units (1) which interchange messages with one another via a data bus (2) and which are provided for controlling components, the individual control units (1) being of modular design and being fitted in different installation spaces in a technical product, characterized in that the control units (1) are designed as distributed control units having individual modules (3, 4, 5a, 5b, 6), a plurality of which can be arranged independently of one another and some of which are connected via an internal data bus (7), and the individual modules (3, 4, 5a, 5b, 6) in a control unit produce data and signals for driving the same component/components (8, 9, 10, 11) with individual modules identical in terms of hardware being provided in different control units (1), and in that at least two different types of individual modules (3, 4, 5a, 5b, 6) are provided in a plurality of control units (1), with one output-stage individual module (5a, 5b) provided in a plurality of control units (1) being provided for the purpose of driving actuators and another logic individual module (4, 6) using a logic circuit or a microcomputer to produce digital input and output signals from digital information.