Control devices in a motor vehicle, having first sequence-controlled control devices being connected to a first data bus and second sequence-controlled control devices being connected to a second data bus, are networked. A first control device sends a first message via the gateway device into the first and second data buses. At least a second control device receives the first message and checks whether the receiving of the first message is required for the corresponding control device. The second control device sends out a response message, which indicates whether the second control device has a corresponding need to receive the first message. In the event of such a need, a routing default is established and/or an existing routing default is changed in a gateway device.