Method for data transmission between at least two digitally controllable vehicle components (1a, 1b, 1c), each vehicle component (1a, 1b, 1c) comprising an electronic control unit with - a monitoring unit, - two communication interfaces (4a, 4b), namely a first and a second communication interface, and - an interface switch for determining a division of the data to be transmitted between the communication interfaces (4a, 4b), the monitoring unit being set up to monitor the communication interfaces (4a, 4b), the at least two vehicle components (1a, 1b, 1c) being connected to one another for the purpose of exchanging data by providing two data connection lines (5a, 5b) in each case between the vehicle components, the first communication interfaces being connected to one another by a first data connection line and the second communication interfaces being connected to one another by a second data connection line, comprising the following steps: a) continuously checking the data connection between the vehicle components by means of the monitoring units provided for this purpose and distinguishing between a normal state and an error state, wherein in a normal state both data connection lines (5a, 5b) are available with their nominal bandwidth, and in an error state the data exchange via one of the two data connection lines (5a, 5b) fails for lack of existence of a data connection, b) when a normal state is detected, dividing a standard data stream to be exchanged between the vehicle components (1a, 1b, 1c) between the two data link lines (5a, 5b) by means of the interface switch in order to use the bandwidth of both data link lines (5a, 5b) simultaneously and to prevent any failure of a data link line (5a, 5b) can be detected immediately on the basis of the detection of a data failure, the standard data stream comprising safety-relevant data and also non-safety-relevant data and information being available at the vehicle components with regard to the structure of the standard data stream, so that a data failure is detected by comparison with the known structure of the standard data stream, c) when the fault state of a data link is detected, disconnecting the faulty data link (5a, 5b) from the transmission of the standard data stream by changing the splitting by means of the interface switch and changing the activation of the remaining data link (5a, 5b) such that the transmission of the safety-related data is prioritized over the transmission of the safety-irrelevant data, wherein, when the fault state is detected, a safety routine is triggered in the course of which the data link affected by the faulty transmission is electrically disconnected from the vehicle components (1a, 1b) concerned, wherein the data links (5a, 5b, 5c, 5d) are part of a data bus system, this being a CAN, CAN-FD or automotive Ethernet bus system, wherein safety-relevant data of the standard data stream concern data for controlling at least one of the following vehicle headlamp lighting functions: {position light; daytime running light; static low beam; direction indicator}. - a monitoring unit, - two communication interfaces (4a, 4b), namely a first and a second communication interface, and - an interface switch for determining a division of the data to be transmitted between the communication interfaces (4a, 4b), a) continuously checking the data connection between the vehicle components by means of the monitoring units provided for this purpose and distinguishing between a normal state and an error state, wherein in a normal state both data connection lines (5a, 5b) are available with their nominal bandwidth, and in an error state the data exchange via one of the two data connection lines (5a, 5b) fails for lack of existence of a data connection, b) when a normal state is detected, dividing a standard data stream to be exchanged between the vehicle components (1a, 1b, 1c) between the two data link lines (5a, 5b) by means of the interface switch in order to use the bandwidth of both data link lines (5a, 5b) simultaneously and to prevent any failure of a data link line (5a, 5b) can be detected immediately on the basis of the detection of a data failure, the standard data stream comprising safety-relevant data and also non-safety-relevant data and information being available at the vehicle components with regard to the structure of the standard data stream, so that a data failure is detected by comparison with the known structure of the standard data stream, c) when the fault state of a data link is detected, disconnecting the faulty data link (5a, 5b) from the transmission of the standard data stream by changing the splitting by means of the interface switch and changing the activation of the remaining data link (5a, 5b) such that the transmission of the safety-related data is prioritized over the transmission of the safety-irrelevant data,