A method for exchanging data in messages between at least two users connected by a bus system, where each of the at least two users includes a predefinable and/or ascertainable timing mark, includes causing the at least two users to transmit, via the bus system, messages including the data. The method also includes causing a first user, in a function as timer, to control the messages as a function of time in such a way that it repeatedly transmits a reference message, which contains time information of the first user, via the bus at a specifiable time interval. Further, if the timing mark of the second user is reached without a reference message of the first user reaching the second user, the second user is caused to take over the function of timer by transmitting its own reference message with its own time information via the bus system.