A method of detecting data transmission errors in a CAN controller includes generating at least one check bit that is verifiable for ensuring the consistency of the transmitted data. A CAN controller that ensures continuous error monitoring during data transmission includes an interface unit for exchanging data with a CAN bus, a memory unit for storing received data and data to be transmitted, and an electronic unit for controlling data transmission between the memory unit and the interface unit. The interface unit of the CAN controller has an arrangement for generating check bits for received data and for verifying check bits for data to be transmitted.