In this paper, we propose a novel fault-tolerant algorithm for CAN protocol, called “Seamless CAN”. Its operation concept is based on High-availability Seamless Redundancy (HSR) implementation inside the in-vehicle network's ring structure and fault tolerance is achieved by encapsulating CAN frames inside HSR frames and sending them in a ring topology. Simulation results show that Seamless CAN provides better performance regarding no frame loss in case of link failures and a lower number of error occurrences.