In this article a novel Control Barrier Function (CBF) named the fault tolerant Control Barrier Function (ftCBF) is introduced. The ftCBF is able to keep a vehicle within a predefined safe set with changing control bounds and changing system dynamics. The ftCBF is shown to be feasible in fault tolerant control applications, as opposed to existing CBF methods. This novel constraint is tested on a double integrator system, and on a non-linear Dubin’s Car system with changing system dynamics and changing control bounds. In the simulations it is shown that the ftCBF is able to keep the vehicle in the safe set with failure events occurring at any place in the timeline. The ftCBF contains design parameters that allow a trade-off between safety and performance.