In the development and testing of complex technical systems, efficient methods are needed to verify quality and customer requirements. Model-based solutions, virtualization and simulation enable early validation of specific properties. This article describes the approach of virtual validation of fault tolerance using the simulation and virtual engineering framework FERAL, which has been extended to perform systematic fault injection at the levels of communication protocols and component implementation. The approach was evaluated in an industrial automation case study and demonstrated the identification and resolution of specific architectural design flaws in the system.