During last years, the Time-Triggered Architecture (TTA) has been gaining acceptance as a generic architecture for highly dependable real-time systems. It is now being used to implement the "x-by-wire" concept. A problem for this kind of systems is their validation. Fault Injection has achieved a great acceptance among designers for the experimental validation of systems. This work describes the results and experiences obtained during the validation of the TTP/C controller, a communication controller based on the TTA. Two different fault-injection techniques have been used: VHDL-based fault injection and physical fault injection at pin level. Due to the access that each technique has to different parts of the system, they can complement each other, but moreover, some experiments can be reproduced using both techniques, being very helpful for the analysis of the results.