The steering system with its challenging functions has to be successfully integrated and interlinked in the whole vehicle, with implementation and validation preferably occurring as early as possible. It is important to evaluate subjective criteria and translate them into objective criteria. The used X-in-the-Loop method stands for the seamless inclusion of all relevant components and systems - model, software and hardware - in the whole vehicle. As important functions have to be tested and validated, e. g. ADAS, the whole vehicle has to be examined in realistic driving situations.