The reliability assessment of complex active systems requires simulation methods, which reproduce complex system performance and also account for failure and fatigue scenarios. More and more, test methods traditionally carried out experimentally are replaced by computational or 'virtual' methods. Reliability of these complex adaptive systems is hard to estimate for several reasons. A priori undetermined interaction between various influencing parameters, unknown fatigue properties of the multifunctional materials employed in sensors and actuators and very complex system performance requirements make it difficult to predict under which circumstances the system may fail. Sensitivity Analysis (SA) of the comprehensive adaptive system model has proven to be a valuable tool for the identification and assessment of scenarios that are relevant for system reliability. For the example of an active oil pan, which is equipped with piezoelectric sensors and actuators to suppress structural vibrations, the method is outlined.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.