This paper presents a unified diagnosis method targeting most of the fault models used in practice today. This framework is intended to be used to diagnose faulty behaviors in nanometric circuits for which the classical stuck-at fault model is far to cover all realistic failures. The method is based on an Effect-Cause approach which relies on the two following main operations. The first one is based on critical path tracing (CPT) [4] and consists in identifying critical lines in the Circuit Under Test (CUT) which can be the source of observed errors. The second one consists in allocating a set of possible fault models to each critical line, so that root causes of failures can be finally determined. The main advantage of this method is that it does not need to explicitly consider each fault model during the diagnosis process.