This paper presents the process of qualitative multi-faults diagnosis. We propose a new diagnostic process for continuous and dynamic system and its corresponding consistency-checking module. The STRIPS language is used to generate the system model since it integrates the cause- effect information required to process the diagnosis. With the STRIPS language, actions are described in terms of their preconditions and effects and states are formulated as conjunctions of positive literals. A diagnosis is established when assuming particular components to be faulty and others to be normally functioning restore consistency. It reasons about multiple faults or causes for an abnormality by testing an assumption if it leads to an inconsistency. The main contribution is to realize the qualitative multi-faults diagnosis without requiring detail and precise knowledge about faulty components and without the impossible diagnoses.