In this paper, hybrid observers based approach for faults detection and isolation, for a class of MIMO hybrid systems, is proposed. The faults herein considered can affect the sensors or the discrete trajectory of the considered system. The proposed approach is based on a Dedicated Switched Robust Observer Scheme (DSROS) using three blocks in interaction. A block for the mode signatures, a block for the fault signature a block for the diagnosis of the discrete events. Some LMIs conditions are provided to guarantee both of the robustness and the convergence of the proposed observers. Finally some simulation results illustrate the efficiency of the proposed approach.