In this paper we present a new efficient online routing error detection approach dedicated to fault tolerant routing algorithms for the 2-D mesh reconfigurable Network-on-Chip interconnections. The main contribution is to distinguish a routing error due to switching failure from an adaptative routing decision (bypassing a faulty area or reconfigurable region in the NoC). The originality of our approach is that it can be applied to all adaptative routing based on modified turn model and well known XY algorithm, and allows the routing of messages in the networks incorporating the regions not necessarily rectangular.