A method for the active fault-tolerant control of discrete event systems modeled by deterministic Input/Output automata is proposed that can be applied if the diagnostic result consists of a set of fault candidates rather than a single fault. Based on the ambiguous diagnostic result a common model of the faulty plant is constructed that describes the identical part of the behavior of the plant under all fault candidates. Then the reconfiguration of the controller is performed based on this common model. It is proved that the resulting reconfigured tracking controller steers the faulty plant into the desired final state, no matter which fault actually occurred.