Recently, robotics technology has been applied to tasks executed in unstructured and hazardous environments where fault tolerance is essential. In distributed robotic teams, a fault in one robot or in the communication system could cause a catastrophic failure of the whole team. In this talk, we will discuss the problem of fault tolerance in the Millibots. Faults affecting the localization of one robot could cause an error of positioning and mapping in the whole team. We will discuss a fault tolerance scheme, in which faults are first detected and isolated after which the localization procedure is reconfigured.