A decentralized fault diagnosis and accommodation scheme in discrete time for teams of cooperative mobile robots is presented. Each vehicle estimates, via a local observer, the overall state of the team, which is used to compute its local control input and a set of residual vectors. Each residual is sensible to a fault occurring on a single teammate, even not in direct communication, and the fault occurrence on a vehicle is declared if the corresponding residual exceeds a suitable adaptive threshold. Then, a recovery strategy, based on the estimate of the maximum detection time, is designed in order to remove the faulty teammates from the team and rearrange the mission. Numerical simulations, involving 5 vehicles moving in formation in a 3D environment, validate the proposed approach