Wireless sensor network and mobile ad hoc network are connected without using cable. Both are resource constrained systems that are often deployed in order to collect all the data. The problems are comes from failure of nodes, communication link, network breakage, energy depletion, disaster are inevitable situation for sending and receiving the data in WSN and MANET. So, the Fault tolerance techniques are one of the most important while sending and receiving the data in wireless networks. Many researchers has been proposed lot of fault tolerance mechanisms that are given a better performance to achieve higher data reliability, accuracy, energy saving and minimize failure of wireless networks.