Due to wireless communication, dynamic topology, limited resources and lack of centralized administration, MANETs are vulnerable to various types of DoS attacks on network layer. In Gray hole and Black hole attacks malicious nodes deliberately disrupt data transmission in the network by sending incorrect routing information. It is a challenge to keep the communication route free from such attackers. In this paper, we propose a scheme for Ad-hoc On-demand Distance Vector (AODV) protocol, in which an intermediate node detects the malicious node sending false routing information, routing packets are used not only to pass routing information, but also to pass information about malicious nodes. The proposed scheme not only detects but also removes malicious node by isolating it, to make safe and secure communication.