Multistage networks play an important role in parallel-processing architectures and particularly in reconfigurable structures, as they provide the ability to switch paths between modules according to both the requirements of throughput and fault occurrence. In this respect, effective fault diagnosis techniques of these devices are highly desirable to cover these switching modes. In the paper diagnostic tests applicable to SW Banyan networks (SWBNs) with a spread of two and a fanout of two are presented.