Interleaved DC-DC converters are prevalent in many applications like wind turbine systems, photovoltaic energy systems, and hybrid electric vehicles, for their characteristics of high conversion efficiency and low current ripple. Motivated by the increasing requirement of system reliability, fault diagnosis and tolerant strategies for this topology have become a topic of concern. Throughout the present works in this topic, single-phase fault is mainly discussed, which does not cover all the potential scenarios of a system. Furthermore, most methods are based on a certain number of phases structure, leading to a restricted generality. To solve the above problems, this paper proposes an open-circuit fault diagnosis method for interleaved DC-DC converters with any phases number. Without using additional sensors, the method sharing signals with a control unit can detect faults and locate more than one faulty phases. Simulation and experimental results based on a four-phases interleaved DC-DC converter confirm the effectiveness of the method.