Apparatus and methods for locating faults in inductively coupled wired drill pipe while drilling. In one embodiment, apparatus includes a drill string and a wired drill pipe fault monitor. The drill string includes a plurality of wired drill pipes. Each wired drill pipe includes an inductive coupler at each terminal end. The wired drill pipe fault monitor is coupled to the wired drill pipes. The fault monitor includes an impedance measuring system and a fault locator. The impedance measuring system is configured to measure, while drilling the borehole, an input impedance of the wired drill pipes. The fault locator is configured to determine a propagation constant for the wired drill pipes, and to analyze the measured input impedance and determine, as a function of the measured input impedance and the propagation constant, a location of a fault in the wired drill pipes.