A method and apparatus are provided for implementing a redundancy enhanced differential signal interface. A differential signaling I/O pair is coupled to a differential receiver interface. The differential receiver interface includes a pair of multiplexers coupled to a differential receiver. An error detecting mechanism is coupled to the differential receiver for detecting an error. When an error is detected, an interface operating speed is reduced. True and complement sides of a differential signaling I/O pair are alternately tested by first enabling a multiplexer control of one of the multiplexers, reading data, and checking for the error; then enabling a multiplexer control of the other multiplexer, reading data, and checking for the error. Responsive to detecting a failure of a true side or a complement side, the detected failed true side or complement side is set to a reference voltage and the reduced interface operating speed is maintained for continued operation.