A sensor diagnostic system includes a first sensor configured to receive a reflected signal that corresponds to a portion of a transmitted signal transmitted from a second sensor and reflected from a surface, a wavelength determination module configured to determine a first wavelength of the reflected signal that is indicative of a second wavelength of the transmitted signal, a wavelength shift detection module configured to determine a shift in at least one of the first wavelength and the second wavelength, and a sensor health analysis module configured to perform diagnostics on the second sensor based on the determined shift.