The advantageous embodiments provide a method, a computer program product, and an apparatus for monitoring a wiring system. A number of responses to signals transmitted in a portion of the wiring system are measured to form a measured signature. Design data for the portion of the wiring system is retrieved. A number of expected responses for the signals in the portion of the wiring system are identified using the design data to form a computed signature. The measured signature is compared with the computed signature.