The codes you have indicate an open circuit for the TFT sensor. It is recommended that you actually test them with an ohm meter to prevent un-necessary repairs that could eventually lead to future problems. Overlaying a circuit is acceptable if done properly and you seem to understand that. Begin with testing from the PCM to the transmission connector. If the harness is chaffed and one of the TFT wires is damaged it is likely that other wires are also affected. If that is the case, I certainly would want to pinpoint the location of the open circuit. Also, this sensor receives a 5-volt reference signal from the PCM which should be verified as well. Not a fan of repairing internal transmission harnesses.