Not being able to change ID address or communicate with TIU has nothing to do with the DCS transmit and receive chips that communicate with the engine. Sounds like some other fault, and that may not be repairable.
If a TIU can transmit the watchdog. The transmit chips are probably fine. If you can not load an engine or receive a DCS signal strength response from an engine already loaded, that could be receiver chip. For example an engine loaded can be started. But can't respond when necessary. Transmit fine, receive not. Being able to load an engine requires a transmit signal, and the receive signal from the engine. G
