I put the engine and tender on rollers on a test track connected to a Lionel transformer. This is with the entire layout, including Legacy base, turned off. On increasing transformer power, the loco starts up in conventional mode. I tried turning on track power both before and after starting the LC app on my iPhone. Still, the app says "no connected locomotive". There is a definite reaction from the engine while trying to connect, so I think that some form of Bluetooth is there.
Does this qualify as a good test? For the LC app to be able to identify a particular locomotive, it must read data stored in the engine. Is that correct?
Another possibility could be some type of interference. We have several other things in the house that work by Bluetooth. I tried turning these off with no effect.