@Alex800st
Ok, hold on. Your dealer experience has been bothering me. I really don't think this is the case, couldn't be, however I really hope they were not trying to update the software on your "
non-existent Transmission Control Unit" (TCU).... I doubt it, but man we have heard of some bone head things dealers do around these cars. They often cannot even spell PHEV yet...
However, the above aside, I wanted to test this, and then give you something to try. You can bypass the Cellular communication route side of the TCU (sorta) with HondaLink and test and see if your car can communicate with your app correctly first (or after your re-bind). You have to give your car a way to access the internet. It CANNOT be through your phone that you are using to HondaLink with (and bluetooth must be off on your hondalink phone).
So, if you have WIFI at your house where you park you can use that, or another non-hondalink phone as a hotspot. You need to set your Infotainment system to connect to an available hotspot with internet. You need to confirm it is working but making sure it is not using hondalink through your phone (turn your phone off) first. So connect it to wifi, then use the hondalink on the infotainment system to do something that requires internet (hondalink weather, places search, use the web browser, internet radio, etc.) whatever to make sure that your car is online through wifi. You can then turn your phone on and connect to the same WiFi (again your car cannot be connected to your hondalink phone as a wifi hotspot) so you are on the same network.
See if you can perform Hondalink functions from your phone then (turn it back on, bluetooth off, put it in airplane mode but turn wifi on and connect to your house or that common hotspot your car is on). If it works, then turn your phones cell connection back on, and it's wifi connection off. Then try again (this lets you know if your car can still communicate via the wifi, and that your phone's hondalink still works over your cell data connection.
The car connection will try to use the internet wifi hotspot first (you should not have to have your car on, it should be listening through wifi). If it can talk to Honda's servers through WiFi it generally does not bother using the 3G. So, that would let you know if it is the 3G connection through the TCU or if it is your actual HondaLink server connection in general (Honda's hosted servers and the way your car is registered with them).
Sorry if that was confusing, but hopefully you got the idea. Kind of like how your phone will "prefer" to use a WiFi hotspot internet connection over the 4G cellular internet if the WiFi is available and on. Your car always has a passive internet connection to any hotspot it has been allowed to connect to in range.
Let me know if this has any diagnostic value for you. I am sorry it is a long post, should have made it a step by step. I'm tired and wanted to get this to you before I called it a night.
Good luck,
Cash