no more 3G on T-Mobile for ~2013 Audi...
 

Our 2013 Q7 came with 6 months free 3G data service from T-Mobile. I didn't value the service to the tune of $30/mo so I let the T-Mobile plan die. Eventually I turned on a Red Pocket, T-Mobile, data SIM for cheap entertainment. Worked fine @ 3G, just like the original T-Mobile SIM... a few months ago Red Pocket stopped using T-Mobile & sent me an ATT SIM. Worked OK, but only @ 2G. I read some stuff that suggested I would not get 3G with an ATT SIM in our car because of band frequency differences... I switched to US Mobile, who also uses T-Mobile. Still no 3G. I put the original SIM in, even with no service active it should at least show the available services... shows only 2G.

I talked to a knowledgeable service person @ dealer (at the suggestion of a T-Mobile tech). This is what I was told; When T-Mobile upgraded their infrastructure on the towers for 4G/LTE, they lost 3G on some frequencies, including those used by the 3G modem in our car. :( For those owners that have active Audi Connect service contracts w/T-Mobile, T-Mobile will pick up the tab for 4 hours of surgery on the dashboard to replace the 3G modem. I forgot to ask specifically, but I assume the replacement is still 3G max...

I might need to investigate tethering the car off my cell phone's LTE service as a long term alternative, especially if the replacement modem is still 3G, or just plod along with 2G. As long as one doesn't use the hotspot, the data usage is pretty low anyway.

If I'm missing something or am misinformed, please enlighten me.

There are several threads that discuss this. If you live in one of the affected areas, Audi wil cover the update of the modem at no charge which will include T-Mobile's new 3G frequency bands. BTW, these are the same 3G frequencies that AT&T uses and their sim will work after the update at 3G speeds.

I got the upgraded T Mobile Modem installed under the TSB when the letters came out maybe 2 or more years ago, when 5 G hits do you think there will be another problem?