Loss of battery range (really, not GOM issue)
 

I have a 2019 Prestige with about 7k miles. I have been driving EVs since 2014 (2014 and 2017 i3s (sold), currently a model 3 and a Leaf still in the family, we're an all-EV family since 2017), and I understand how the GOM and range estimation works.

My range has been pretty consistent, and as you can see based on my mileage, I don't drive a lot these days, usually a couple times a week for a few miles but that's about it, with the occasional longer trip. I charge to 80% and I usually plug in when I get below 25%. (Good battery maintenance practices all around.)

Last weekend when I charged up, my GOM only got to 90 miles at 80%. I don't pay that much attention usually when I charge if I'm going to be around town, but 90 seemed really low. So I busted out the app and my spreadsheets and looked at my history, efficiency, etc. and there's no way that's just driving efficiency (I'm at 43.5kWh/100mi over long term, and it doesn't vary much over the last two weeks--efficiency would have to be very bad to support that kind of range estimate in any case). My long term average translates to 218 miles of capacity based on a 95kW battery. Even if we're only accessing 88% of the full 95kW, I'm still well short of that, so clearly something's off.

I just charged it up again, and it tells me only 85 miles at 80%. So I'm thinking I lost a battery pack. I made an appointment with the dealer (it'll be a couple of weeks before I can get in and get a loaner). We'll see how it goes, battery is under warranty, so I'm expecting them to replace it.

I've been happy with the car so far, hope that they get this sorted out.

You'd think you'd be able to pull some codes if a battery pack is bad or you'd get a warning light on the dash. That sucks though. Hopefully its a quick fix!

This does sound like an issue with the BMS or one or more modules in the battery failed. The dealer will be able to tell you more.

Have you tried rebooting MMI to see if it resets GOM? I find it hard to believe that Audi’s first all-electric vehicle wouldn’t alert if a battery module went bad or offline.

It's almost certainly a dead cell or something with your BMS.

There is an off chance that you can fix this by depleting your battery to around 5% or so and then trickle charging it back to 100% to re-equalize the cell voltages. But since that IS the BMS' usual job, you will probably end up on the same place: i.e. having to get it serviced.

Can you get into the boost power range when you put the shifter into Sport? Often when a bank of cells dies, there will be a loss in available power as well.

When I put it in Sport mode, the green bar doesn't extend like it used to. My dealer appointment is on 9/2.

I have to agree. You've either lost a pack or the BMS has failed. Either way, it needs to be serviced.
Good luck.

So I posted a few days back...on a different thread. I lost 35% of my battery capacity about two weeks ago. The indications besides the loss in range were it only took 17.5 kwH of charging to replace 32% of the battery capacity, the power gauge on the virtual cockpit only went to about 90% (of course no boost indication). An an OBD11 code that I'm not remembering at the moment. I took it to the dealership a week ago they said it was a bad high voltage battery module (which I now understand to be a bad cell). They have all the parts to replace the bad cell, except for some kind of conductive paste which they don't when they will receive. They say changing the bad cell will only take half a day when they get the paste, which surprises me because I thought it was at least a two week job. Anyone have experience with a bad battery cell?

I started having this exact issue yesterday as well. 2019 Prestige with 9k miles. Battery indicates 80% charge, but range shows only 112 and immediately drops to 108 when I pull out of the garage....has consistently shown 155-165 @ 80% until now. Power is limited to ~85% and no boost available in S mode. Based on the comments so far, sounds like I'm heading to the dealer.....again.....(sigh). Interested to hear how the fix goes for others.

Finally have my E-tron back after being at the dealership for 3 weeks. Battery cell number 12 was dead. That limited the charging to 65%. One dead cell causes all the batteries to be limited so the voltage to each is balanced.