I think Gruber and Wk057 repair packs/have repaired them successfully, and I think both offer full warranties on their repairs of packs?
We do NOT repair modules or cell level issues. This is NOT possible on Tesla battery packs (except for the Roadster), despite claims by other people/companies/popular YouTubers. Do not fall for that nonsense. You'll get stranded just like the rest of the folks who've attempted this.
I get a few contacts per day at this point from people with battery issues, and thanks to the misinformation spread by folks claiming these magic BS "We know how to do it and they don't" type "repairs" like cutting a fuse or swapping a couple of modules, we have to explain the truth to them (with various types of reactions to this information).
I have an example customer who originally went to one of these companies, that's been named many times before, for a battery "repair" ... after driving for 2 months their car completely shutdown out of no where. They contacted that company, who claimed something else must be the problem and they'd have to pay for
another "repair". Instead, they contacted us, didn't tell us anything about this original "repair" they had done, we get the car, inspect it, and it's immediately obvious what the issue is. Physical damage to several modules (removed cell fuses) causing an SoC imbalance that the BMS wasn't designed for and is incapable of handling long term. We told the customer what the issue was, and that they'd need a pack replacement... and noted it was odd that the fuses were completely gone, not blown, and that the pack had been opened and (poorly) resealed previously. They finally told us about the original "repair" done by this other company. We managed to get the back up and running with a full pack replacement for around $4k net cost, since the non-butchered modules in the original pack were perfectly fine and cost-recoverable.
The customer later wrote a lengthy hand-written thank you letter to us, which noted a few things: We were able to do a real repair (full pack replacement) for less than they paid this other company to do a fake repair that damaged their battery pack, and as a result of the whole ordeal they were working on a lawsuit against this other company for the damages and false claims.
So... yeah, don't end up like him.
Now, there are certain types of repairs that are possible to the pack (replacing BMS, cell sense leads, BMBs, contactors, etc etc), but when the issue is with cells within a module, cell fuses, or similar things... then the
only real solution is to replace the entire pack.
You can't mix modules in a pack they didn't originate from.
You can't cut fuses on cells and expect things to work properly.
The people who have done them are well aware they don't work as real fixes, but they leave these garbage claims up for clicks, likes, and views. Nothing more.
There are very real reasons that Tesla doesn't do these fake repairs themselves, and it's not because they couldn't do them. It's because they don't work and aren't actually a repair. Sure, you might make it seem like the car is functional again after such a hack for a little while, but you don't
actually have a fully functional pack anymore. Instead, you're continuously gambling with a pack that could just shutdown at any moment with or without warning.
If a module is bad, you must replace the pack as a whole. I really wish people would get this message and it sink in.