it is possible you just have a dead sensor in one wheel. the batteries only last 4 years or so of normal use so that is the first and easiest possibility. I believe any tyre shop should be able to help diagnose a dead one and replace one that's a problem, the sensors are standard Baolong ones so anywhere should be able to get one that works. There is lots of info on this forum about it, so have a good search/read.
If it is not that, then it may be the antenna which collects the signals from all 4. these do fail (mine also did). You then have 2 options:
1. find a salvage antenna and swap it out yourself. there are a few around and when I checked they were $70 ish so not bad.
2. get Tesla to do the retrofit/upgrade to the newer Continental system. this will be $1200-1400 ish, but it is a better system and you will be able to see individual tyre pressure readouts on your dash (the old system just gives you a warning when one is low) so it's an improvement, but whether it's worth the money is your call.
Tesla won't repair your old system - it's policy to only offer the upgrade, so if you go for option #1, you'll have to go elsewhere.
I did #2, and I'm glad to have the pressure readouts but realistically it's difficult to justify the extra money, I was in a squeeze with my MOT (annual safety test, which non-functioning TPMS would cause to fail) due imminently and no time to source/fit a replacement antenna, so had to reluctantly go with the upgrade.
