Some good news about the 12v issue
Alright, y'all. So, I've been testing this theory about the AT&T 4G causing the battery drain for a week.
Just to give you guys a background, I got the vehicle two weeks ago. I only drove it for a full day on Sunday. The car was parked in the garage for 5 days. I tried to leave the house on Saturday morning but failed due to the battery drain. I panicked like most of y'all. Luckily, I have a NOCO jump starter handy and was able to start it right away.
So, I've gone into this sub and many other subs to try and find an answer. I stumbled upon one comment by one user that said he fixed it by turning off the 4G trial. I thought to myself, "hmm that seems silly but it may make sense because AT&T coverage may be terrible in my area." FYI, I use T-Mo and the coverage is amazing here. I called up AT&T the next morning and had it turned off. I left other DCM services enabled.
Just to make sure that I set the test correctly, I followed exactly how I left the vehicle the week prior. I did not move the car from the garage for 5 full days. I did, however, unlock the doors a couple times to see if the lights would turn on and the doors unlocked. In theory, this should also drain some more power. No issues with all of that. I haven't charged the car since Sunday either; it was left to 81% charged.
And here's the good news: I went to start the car this morning and it started! 🥳
With that said, this may work for me and a few others out there, but may not fix it for everyone. I think we still need to demand Toyota/Subaru to replace our 12v with an AGM or LiFePO4 version ASAP until they resolve the issue permanently.