Had a feeling this would happen but I guess I like learning the hard way. Went to Toyota with a P0AA6-613 sub-code, was told it would be $170 or so to diagnose said code. Asked specifically if that was just to read the code, and they specified no, that is to diagnose. They then call me 3 hours later telling me it could be all sorts of things and that they need to test the battery, all the hybrid components, etc, quoting 10 hours of labor, I then tell them I just want to 4 problem areas related to the transaxle tested, and they quote 6 hours of labor for over 800 bucks. I informed them they said it was $170 and they said that was just to pull the code. Avoid these crooks at all costs.
I had the transaxle oil changed at the dealer so doubt they put the wrong stuff in, but at this point I wouldn't be surprised. I guess it's possible changing the oil made things worse, as I hadn't change it since I owned the thing and put at least 50k on it at that point, and have no idea the last time it was changed if ever, in the 200k+ before that.
You can call Toyota customer service and complain. It often works because Toyota, unlike US brands, is a quality focused company and they value their reputation greatly. They will listen to your complaints and then ding the dealer who will often make amends with you rather than getting black marks on its internal record. Much more effective than complaining on social media.
I own many Toyota cars and I often visit the dealer. I never know what to expect, either I get my service request done properly or not. My last service with my 2019 Rav4, just before the warranty expired, I noticed a leaking rear shock. It wasn't a massive leak, but still you can tell the shock was wet. Took it in and get a call later telling me there is no leak, I told them I wouldn't be wasting my time if there wasn't a leak there. Sent me pictures of the shock and it was wiped clean before the picture. I was like Wth, I know I didn't clean the shock before bringing it in. They told me the tech cleaned it so he can get a better picture. So that just tells you there is something wrong with the dealerships.
I've had the wrong fluid in my gen 2 transaxle. For over 2 years now. It's still nice and red and everything is fine I never knew there was a code or a code related to possible transaxle fluid failure I do know from what I understand they change the fluid in the transaxle and the hybrid cars because of all the electrical things going on in the transmission. And that's wonderful I'm running generic import CVT oil I think it's from Castro it might even be synthetic I don't know. It's worked well and none of my codes are related to anything with my hybrid system or transaxle I wish it were that simple
Especially that specific dealer. Or at least the service rep. Might want to call them out publicly so other people can avoid them. May just be a California dealer thing. If the problem is documented by you on the service invoice and reoccurs within a month or two even after warranty expires, it will be replaced under warranty.