Do I need a new big Battery?

Have you checked for recalls and prior maintenance history by running the VIN at http://toyota.com/owners

Please report here what has or hasn't been serviced since the car rolled off the lot.

If you are paying for a diagnostic inspection (or not depending on the dealership), they should offer with your repair quote a print out of the OBD2 scan with the DTCs that were reported. If those DTCs have associated INFs, you can also request such. Needed terminology might include, INF or "detailed code", and also known as "subcodes".

 

It would not surprise me if a 2009 with 132k miles had a failed HV battery. It's 10 years old and has a ton of miles on it. If this would be a California car, it may still be under the CARB 10 years/150k miles warranty

The good news is these cars last quite long and should get you to 200k miles with ease.

 

Thus far, failed HV batteries on 09 models have been exceedingly rare. However, rare does not mean impossible and you may have just gotten unlucky. Typically, MPG will go down and you’ll see more dramatic battery charge swings if the battery is dying. Since those did not happen for you, it’s possible that one module got out of sync

 

I'd call that, "We're not sure yet." That's not something you replace unless you are sure and there's no reason to not be sure. But, if it's actually under the CARB warranty and they want to replace it, go for it!!

 

Quite doubtful a mistake has been made, and the inverter pump repair will cost less than a new HV battery

The DIY fix could be in the $100 range, and some time spent wrenching.

There was a recall on the "inverter pump assembly", and your vehicle may or not be covered (is your VIN # listed?)

Per a previous suggestion posted above, did try entering the vehicle VIN at http://www.toyota.com/owners/web/pages/resources/recalls - to check which recalls (or dealer maintenance related visits) have already been preformed, if that is technically difficult for you, then ask the dealer if your vehicle qualifies for "Toyota 12V-536 (C0U)" or any other safety recalls.

 

OP is in Oregon not CA. Don’t know what the rule is for Oregon

 

I actually don't know which states follow the California CARB warranty, if Oregon is one of them, then the warranty would apply. But seeing we are at the tail end of 2019, I doubt it'll be under the 10 year mark.