2012 Prius V - lights, codes = Hybrid Battery Replacement?

First off, I've read a number of the threads about this issue.

I still am not sure what to do and would like a second or third opinion.

Vehicle:

2012 Prius V - 53,700 miles
Bought from original owner two months ago for $16,000
Carfax showed regular maintenance and no issues.
Took it to my local mechanic for a check - (no problems)

Roughly one month after buying it four warning lights came on.

Wife started it up in the morning to take it to work and got a 1/4 mile down the road when the lights came on. The heater and AC were not on and everything seemed normal.

The four lights that came on were:

Hybrid system
Check engine
Slip indicator
Brake System

After a few days, only the hybrid system light and the check engine lights were on.

Took it to the local Toyota dealer 15 miles away and it was driving fine. While driving it there the battery seemed stable and not going up and down quickly. Regenerative brake charging was working too.

They said it has the following codes:

p0a80
p3000

no codes in the braking system

They told me the hybrid battery was failing and it would cost $4000 to install a new one (12 mo warranty)


I've since disconnected the 12V battery and the codes went away and have not resurfaced in the following two weeks.

My questions:

1. Is it possible that the car just had a slight "hiccup" and nothing is actually wrong?
2. If the codes do surface again; should I replace with new or go with a refurbished unit?
3. Is there any Prius battery specialists near Hartford, CT that can look over the battery? Check the cells, figure out exactly how bad it is and what should be done.

I've contacted PriusKings near Hartford and didn't get a good vibe with them.

Thank you for all your help.
Brian in Tolland, CT

 

Pretend I don't know anything about mechanical or electronic on cars because I don't know a lot.

 

Thank you. Good article. I'll visually check the connections, but I don't have a voltage tester.

 

Update. I disconnected the 12 volt battery when the codes came up. Codes came up 2 or 3 times in total. Car wasn’t a daily driver before we bought it. Now that my wife has started driving it daily, the error codes have gone away and stayed away.