Long time Prius owner, new to using Priuschat: Code POA9B

Hello and thanks in advance for any help/suggestions. My first Prius, an 05 has 249K and performs pretty much flawlessly. My second, an 04 which I purchased in May, has 75K. While driving the 04 yesterday, all the lights came on the dash and really scared me. I immediately pulled off the road and checked belt, fluids and anything else I could. I then called the dealer and they thought since the car was running normal, to bring it in. For a hundred dollars I was told the HV battery, though working and not a problem, would have to be replaced due to a faulty "battery temp sensor" and that this part is not repairable....I need a new battery! For $3,800.00! Anyone who has had this problem, or knows about it, please help! Tomorrow I am taking the rear panel out and check the HV battery fan, etc. Can I drive the car with these lights on? Everything seems to work but the CC.

 

Thanks for info...live near Detroit, however. I think out of warranty (8 years in Michigan, even tho only 75K) Thanks again

 

Not sure where autobeyours is....will google. Thanks again.

 

Thank you!

I am looking all over the net and seem to see ECU for gen I, not II. Can I do this myself (pretty good with a wrench)? Any "how to" greatly appreciated. With only 75K I really want to keep my battery, if possible. Thanks again.