P0080 error. Needs new big battery per dealer

P3XXX codes are definitely HV battery problems. You might be better off with a rebuilt battery if you get one. There are companies scattered throughout the USA that do that work. Salvage batteries are another option. You can get them from various sources. Lot's of info online, search hybrid battery repair for more info.

 

If you want to do this yourself, use a digital multimeter to determine which of the 28 modules has a lower voltage vs. the rest. Each bank is composed of two modules.

Toyota considers it poor practice to just replace one module so its repair philosophy is to replace the entire traction battery. The concept is that if one module failed, the others aren't too far behind.

However if you wish to try replacing one module (assuming money is more important that your time) go ahead.

Yes, it is possible that a sensor wire connection might be loose and you can check that out once the battery enclosure is opened up.

Consult techinfo.toyota.com for repair manual info.

 

Wow, you had me pretty confused with those two pieces of information???

Anyway, yeah with your qualifications you should definitely be able to install the battery yourself. There's a really nice video here by member "3 prong paul" on how to remove the battery.

 

I am no expert, but the info I have read on the subject leads one to believe that are several items that can fail within the pack. Some repairs are made by replacement of modules, and rebalancing the entire pack. Others have had to repair sense wires. Others have had to replace and or clean the bus bars on the pack. Others have found a combination of the items I just listed.

I think once you get the pack out of the car and on a workbench that you with the skills you possess should be able to determine what needs to cleaned, repaired, and or replaced. It may be as simple as a sense wire, or it might be more complicated than that.

 

Get Mini VCI

 

Mini VCI from Amazon/eBay, $20-$30.

Techstream is the software made for Toyota, to read Toyota/Lexus/Scion codes. Techstream requires a proprietary OBD2 cable, called MongoosePro. This proprietary cable is available from DrewTechnologies for $495. Drew Technologies : Introduction

Since you really don't want to pay $495 for this proprietary cable, buy a knock off called "mini VCI" from Amazon/eBay for $20-$30. These knock offs will come with hacked copy of Techstream software. You can always find the latest version of Techstream somewhere; version 8.0 is sufficient to work on your Gen2 Prius.

For your safety, just assume the software has viruses, malware, etc, reporting your every keystroke back to a criminal organization. People who have installed this on their laptop report their anti-virus program going crazy. Thus the use of a spare laptop that will only be used for Toyota diagnosis, and never used to log onto the Internet with confidential info (email, banking, etc). That being said, many here have been using hacked Techstream and mini VCI w/o any issues.

There are lots of sites that have Techstream installation suggestion and trouble shooting.
This is a good place to start for Techstream guidance: TundraTalk.net - Toyota Tundra Discussion Forum - View Single Post - Offical TechStream software thread( settings and such)