P0A80 Check Hybrid System... Wiring Harness???

OK PriusChat peeps. Y'all are awesome, so I need some guidance here.

I have a 2010 Prius with about 135k miles. I started getting P0A80 codes about a year ago. I didn't act right away, because it would go away for months at a time. I have not gotten any other codes at any point.

Now, it comes up every 100 miles. Here's what I have done so far and the results:

1) Took it to the Toyota dealer with the codes reset. They couldn't find anything wrong at that time.
2) Took it to the Toyota dealer with the P0A80 code active. Their only remedy was to replace the entire HV battery for $3900.
3) Disassembled the battery and cleaned the copper bus bar plates with vinegar and steel wool. No code for about 4 weeks.
4) Disassembled and tested cells with multimeter only. No clear standouts in voltage drop, even after sitting for 1 week. Replace copper bus bars with anti-corrosion nickel plated bus bars from GreenTec Auto. No code for ~2 weeks.
5) Disassemble and tested cells with multimeter and headlight bulb (12v 55W 4.5A). No significant voltage drop with 120 seconds of load (.15v min, .3v max, no big outliers).
6) Full reconditioning process with Hybrid Automotive Deluxe Reconditioning Package. Started with the 2 cycles, most recently ran 3 cycles. Diminishing returns with each cycle. First time, no code for 2 weeks, most recently, only lasted 100 miles.

My ICE is running a bit rougher than it has in the past, and there is a very noticeable hesitation when it kicks in now, almost like the car it going to stall. I'm behind on replacing the spark plugs. Don't know if this is related but thought I would mention it. In fact, now that I write this, I'm gonna just order new plugs and install them now. I figure that's $20 in parts that can't hurt.

The only thing left that I can think of is to replace the bus bars completely, but that is a $150 fix for something that may not be the problem. Given my testing, I feel strongly that the battery is okay, so I hesitate to drop $2-3k to just replace it.

I've called several shops (Hybrid, Electron) for help over the phone, but obviously they can only do so much remotely.

Can anyone think of something else I haven't tried/tested yet?

Or, does anyone know a shop in or around Orlando that I can take the battery pack to for further testing? I'm really good at removing it at this point

Thanks in advance! This forum has saved me thousands of dollars so far!

PS - if anyone wants a good deal on the Hybrid Automotive Deluxe Reconditioning Package, PM me. I may have one for sale soon!

 

Just removed the harness to test individual modules. I haven't checked the baseplate, so that's a good next step.

 

OK, I've completely disassembled the battery and removed the individual modules. There is quite a bit of new corrosion on the wiring harness, even after I installed the anti-corrosion bus bars.

There's no clear signs of leaking on any of the modules, but I may not know what I'm looking for. The baseplate has spots and corrosion dust all over it. I see two spots in the middle of the baseplate. I took some photos, can y'all see anything that I'm missing?

 

Thanks, Eric!

Any suggestions for a good iOS app? All my devices are Apple.

My local Toyota wants $2800 for just the battery after core charge, and $1000 to install it. Plus, no warranty if I install it myself.

 

So, follow up here. I checked everything and it seemed fine. I finally found an iOS app (Dr. Prius) that could give me real-time readings on the cell voltages. Everything ran green until I started driving, then the voltage dropped too low. I ran the Life Expectancy test and it said less than 37% life left, time to replace.

So I sucked it up and bought the new cell kit from NewPriusBatteries. Install took a day and I'm back up and running.

I have all my old cells, wiring harness, and vent tubes. @ericbecky, do you know if anyone is buying hybrid battery parts here? What's the typical value?

 

8 month follow up: I'm over 2,000 miles into the new battery from NewPriusBatteries, and I couldn't be happier. Prius is running like a champ and I'm getting 44 to 47 mpg. My only regret is taking sooooo long to decide to replace my battery. If you are getting the triangle of death, get an app like Dr. Prius to test your life expectancy, and use NewPriusBatteries to buy a replacement if recommended. 1600 bucks and I was back on the road. This was less than half the price for a used battery from the dealer.