Help With Next Move: Code P0AA6 and Subcode 612

Hi Everyone, Long time lurker, but first time poster. Prius chat has helped me alot along the way and I am thankful for that. This is my first real deal issue with my 2009 Toyota Prius. I've have it about 6 years, total mileage at 220k, 100k of that is me. It's a great vehicle and has ran well with routine maintenance.

I threw red triangle, yellow exclamation, and VSC while on way to Home Depot a few day ago. Turned it off and the vehicle locked down and wouldnt let me start. Pulled the 12v aux plug in back and it let me get home. I ordered a MiniVNC TechStream from Amazon, which has been awesome and is a MUST for a Toyota owner IMHO. Amazon search "Yueku Mini VCI J2534 Toyota TIS Techstream Cable Car OBD2 Diangostic Cable (1.4.1)"

Anyway, I am seeing Code P0AA6 and Subcode 612 (attached) P0AA6 is a Hybrid Battery Voltage System Isolation Fault, and according to another thread I'd encountered the subcodes represent: 611 = AC compressor, 612 = Battery case, 613 = MG1 or MG2, 614 = inverter or DC cables, and 655 = MGR. I thought this was awesome because I really didnt want to see 613.

So my next step was to do a ground test on the pack. I followed this video, which is kind of neat and turned out accurate: Youtube search "Gen 2 Prius P0AA6 battery leak confirmation" Sure enough my meter showed a consistent voltage of 30.8V, which confirmed my leak was in the pack.

I next removed the safety plug, removed interior, and removed battery shield to find a pretty big and messing electrolyte leak in the bottom of the battery case. Bingo! (attached) My research gets alittle fuzzy now at this point.. What is my next best course of action? Any replied appreciated. Thank you!

 

Going to brake down the battery pack and begin to look for leaky cell(s). Will update the thread as I proceed. Thanks a lot.

 

Thanks Strawbrad, yes this all makes good sense. Ive opted today to take it to a guy I've met who rebuilds/conditions HV batteries. I know I could do it and for less money but I think I am going to throw this job to him this round. If I get another failure within the year I plan to start doing it myself. He said he can get me back on the road for a few hundred bucks so I am going to let him take it. I give it to him this Thursday 11/1/18. I will document findings, area, price of fix, and location for the forum. Thanks for the above tips.

 

Found a new guy who's agreed to take a look. Dropped it off today. Seems like a nice guy, curious to hear how many cells are not good.

 

So the shop just got back with me and is saying that he could not find a leak in any modules and modules have all been discharged and recharged and balanced. He doesnt think it's a bad modules. Hes theorizing it could be a bad relay or bad battery controller ECU. Ive asked him to button the car back up and I am going to get it again tomorrow. I asked him about the level of corrosion. He said it appeared as older build up and average spillage due to the vehicles use. He was not able to find a ground fault. Thoughts on this? I guess the plot thicken...?

 

Well turns out the people I took the car to are total dumbasses and don't know what they are doing. I got bad vibes from the moment I left the vehicle. He claims to have tested the modules, discharged, recharged and balanced and everything is good, then claimed it was the inverter, then the mg1 and mg 2 generator, then mumbles something about replacing the battery ECU, just totally random crap. I tell him not to do anything and Im coming to get the vehicle.. I get there and the vehicle hasnt moved and the battery case hasnt even been opened.. I know this because I rigged the case with a piece of masking tape and also all the cover panel bolts I selected and left in were exactly the same. I had to buy my key back for a couple hundred bucks before I could get the prius out of there.. Total con artist idiots. Anyone who may come across this thread in future in Fort Myers Florida area needs to avoid these people:

Buy Rite Auto Inc
Hybrid Battery Repair
8236 Engle Pl #2
N Ft Myers Fl 33903
(239) 826-9097

Total conartist idiot. AVOID!

At this point I've decided to reset the code each time I drive it to work, which I am doing 9 miles a day total. I am going to risk it and just drive it because the vehicle is not worth much at this point anyway. When I get time Im going to order ebay modules, break down the pack, clean and start replacing based on observation and position of leak. Ive been without a car 3 weeks and I am just over this process. Will update forum in time to see how it does driving on a leaky module! Woohoo!

Cheers

 

Will do. Luckily my wife has been taking me to work in the 4Runner (SR3). This Prius was originally her driver when she had s big daily commute years ago (160 miles daily). I've had the car since our first child was born and we put him in the SUV. New pack would be cool but I just don't think I am willing to sink 2k in the car. I just watched a 2009 Prius with 148k miles sale from 3,500 on Facebook Market and I am looking at a 2016 RAV4 with 33k miles for 15k (non hybrid) which I'm going to eventually do I think. I talked to these folks last night, they are in Sarasota Florida and can do a resused pack that according to them has been "rigorously tested". For 700 installed with 6 month warranty. eBay

I may do that before I trade the car towards the RAV4. (Private dealer). I am just going to keep driving another few weeks and think about it.

 

My tech stream is showing good voltage and not terrible resistance in the modules. I fill probably get bored one night and just fix the leaker especially if I'm going to trade it towards a gas burner, I've just gotta get the time to pull it apart. Maybe if I keep driving the module will die completely and make it easier to find when I jerk it apart again. Oh well! About to head to work in her. I installed a JIS terminal switch on my ground so I am just flipping my ground off and on before driving. Quicker than clearing. Ha! I know.. I'm a bad boy!! But hey I'm going to keep running her, she's a work horse.. always has been. Cheers

 

Hey Johnson,
I still havent broke the pack open again. I wish I would have fixed it when it was all broken down but was intimidated at the time. I installed a reset switch on my aux ground and basically reset the car when I throw the fault. I dont drive far to work everyday 5.5 miles round trip so the car has been running the same. Installed a Switch to Keep Driving | PriusChat

Ive got some off time coming up and plan on breaking it down to find the fault. I was hoping Id have the block fail so Id know for sure in Techstream what block was bad but no dice. Just ran techstream again today on it and all my voltage and resistances are still the same.

I will document everything when I do it for other sake.

Hope its worked out for you.

 

Hey Brad Im attaching my driving and off HV battery voltage and resistance that doesnt tell me anything about what block or how many blocks are bad does it? Do i need to order modules from you after I get in there and visualize for the leaker? will a volt meter tell me? Does it need to be under load?

Also,
Do I absolutely have to balance the pack? I was curious if I could attempt to volt match alittle and just put it back together. Getting ready to break the pack down soon and doing some planning....

Thank you!!!!!!!!!!!!!

 

Yes I ended up replacing the bad module. It was a leaker and the pack was filthy inside. I've moved my work over to this thread:

Installed a Switch to Keep Driving | Page 3 | PriusChat

 

reporting in 5/9/20. I've put 10,000 miles on the 6 modules switch with no rebalance, no errors. still driving.

 

Just received a new Red Triangle on 11/3/2020 made it to 233k miles. New thread created:
My 2nd P0AA6-526 Hybrid Battery System Isolation Fault on Original Battery | PriusChat