P0AA6, 526, and 612 with +B 11.79V can this be the Aux battery

Your 612 is the detail code I believe that you're interested in doesn't that put you back in the battery case in the back the HV battery not the 12 volt this is not the hybrid isolation fault? And that detail code I thought put you in the battery case in the back of the car not the cables running to the inverter or the inverter converter itself or the AC if I'm not mistaken so if that code is active that puts you back looking for more leaks so it seems like you've got modules that are at their limit and when they get heat looks like they're discharging more than they should or whatever. You haven't noticed your fan running or anything like that? Interesting it's getting about that time of the year most places

 

Code P0AA6 indicates a high-voltage circuit current leak. The 12V battery has nothing to do with it. Check this message. You have problems in the high-voltage battery area again (subcode 612)
P0AA6, detail 526, and 612 | Page 2 | PriusChat

 

It is a hybrid vehicle (HV) battery fault for sure (INF 612), so yes, you will need to open the HV battery again. While the 11.79 V shown for B+ is not great (at a minimum, that 12 V battery needs a full charge), it is above the 10.5 V threshold the RM uses as the tipping point. Even so, I would fully charge that 12 V battery while working on the car.

It is the same issue. A physical leak of electrolyte is not what is meant by leak in the context of P0AA6-612, although, if present, it contributes to the electrical voltage leak (to chassis ground).

When you replaced the leaking module previously, did you thoroughly clean the battery case of all leaked electrolyte? If not, this could be your problem. Or, you have another module that is leaking. Replace all leaking modules and thoroughly clean the case to remove all traces of electrolyte before reassembling the battery.


[EDIT] MAX2 beat me to it, LOL.

 

It's usually one of those 56 little tiny screws that hold the modules to the tray base all you need to do is put your test meter to ground and run the positive lead across each one of those little machine screws and each one where you get a reading mark it with a red sharpie they need to be dealt with whether you put a dash of goop where the little screw was supposed to go or change the module whatever something has to be done about that screw hole. And then usually in the middle of the pack where all the heat is happening that's where the prismatic modules tend to leak the most in the middle hence you see all the traces of the white stuff mid pack generally

 

I'm talking about the 56 little machine screws that hold the modules to the base plate when they're racked together all assembled ready to go doesn't really have much to do with the bus bars but to unrack everything generally you take all the bus bars and nuts loose but to check this real quick you don't really have to do that you could just flip the battery assembly on its side and measure from ground to each one of those 56 screws anything that lights up the test meter gets a red mark that means the screw is going through the plastic and the electrolyte is getting to the tip of the screw thread and of course getting to the case of the battery because the screw is going through the case and into the module many times after rebuilding you'll see a bunch of those screws missing been left out on purpose this is probably why

 

When cleaning up electrolyte in general, any battery that doesn't have toxic components (that is, not lead acid or NiCd, those need other steps) wear gloves and use a water dampened cloth, paper towels, even a sponge to remove all the chemicals. Treat it like a liquid spill even if it has dried. Afterwards, wipe the surface dry and wait. If no crust or "dried stuff" mark forms then it is clean.

Don't use a wire brush on dried electrolyte because that will throw specks of it up in the air and it might end up in your eyes or lungs.

If the electrolyte caused rust that must be addressed do so after removing all the spilled/dried electrolyte.

Unplug the battery or batteries involved first!

 

Toyota's docs have suggested using a boric acid solution when cleaning up the NiMH batteries. It will help neutralize the highly alkaline electrolyte.