does P0AA6 with 526 and 612 sub codes point to the HV battery being the issue 100%?

As you see in this drawing, 612 refers to any of the stuff on the internal-to-the-battery side of the system main relays.



A person who wanted to avoid unnecessary work would probably open up the battery case and inspect to find the cause.

Simply replacing the battery will probably fix the issue ... except, if the replacement battery is from Toyota, I believe it omits certain parts, which are to be swapped over from the old battery. If one of those parts was responsible for the code, then that would be a disappointing outcome.

 

No, with this trouble code it's not module voltages you're after, but current leakage paths to the metal chassis from somewhere among the components shown in the 612 area of that drawing.

If you look up the troubleshooting steps for P0AA6-612 in the repair manual, you'll see a sequence of steps involving disconnecting the internal cables from the system main relays so you can megohmmeter-test those in isolation, and the internal cables, and the battery ECU, before concluding the problem is in the stack of modules.

A megohmmeter is a specialized instrument and its use presents hazards. If you don't have one, and you think about buying one, you can search for threads here that will refer you to safety info you should study while waiting for the tool to arrive.

Sometimes, if only one leakage path has formed, you can get usable information by comparing voltage measurements from both ends of the pack to chassis ground. If you see an intermediate voltage, it nearly tells you where in the stack of modules the leak is.

But that only works if there's only one leakage path. With more than one, you will also see some intermediate voltage, but it will just be the voltage of the Thévenin-equivalent circuit made from all the modules, the leakage-path resistances, and your meter's impedance, and that won't have an easy interpretation in terms of where the leaks are.

 

When all this mess started in my '09 played with it a few minutes. And order the brand new battery from the dealer as mine was from '09 old is all get out use my front end off my battery computer and all that. Bolted it in never saw another light again till the brakes went out fix that now no lights just the PO420 can't nobody make that go away there's nothing in the path to replace.

 

I pretty much had the same exact code you do if I'm not mistaken and I did put the battery in myself and I did strip the battery down in my trunk as my core that you have to drop off when you pick up your new battery so I had another battery in the 2005 that was shot I took that out took the front end off the battery had it sitting in the trunk on top of the battery that was failing that's in my '09 drove all the way with the ice engine running at 36 mi to the gallon the Apex North Carolina where they handed me a new battery out of this big box that looks like it was refrigerated it was so protected but it wasn't refrigerated it was the thick box I set my core in that and took what was in that box and heaved it in my trunk. Went home added my front end which is the computer and the relays to the case that I just bought from the dealer and then drop that on the mounts and flip the switch and that was pretty much it I have mine mounts trimmed and cutting the funny way so that makes it so I can move the battery out of there in about six or eight minutes now

 

If replacing the battery made it go away, it was the same code. (At least, as long as we're talking about P0AA6 codes with some subcode.)

Notice that's the converse of "if you have the same code, replacing the battery will make it go away", and a statement doesn't logically imply its converse.

 

I had the p0AA6 code And after fiddle farting around on here getting all the sub codes in the snowflakes and the whatever I just decided to pull the battery pull the cover off while it's sitting in the hole and saw the disaster It looked like it had been played with before had bunches of writings on tops of different modules and what have you I knew somebody had done the dance before and wanted to just be rid of the nonsense. So I bought a new battery above is stated drop that in didn't even clear any codes just started the car with the battery and the metal case bolted down in the back just sitting there no trim back in yet nothing not doing that stuff three four times. I drove the car about 4 days with that trim removed so I could look and see everything add some leads for my Venice hybrid 300 volt charger and what have you. Then it went all back together I haven't even topped off charge that battery done anything since I put it in. A very interesting aside and something to note is the first 90 days of the new battery being in the car I never saw green on the MFD I also didn't see the magenta color either after 90 days I started seeing green almost daily and on almost every trip I make but I thought it was interesting about the first 90 to 120 days never saw green on the display and believe me I was looking at everything for those 90 to 120 days.

 

I initially had the 526 with the 611 sub codes now that's turned into 612 and the 611 is gone maybe I had the 611 because my air conditioning was unplugged? I've pulled the battery that was a replacement that was built from a guy uptown turned it sideways and I'm looking in the bottom of the case which has been painted beautifully before reassembly between the bottoms of the battery modules and the case the case is perfectly finished painted inside not a scratch not a drip on it anywhere not even on the ledges I'm looking through the case with an extremely bright flashlight I've also run a very light steamed towelette across the bottom of the case and pulled it out smelled it touched it with my tongue and there's no battery acid twang or anything like that. So now I'm thinking just swap out the HV battery computer The relay seem to work they're off when they're off but I'm not sure what voltage is I'm looking for with the plug in I have 124 volts on one relay and 94 5 volts on the other anyway lots of fun I reset the mess car drives a little while and just all of a sudden randomly doing not anything specific the red triangle comes on I continue to drive to wherever I'm going and when I get there all I need is my cheap scanner tech will not reset this It won't get me to ready The only thing that does is my cheap and over scanner clearing the code which aren't existent to this scanner I clear the codes twice restart the car and off we go.

 

From those points to where? To chassis ground? The voltage you're looking for is zero: the HV system is intended to be completely isolated from chassis ground at both ends. That's what the P0AA6 code is meant to check for.

A little bit depends on what the impedance of your voltmeter is. If it's high enough, you could start reading voltages there even from just the tiny amount of leakage in a car without a problem. You could parallel your meter with a resistor to see how much difference that makes; using the value of the resistor you used, that could tell you something about the impedance of the leakage path.

If there is only one leakage path, it'll be in the neighborhood of 94.5/(94.5 + 124) of the way from the end of the pack showing the lower voltage. 94.4/218.5✕28 is about 12, so around the twelfth module counting from the lower-voltage end.

But (repeating a little from the post you quoted) that math only works if there is only exactly one leakage path present. If there's more than one, then what you're measuring is a Thévenin-equivalent voltage and you need to know the impedance of your meter pretty precisely, and the math isn't easy anymore.

 

Yeah I measuring these voltages to the battery chassis so on one orange wire going to the main relay is 124 volts and the other one is 94 or something like that and 56 volts on the bottom bolt of the orange plug again to the battery chassis which I'm assuming is ground I'm just trying to quickly check to see if those voltages are okay for the battery to be working with I guess I could open up my other car and measure the same way and see if I'm close I just saw further up in this post where the guy said he measured 40 volts on the orange plug bolt doing that test and he said he knew immediately something was wrong so I'm not sure if that voltage is too low or if something else is up. Mine's a steady 56 volt reading orange plug inserted fuse cover cap off me measuring on the bottom silver bolt to the battery chassis. The battery internals and the tray everything is whistle clean I can't imagine where this leak can be happening I don't see battery fluid remnants none of that this thing was just put together 3 weeks ago or so The battery that is.

 

And you might have noticed I've gone from the air conditioning 611 sub code is that right now it's the 6:12 sub code for the battery pack that's why I'm back in the battery looking In the air conditioning circuit everything was clear looked great that doesn't mean anything but. With it disconnected the air conditioner from the inverter plug it still coated and triangle so that wasn't even connected a few code set a go.

 

The funny thing is I'll try to take some pictures I should be able to get very nice ones they just won't post and look nice I don't see any leakage to the tray of the case that was just assembled painted so on and so forth like 3 weeks ago I have the battery slid around sitting at an angle and I can look right down the whole tray it's beautiful not a scratch on it not any liquid that I can see anywhere My battery guy says he knows it's not leaking He said there's a direct leak somewhere or voltage going to something and I'm like you got to be kidding me. But it's giving me the battery area code prior to this it had given me the inverter air conditioner area code but that may have been because the air conditioner was unplugged from the inverter? I'll have to go out reconnect everything and see. One thing I did notice when I was cleaning the plug the orange one for the HV battery computer my finger got to tingling while I was cleaning that plug I could feel voltage going through me I guess so because that plug monitors the HV battery and the HV system I guess once I move my finger from the plug I can touch the battery all around standing there and don't have this feeling at any of the modules everything is whistle clean I have pictures most of the modules are the post seem to have seemingly consistent voltage nothing jumps out at me from looking at other videos and looking at my '09 which is essentially running perfectly that's the car that has the new battery well now it's about a year now I'm going to set the battery chassis on two long rubber strips like you used to mount a pickup camper on a truck bed set the battery on those two strips so the battery is not touching the metal frame of the car temporarily and see what happens with the battery semi isolated not bolted down with metal bolts so on and so forth I can get plastic bolts to mount the battery down if I want to keep it isolated Not sure what that's going to do but I just don't think battery is leaking to the frame of the vehicle via any direct copper or liquid from the battery at least nobody can see it. And the last two batteries I took down you could see the liquid where it had run out it was very clear to see it was a whitish color look like regular battery acid when it dries and tasted the same there is none of this going on in the vehicle I'm working on right now none of it.

 

The car's ECU, programmed to monitor for electrical leaks, is telling you there's an electrical leak.

Your multimeter, in seeing a voltage between the battery connections and chassis, when that's supposed to be isolated, is telling you there's an electrical leak.

Shouldn't be confused with a visible leak of the electrolyte goo. A goo leak can be one common reason for an electrical leak, but strictly speaking, the ECU is only monitoring for electrical leaks, not goo leaks.

Who ya gonna believe, the chorus of instruments, or your own eyes?

 

I'm so like I said before the battery is bad and needs to be replaced just that simple like I thought chasing down an electrical leak inside of the battery well seems to be kind of pointless. My meter doesn't seem to indicate that battery is voltage is leaking somewhere seems to be pretty steady on both sides of the of the terminals Why one has 94 in the other one has 124 I have no idea they're not the same amount of sales connected to each thing right I mean now I'm going to go have to open the mess up on my running car to make the voltage measurements and when I get the same measurements I'm going to be well looking at this like what the hell The gold car is not being driven today so in a few minutes I'll be out with the test meter to test both sides of the relay to see what I actually have and from the metal screw at the fuse to the frame. I'm not discounting anything I don't have another spare battery here to throw in the car That's all. And then I think it's funny that the battery I removed from the car which was the original had this issue and then the new battery that the kid built has this issue 25 hours after the fact I just think that's kind of neat It doesn't seem like it's leaking away at the battery but okay. I mean the relays are off and they're off they don't seem to be leaking anywhere so we're saying an individual module is causing all this sounds good to me. I'll go back and look at some videos and see what my measurements should be across the two relays and from the bottom of the fused plug for safety and the chassis ground I thought that test was looking for voltage to be going up or down the scale rapidly not steady holding it some voltage that indicates nothing's leaking seems to me. Seems to me with the voltage running up and down your scale on your meter that would indicate something wild and not in control. But I don't know much about that. And then it seems awfully odd the car drives for hours with no code and then just turning into the driveway it codes. And why can't tech clear the code and restore the car to driving I have to unplug tech and plug in a $39 scanner from Walmart clear the codes that aren't on the display twice and the car boots without issue and not without instance and drives all day Nice setup pretty cool.

 

So then it's a rebuilt battery issue or battery issue need to get it out of there get a new one and that's done.? Without a bare wire touching the chassis copper metal something or goo or is delete going to come from?. And it's got to be an HV leak so that means the 211 volts is crossing over.?

 

Well I am looking on some sites that you probably frequent or have looked on many times before or maybe even have contributed to and they are showing mushroom things or the bus bars are adhered to the battery with the nuts all kinds of things I have none of this going on I also don't see any wires damaged and the only time I feel this tingling sensation business going on is when I'm messing with the orange plug that's on the battery I have it hanging over the edge of the case and I'm cleaning it with stuff like battery terminal cleaner when I'm not doing that there is no voltage felt in me or whatever.

 

The fact that you can measure any volts at all there, between either of those terminals and the body ground that is supposed to be isolated from both, is the crux of the issue.

 

Disconnect the hybrid battery orange cable from the back of the inverter and test it for a leak to the ground. I've had a bad hybrid battery cable on 2 priuses so far.