P0AA6 explanation

If you still see the option to edit the title of your post, you should change the title to say P0AA6 and not P00A6.

There is a high-voltage electrical system that runs through the car, from the battery in the back to the inverter and transaxle and air conditioner in the front. The cables in the high-voltage system are all orange to distinguish them from the regular twelve-volt wiring.

For safety, the high-voltage system is built to be completely isolated from the twelve-volt system and from the body of the car. Yours is not. The car regularly self-tests for isolation failure in the high-voltage system, and gives you the P0AA6 code if detected.

Changing the battery is the solution only if the electrical leak is inside the battery. If it is somewhere else in the car, changing the battery won't fix it. Along with the P0AA6 code, the car will be giving a three-digit "INF" code, 611 through 614, that is more specific about where to look for the leak:



Just clearing the code and driving around with a high-voltage system that is conductive to the rest of the car isn't a very good idea. The existence of one extra conductive path usually doesn't hurt the car though. If the car is old enough to have had one such path develop, though, it might just be a matter of time until a second such path happens to form. That's enough to complete a circuit.

 

The code means basically that high voltage battery juice which is around $211 volts is reaching the frame of the car and trying to intermingle with the 12 volt for instance. The way I understand it is if you take the orange plug out of the car at the back at the battery there's a plastic faceplate that just pops off with your finger revealing a fuse with the top and a bottom bolt now you put the safety plug back in the battery but you don't slam the connection down you just set it in the hole I did it both ways but this is what the instruction said initially then you take your voltmeter and you measure from one of the silver bolts in the orange plug to ground on the battery like one of the bolts going through the battery case holding it down to the frame of the car I put my clamp on negative there from my fluke meter And I'm using the red probe to probe the silver bolt on the orange plug which is inserted. You're looking for the voltage to go crazy up and down on the scale You said to DC volts you clamp to the chassis bolt holding the battery down and your probe in the silver bolts on the orange safety plug In my case I'm reading 39 or 40 volts it looks like DC and then millivolts is changing rapidly you know between 10:00 and 20 millivolts but the volt side 39 or 40 holds pretty steady from what I understand if that voltage tried to head to zero or go up sky high then the voltage is leaking from the battery and getting to the frame of the car I guess setting the code and wreaking havoc on other things that use lower voltage possibly I am chasing the same problem now there's also something apparently in the inverter that can cause this leakage some kind of tri Delta circuit something another. All this can be read about in various and sundry places. Most people here have seen leakage in the battery tray where modules have become dehydrated because all their hydration leaked to the battery case which essentially is like running voltage to ground. I don't think my newly rebuilt battery personally has this problem but I guess I have to look to eliminate the issue. The person who rebuilt and made my battery that I have now also told me that he believes these hybrid battery computers can be at fault once they've gotten corroded they're very suspect try and find one that not corroded black label and looks clean You can take the four screws off and look inside He seems to think that's more of a problem than not so I have one at the ready Black label sitting right here next to me.

 

I haven't even really tried to clear mine another guy said you had to clear it twice with your generic scanner that you can't even see the code on if you just hit the clear the code button twice All of a sudden the car will boot haven't even attempted that. One day I just waited two or three days in the car ready and started up and I drove it around for a day after I change the CM monitor and all that was putting it back together I noticed that the door ajar light wasn't on with the trunk up. And I knew my battery guy said if I don't see that door ajar light with the door opener the trunk up it's going to be no display when I start the car so I opened and closed the trunk a few times nothing on the display reset the ground got the door open light to magically display on the dash push the button start the car have display all ambers are off and off we go within 24 hours I have the P0AA6 code and the given sub codes and I see nothing electrically the down and dirty test yields me around 40 volts and nothing changing or relatively stable so I have no reason to believe anything's leaking out of the battery so it's on to the HV battery computer which I have a like new one sitting right here looks like I'll be changing it.

 

I don't think so. Here is a thread reviewing other options. I think it mentions some others that can show the freeze frames and INF codes.

Gen2 OBD2 app review | PriusChat

 

Funny thing is . This is a weird code I'm not sure exactly what all has to be seen to set it. But it seems pretty open-ended I have the exact code with the five subcode that takes you right to the battery case funny thing is is the battery case is completely different than what was in the car 72 hours ago but it's still throwing the same code with the same subset in the battery case looking in the battery case yields me nothing. It looks clean it doesn't look like there's any liquid hitting the tray everything very normal considering what I have seen that was running without this code that's been here in my yard and house. So we'll keep pressing on I'm guessing like the kids said who does the batteries maybe change out the battery ECU see what happens with that He said that can be a pretty normal regular thing he sees pretty often It is a part that lot of these battery guys seem to believe once it starts coding something's wrong with the ECM itself mine none of mine look like that but oh well that's where I'm at My electrician friend said he would be doing similar things with the leaking down that's not happening and all of that You're stuck with visual basic check. I'm sure the Toyota manual has you checking a bunch of other items looking for something like 10,000 ohms and then when something doesn't have that you get the energy logo and it says change the ECM so rather than do the bunches of little 10,000 ohm test I just changed the ECM and see if it works I have a few

 

or you could do something wild and crazy like a voltage check between each main relay and the battery case......

 

Yeah I guess that would work too I'm going from the safety plug inserted but not push down the silver bolt on the big fuse to frame of the battery chassis of the car or both that goes through both and I have a steady reading if I move a little bit the millivolts will change but the voltage pretty much is the same 39 40 V DC If I'm seeing what I believe I'm seeing I had it plugged up yesterday and that's the reading I got then I cleared the codes with a generic code scanner twice like previous poster. And then the car booted and I've driven it around the property three or four times eventually I'll push the air conditioning button or something and it will code red triangle and when I shut it off it won't restart until... But I will try that between the relays other than that the car seemingly drives flawless when it's cleared and rebooted there are no lights on the display no codes no check engine light nothing just driving bliss if you will.

 

And I'm not sure what that's going to tell me oh if each relay is not leaking the ground then? I was thinking that maybe further up the line possibly a wire got damaged or something but you would think it'd have to be in some kind of collision or somebody doing something destructive like an animal and I don't see any place looking underneath around anywhere where anything like this has happened and then the battery like I say has been changed and it looks to be in good condition and seem charged and happy when the car is running and driving it goes green back to blue never turns magenta but I haven't run the air in a parking lot to test all that.

 

??? not sure what you mean by "the five subcode that takes you right to the battery case".

The battery is implicated if your subcode is 612. There's a diagram in post #2 you can look at to see what the subcodes are telling you.

The only "five subcode" I can think of is the initial 526, which doesn't tell you anything besides that the car hasn't had time to decide which of 611, 612, 613, or 614 to show you yet.

As for what gets seen to set the code: the high voltage supplied by the battery is nominally DC (would look like a straight line on a 'scope).

The battery ECU generates a weird wiggly wave to superimpose on that:



When the high-voltage system is properly isolated, the battery ECU should not be able to recognize that waveform showing up between the regular 12 volt system and body ground. If it shows up there, that's a problem.

The car decides whether to say 611, 612, 613, or 614 by paying extra attention next time it starts up if there's a 526. If the wave is already showing up before the battery's even connected, it has to be in the battery (612). If it doesn't show up until the car is made READY, but before sending any power to the transaxle, 614. If it doesn't show up until power goes to the transaxle, 613. If it only shows up when running the A/C compressor, 611.

Gen 1 didn't have those fancy INF codes yet, but you could pretty much use that same procedure yourself to figure out where the fault is.

In a scan tool that shows live data, there's a "short wave" item you can look at to see how strongly that wave is showing up.

Funny translation glitch ... most English speakers would see "short wave" and think of radios and listening to Czech operas or something, but I'm pretty sure all Toyota meant was it's a wave ... that the car uses ... to check for a short.

 

In tech what happens It shows the P0AA6 and then I click on the snowflake It opens up a page of black and white text halfway down that page it says something about detail codes 0123 I think are the choices One is the 526 you talk about and two is the 611 or two is the 526 and 3 is the 611 in that list I have to go and plug up and bring the list back up while the car is connected

 

If it's a 611, go check out your A/C compressor and wiring. The stuff in the green box in post #2.

 

The last folks that own this car are the type of people that would have gassed up the car or had it gassed up and worked on at a place that would have just used regular 134a oil so on and so forth so if the compressor is breaking down and becoming a leaking point will just unplugging the big orange plug that goes to the compressor basically solve the leakage problem temporarily? I do think one time the red triangle came on at the moment I push the air conditioning button as in turning the compressor on.

 

Quick enough to find out. Wrap a whole lotta Rescue Tape or something around the loose end....

 

I unplugged the air conditioner put a piece of zip tape over the plug that comes out of the inverter that's held onto the bracket so nothing can be stuck in there get in there easily that will wreak havoc on the HV system. We'll see how that goes It's the only thing that even looks like it could make sense I'm sure there's a way to test the compressor from the orange plug but I don't know exactly how that will go yet I have to look it up I have several extra compressors that were running well on the vehicles they were removed from and capped off and put up.

 

So I'm guessing with my fluke test meter there must be a way I can check the compressor side of the high voltage plug maybe to the case outside to measure the mega ohms of resistance but what spec am I looking for??

 

Tests like that are made with a megohmmeter, a specialized instrument with an extra-high test voltage for making those kinds of tests. More in this old post.

Fluke does make those instruments, as well as ordinary multimeters, but if you have to ask whether the Fluke you have is one of those, then it isn't.

The P0AA6-611 section in the repair manual will have the steps for the testing involved.

 

It's just a 116 so I guess it's just easier change out the compressor from a car that's running without any issues or a new one simple enough.

 

As long as it's "just" the compressor. I have read all the warnings about putting the incorrect oil into the A/C system and causing isolation faults. Gloom & doom about having to replace most of the parts afterward and flushing the oil out, etc.

Haven't seen it myself, but...

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