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P0aa6 with no subcode after head gasket replacement

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Kenneth Brock, Sep 15, 2022.

  1. Kenneth Brock

    Kenneth Brock New Member

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    Hey everyone, I'm a long time reader and first time poster but I'm pretty confused and can't find any information anywhere so here's the story...
    As the title suggests I am getting no sub code for my P0AA6 code.
    Two weeks ago my car informed me that it needed its head gasket changed with all of the typical signs and symptoms. As I couldn't afford $4,000 to have a shop replace it I took on the endeavor myself which was quite the ordeal. After one week of tearing apart the engine and putting it back together I went to fire it up for the first time and there was no shaking and the car was running very smooth. As I started patting myself on the back a new code popped up on my dashboard... P0AA6. So apparently I'm getting a high voltage leak somewhere.
    I personally believe it being my hybrid battery is an extremely low probability because I've never seen this code before and it coincidentally popped up right after the head gasket change. When I took it to a mechanic they were not able to read any sub codes so now I have to attempt to spend $200 at Toyota to see if they possibly can but I'm wondering if anyone on here has a better idea.

    My best guess is that it has to do with the wiring harness because when I was working on the head gasket I moved the wiring harness out of the way by flipping it over the electric engine and leaving it there.

    The thing that confuses me however is that none of the high voltage orange cables are really too involved with the wiring harness for the engine for the job I did. Does anyone know how I can safely isolate where the issue is coming from? I have a voltmeter some tools and I can do attitude. Any thoughts?
     
  2. Tombukt2

    Tombukt2 Senior Member

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    How long has the car been off the road not running while you did the head gasket job another week so how long really 9 10 12 days etc? Right after I change the engine in my car instead of doing the head gasket and all that or after I attempted to head gasket and found the skirt broke and the piston rolled over and ruined the motor. I had a bunch of these problems and turned out to be corrosion on all of my bus bars and the original 2013 battery
     
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  3. ChapmanF

    ChapmanF Senior Member

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    It might be worthwhile to consider getting a scan tool of your own that is able to read all of your car's codes and subcodes. It is a huge hassle to have to rely on other shops or dealers even just to find out what your car is telling you is wrong.

    A lot of people find a way to run Techstream. There seem to be a bunch of other good options, too, these days. I don't know of a thread comparing them that is specific to Gen 3, but there is this thread for Gen 2 that might be a decent place to start:

    Gen2 OBD2 app review | PriusChat
     
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  4. rjparker

    rjparker Tu Humilde Sirviente

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    Did you remove the ac compressor cable? It is high voltage.
     
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  5. Kenneth Brock

    Kenneth Brock New Member

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    It took me 8 days

    Yeah only the black one to the wiring harness. I went back in and unplugged it to check the pins (they looked good) and make sure everything was dry from anyc oolant spilling on the virtual plug. I plugged it all back in and the code still came up

    Aren't you able to just pull the bus bars and clean them all? I know it's a pain in the butt but if it's just corrosion can't you just clean it up?
     
    #5 Kenneth Brock, Sep 15, 2022
    Last edited by a moderator: Sep 16, 2022
  6. Mendel Leisk

    Mendel Leisk Senior Member

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  7. Tombukt2

    Tombukt2 Senior Member

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    During my mess with replacing the engine in the 13 when I initially put the engine back in and hung the compressor back on the new engine which was still plugged up I kept getting an AC error code something to do with the power the orange cable part of it but there was nothing wrong with the cable it was all plugged up I unplugged the air conditioner for about a month got the car running everything like it's supposed to and then one day while I was out driving I just randomly in a parking lot at Sheetz I think plugged back up the air conditioning made the old lady turn the car back on immediately put on the air and it all started to work mind you this system was not discharged to replace the engine The compressor was removed and hung in the engine bay and then when I reconnected everything I had all kinds of power errors high voltage power errors and the main one I eliminated by unplugging the compressor that thing was drain in the battery down as fast as it was plugged up if I turned it on it went from a full battery to zero and 40 seconds minute 90 maybe I don't know but I didn't fix anything I just left it unplugged for a couple weeks and then when it got hot enough and I just didn't want to fool with it anymore I plugged it up and it started working the orange power cable to the compressor.
     
  8. ChapmanF

    ChapmanF Senior Member

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    We have a bunch of threads on P0AA6 around; the weird thing about that one is how little useful information about P0AA6 is in it. There's some, but it got all sidetracked about lug torque and high connection resistance, which isn't what P0AA6 is about, and then a later poster tagged on with the same sidetrack. Most of the other P0AA6 threads are more helpful than that. :)

    So, most of our threads about P0AA6 are in the Gen 2 forum, and they show this handy diagram for where the isolation fault is in the high-voltage system, according to which P0AA6 INF code you have (611, 612, 613, or 614).

    [​IMG]

    You can use pretty much the same picture for Gen 3, but you have to remember one thing that changed between Gen 2 and Gen 3. The A/C Inverter is part of the inverter assembly in Gen 2, but it's part of the A/C compressor itself in Gen 3. That means in Gen 3, the orange cable from inverter assembly to compressor is part of the 614 area (in Gen 2, it falls under 611). In Gen 3, the only parts that can give code 611 are inside the compressor itself.
     
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  9. Mendel Leisk

    Mendel Leisk Senior Member

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    Poster likely meant vertical. I concur; it’s like a rain gauge, if you do something like pressure wash.