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Error Code P0AA6 526, Mechanics code reader cannot find any detailed codes. What to do?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by rose908, Aug 25, 2021.

  1. rose908

    rose908 Junior Member

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    My cars red triangle and other lights came on again. Last time it happened(a little over a month ago), I was able to unplug the 12V and get it to drive normally for a bit. It won't go into gear. I had a mechanic come with his detailed code reader and read the codes. We only got P0AA6 526 and not other detailed codes. I have attached the pictures of the code reader screen. The mechanic tested the hybrid battery and the levels looked good. My car is a 2006 with 130,000 miles on it. I really need it to last me a few more years and right now I feel very stressed. The mechanic said I should just give up on the car and buy a new one. The market doesn't seem too good right now for used or new cars and I don't have a lot of money I can dump on a car. I don't know what to do:(. I have attached the pictures of the scanner image000000 (6).jpg image000000 (5).jpg image000000 (4).jpg image000000 (3).jpg image000000 (2).jpg image000000 (1).jpg image000000.jpg image000000 (6).jpg image000000 (5).jpg image000000 (6).jpg image000000 (5).jpg image000000 (4).jpg image000000 (3).jpg image000000 (2).jpg image000000 (1).jpg
     
  2. bisco

    bisco cookie crumbler

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    you need a dealer, or mech with toyota tech stream diagnostic software.

    edit: for now, you know there is a high voltage leak that could be anywhere. some people start inside the battery, and inspect the wire harness and the connections at the inverter, transaxle and a/c compressor.
     
    #2 bisco, Aug 25, 2021
    Last edited: Aug 25, 2021
  3. rose908

    rose908 Junior Member

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    The mechanic works for a toyota dealer I believe. Do they use different scanners? How likely is it that this is fixable (if even discoverable) for under 3k that will last me for 3+ years? If I clear the codes by unplugging the 12v to get it to the mechanic will they be able to diagnose the car?
     
  4. bisco

    bisco cookie crumbler

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    it looks like he is using tech stream, see my edit above
     
  5. rose908

    rose908 Junior Member

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    So can I clear the codes to drive my car to a prius mechanic? also, can they check the inverter without the codes or without an expertise in prius vehicles?
     
  6. bisco

    bisco cookie crumbler

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    you can try disconnecting the 12v. sometimes it will allow you to drive it until the next time you shut it off
     
  7. bisco

    bisco cookie crumbler

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    if this mech works for a dealer, he should be able to track down the problem. not sure why he's telling you to get another car
     
  8. dolj

    dolj Senior Member

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    If he was a good hybrid mechanic he would know to cycle the car (to IG-ON or READY) once more which would set the second INF code.
     
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  9. Raytheeagle

    Raytheeagle Senior Member

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    Start with the 526 INF code for the repair manual next steps ;).

    Good luck and keep us posted (y).
     
  10. Travis Decker

    Travis Decker Active Member

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    Guy just needs to look at SHORT WAVE HIGHEST VAL and use techstream and brain to figure out location of short. If that’s above 3.6 V it’s not currently shorted.

    ready on in neutral what is it

    ready on in reverse what is it

    ig on not ready (battery is only thing in play with SMRs open) what is it

    AC on what is it

    These are usually pretty easy to fix it’s just nobody knows what shortwave highest value means
     
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  11. ChapmanF

    ChapmanF Senior Member

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    The car posts INF code 526 as a "note to self" so that the next time it starts, it will go through a modified starting procedure and try to identify the area of the leakage, and then set a second INF code.

    So you can definitely catch it at times when there is still only 526. Sometimes people have a mindset of "clear the code and see if it comes back", which of course guarantees they will keep seeing only 526.
     
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  12. TMR-JWAP

    TMR-JWAP Senior Member

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    The photos show SWHV is currently 4.99v, the highest possible.
    The car is most likely not in ready mode at the time of the 4.99v reading, since 12v system is showing as 11.x, HV battery amps are 0, engine at 91F and 0 rpm.
    The freeze frame data shows the car was @ 180F and in ready mode when it coded.
    So, without being there, and based only on that, the problem could very well be somewhere other than the HV battery.
     
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  13. SFO

    SFO Senior Member

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  14. simonfunk

    simonfunk New Member

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    How do you do this with a Gen 2? It won't even try to start once the P0AA6 is set.
     
  15. dolj

    dolj Senior Member

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    You don't actually need to get it to "READY", you just need to go through the motions of attempting to start it so it cycles one more time.
     
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  16. simonfunk

    simonfunk New Member

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    Are there *any* mobile apps that can read these codes? I have one ("inCarDoc" on android) that reads the P0AA6, but it does not get a freeze frame with it, which I gather is where these codes should be. It does get freeze frames for other codes (standard ones, at least), so it has the ability, so I don't know if the app is just being dumb here or if there's a special way to ask for freeze frames for the P0AA6, or if my car is just not generating freeze frames for some reason. (To be clear, I cannot even get the 526. I assume if I could get the 526, I could get the next one per above.) Basically I'm confused why it's so hard to get these codes -- it looks like they are in a standard freeze frame, which I would think most code readers could get.
     
  17. dolj

    dolj Senior Member

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    I imagine it is to do with the programming effort that would go into decoding and translating every conceivable page of freeze-frame data.

    The small amount paid (if any) for these mobile apps will not incentivize that much effort.

    You get what you pay for.
     
  18. simonfunk

    simonfunk New Member

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    From a cursory look it seemed like freezeframe data is pretty standard -- just a list of field code/string, and there are standard field codes for generic information ('INF') which is where these 612 and such codes appear to go. So, it *seemed* like any app that knows enough to fetch and describe the P0AA6 should easily also display any freezeframe data (with info fields) that came with it (even if some of the field codes may not be translated to english).

    But.... empirically this doesn't seem to be true, so I guess there is something more custom than I realize somewhere...
     
  19. Marty2go

    Marty2go Junior Member

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  20. douglasjre

    douglasjre Senior Member

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    That guy brought a tough book home from The dealership. That was awfully nice of him and risky because he could lose his job. Don't even ask him to do that again. If he clicked on the blue snowflake next to the code on the main screen it should have opened up the hysteresis with with five event recordings of the parameters of what was happening at the time. Nonetheless something is shorting to the chassis inside the battery pack. You probably have a plethora of semi-metallic dust or some really dirty bus bars. There is a voltage mismatch somewhere in the pack. If you're going to go that far and open the pack you're going to replace all the batteries with brand new, and replace the bus bars while you're there. You still have to do some old fashioned diagnostics with a digital multimeter and your high power gloves. If you're not qualified to do this then don't because you're going to die. Find a repair shop that is qualified and don't buy used batteries. You should use a resistor to apply load to cells with alligator clips and measure voltage as you go because batteries can look totally different under load than they do at resting state. Dirty bus bars cause sparking which are decreased amperage and spiked voltage during charging
     
    #20 douglasjre, Aug 31, 2022
    Last edited: Aug 31, 2022