2010 Prius Check Hybrid System Warning - Need Help

Discussion in 'Gen 3 Prius Technical Discussion' started by Michael Short, Jul 10, 2019.

  1. Michael Short

    Michael Short New Member

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    I have a 2010 Prius with 160k miles. I was driving on the freeway on cruise control at 70mph a few nights ago and the "Check Hybrid System" warning appeared on the LED display. There didn't seem to be anything wrong with the car so I drove it home and then drove it to the dealership the following afternoon.

    The dealership came back with the following codes: P0AA6 with an information code of 526. They told me that I needed to start by replacing the hybrid battery. After pressing them for details, I was told the codes were ultimately inconclusive and the problem could be coming from the hybrid battery, the intelligence power module, or the "trans axel".

    I didn't feel comfortable "starting out" with a $3,500 repair in hopes that it'd solve the problem, so I decided to drive the car home and get a second opinion.

    Tonight, a hybrid battery specialist came out and took a look at the car. He ran a few basic voltage tests on the hybrid battery case and on a few of the orange "high voltage plugs" near the engine (I don't know what these are called). None of his tests identified a "voltage leak" and he felt like we should reset the codes to see if the "Check Hybrid System" warning persisted. So he disconnected the 12V battery (which apparently resets the codes), put everything back together, and the "Check Hybrid System" warning was gone when we turned on the car.

    I was told to just drive the car and see if the "Check Hybrid System" warning reappears. If it does, then get the car looked at again as it's likely I have a real problem. If not, then maybe it was just a transient glitch and there was never a real problem in the first place. Sounds reasonable to me, but I'm inexperienced with this kind of situation so I wanted to get some outside perspective.

    What would you guys do if you were in my situation? Just keep driving the car? Have it checked out by someone else? Other?

    Thanks!
     
  2. PriusCamper

    PriusCamper Senior Member

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    Hopefully it goes well for you and lights don't come back, but that's rare... Now's the time to get educated on preventative maintenance to your hybrid system though. If I were you I'd be suspicious of corrosion in the bus bars and voltage sensing wires. Getting that cleaned up, as well as maintenance like cleaning the battery cooling fan and making sure your 12v battery is strong will help eliminate those issues so you can focus on the more expensive stuff once it comes up. Also learn all you can about the lifespan of your hybrid battery and what you can do to prolong it here: FAQ
     
  3. 4shizzel

    4shizzel Junior Member

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    Wow...I got a 2010 Prius with P0AA6 with an information code of 526 also. The dealer told me I'd have to start the repair by replacing the HV battery and it still might not be the problem. How is yours holding out? Did your light ever come back on?

    Thanks
     
  4. PriusCamper

    PriusCamper Senior Member

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    Never underestimate even the most talented mechanic to be so scared of High Voltage work to the point they don't know where to begin in a way that's affordable and maintains customer loyalty. If I lived near you, I'd charge you an hour to put in a loaner hybrid pack to determine if this problem is coming from the pack or elsewhere in the system. Then once the results of that are known, you can narrow it down to more specific diagnosis. Hope you can find someone who's willing to do that?
     
  5. slalomboi

    slalomboi Junior Member

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    To help you eliminate possibilities, I installed a new stereo yesterday and had disconnected the 12V battery as required. Note: I did NOT touch the hybrid battery pack and Test Plug as advised against by others' mistakes. Upon reconnecting the battery I, too, got the "Check Hybrid System" warning light. Everything seemed fine otherwise. I tentatively drove it around nearby but it didn't clear. Per others' suggestions, after several shutoff-restart cycles (maybe 6-9 times?) the error cleared on its own. That sound is a big sigh of relief as I'd replaced the hybrid battery pack completely about 18 months ago ;)
     
  6. PriusCamper

    PriusCamper Senior Member

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    When you say replaced... Did you buy a brand new pack or a rebuilt one?
     
  7. terraks

    terraks New Member

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    My 2013 Prius II (116K miles) showed the "Check Hybrid System" label and 3-4 warning lights on Friday when I went over a bump. I drove it about 40 miles or so until I took it to the dealership today. They called me an said they needed to replace the IPM inverter module, after they do that, they'll run a diagnostic again. I remember getting a letter a year and a half ago or so about a recall and it said that I'd be contacted if my car was part of it. I never was and today when I run the VIN code in a Prius recall page, nothing came up. Anyhow, this seems to be part of a recall and they're replacing the IPM inverter module for free. I hope that does it and that nothing else is wrong. I did test the small battery in the back and it read 12.2V (50% capacity). I'm happy I didn't try to just get rid of the light by using a bunch of different methods shown online. I also hope this recall/free fix does indeed fix the issue. I'll report back.
     
  8. PriusCamper

    PriusCamper Senior Member

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    Your 12v battery needs replacing... There are ways to do that in the $100 range rather than usual $300+ range if you're into DIY and want to learn more?
     
  9. terraks

    terraks New Member

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    The dealership called back, and they said that the IPM replacement took care of the issue. They did a complete check on the car afterwards and they didn't find anything else, except for some lights that were burned out. I will ask them to retest the battery tomorrow when I go pick up the car.

    As a side, they are saying that they need to replace small "market" lights for $120 installed, lights in the front by the flood lights and in the rear on top of the plate. They definitely got defensive when I mentioned that that seemed weird. Seems odd, I may do this myself later.
     
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  10. terraks

    terraks New Member

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    Closing my short saga here. Got the car back, didn't pay for anything regarding the IPM module, just $50 for an oil change and a full check car check up. They said they checked the battery and it was fine. I drove it about 30 miles and everything seems to be working well.
     
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