Check Hybrid System code POA80

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Trudimoon, Jan 29, 2019.

  1. Trudimoon

    Trudimoon New Member

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    Hello everyone!
    This is my first time posting on here so I apologize if this questions has been made before. This is going to be a long post sorry!
    I have a 2010 prius with 175,000 miles on it, I bought it used with almost 100,000 miles on it(it was a fleet vehicle for Toyota). Up to this past year the car was amazing. On October 10th the head gasket blew, so instead of repairing it I decided to replace the engine. I had been warned by a friend that soon after the engine blew the hybrid battery was going to go. Well a month later on November 13 the 12v battery died. So I replaced it with a Duralast I bought at Autozone because that's the only one they had available. Then about 2 weeks later the Check Hybrid System warning came on. When the light came on the car was running fine but just on the gas engine not the hybrid engine. I unplugged the battery and it started working properly again(using both engines). I did notice that it felt like the car would struggle a bit when the battery was depleted completely and switching to the gas engine. Two weeks later the check hybrid system light came on again with the code P0A80 replace hybrid battery pack. Took it in to have the cells checked and 3 were dead so they were replaced. Two weeks later the check hybrid system light came on again. The permanent code never cleared since about December 1st. So took it to the mechanic again and said he couldn't figure out what was wrong, he thought the modules might be have been fried so he replaced those for free. Then two weeks later the light came on again. As I said before it happened when I was on the hybrid battery for a while and was completely depleted and needed to change over. For example, it traffic. My husband decided that it might be the crappy Duralast we bought at Autozone so we switched to an Optima yellow top as many people suggested. But we ran a quick test to see if it solved the problem and as soon as the battery depleted the pending code popped up on the OBD II reader. The warning light didn't come on but the pending code did. Before that moment the hybrid battery was charging properly and everything seems normal once code comes on it goes straight to gas engine only. I have an appointment to have the J0V recall done tomorrow but I don't know if that will help. I was wondering if anyone here has any ideas as far as what it could be causing this issue?
    New engine, new 12V battery, all cells working properly in hybrid battery, inverter coolant full and moving while car is on.
     
  2. Grit

    Grit Senior Member

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    Long posts are great for troubleshooting, helps narrow things down (y)

    Code points to troubleshoot HV batt as you found. After replacing a few cells already and things were fine for a while, then other cells went bad, sounds like the other packs are going bad also but slowly, and replace others. Here we call it the game of wack o mole; I’ll let you ponder that one. Check if the buss bars needs deoxiding, and torqued down correctly. After that, rebalance with grid charger or get an entire different HV battery.
     
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  3. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    This is not a statement that makes any sense. There is no "gas engine" and "hybrid engine". There is a single gas engine yes. But it is coupled to the wheels via 2 MG's (Motor Generators, i.e. electric motors). It all works as one unit. It is not possible for the gas engine to ever provide any direct motive energy to the wheels of the vehicle. The best the gas engine can do is generate electricity via MG1 and feed it to the inverter to be used by MG2 to spin the wheels.

    All that means is that the car was not using the capacity in the battery pack, or the battery pack had no capacity. The first scenario can be had when the battery is really hot or when the inverter is really hot. The second can happen for lots of reasons, the biggest being age.

    Where did you take it take replaced 3 battery modules out of your 28 module pack? How long were you there for service? If you say less than a day, then the repair was crap. You can't just jimmy in 3 random modules, it doesn't work that way.

    Not surprising. Not only are you playing whack-a-mole, but your previous "repair" was the absolute bare minimum needed to get on the road and lasting 2 weeks is pretty good.

    Your hybrid battery is dead. End of story. There is nothing to diagnose. The "repair" you had the shop do was terrible. For any type of module replacement to work, you need to find modules that are close in capacity, internal resistance, etc to the ones already in the car. You have 28 modules in there that were paired from the factory by the fact that they were made at the same time and put into service at the same time. 3 died. Now you need to find 3 modules that have "seen what your modules have seen" so that they are in a very similar state of health. This is not hard, but it is like looking for 3 needles in a haystack. If your haystack consists of an alley mechanic with 30 modules on the shelf, the likelyhood of finding 3 exact replacement modules is nearly zero. Places that do this for a living with literally tens of thousands of modules sitting around are the only way for this to work. And even then you're looking at a temporary repair because most of the donors are so old now.

    You have a couple options:

    (1) Continue playing whack-a-mole. You should get a week or more out of each swap. Each swap will require your vehicle to be down for 2-4 hours plus the time of you going there and back, etc. If you value your time at $0/hr, or have nothing better to do, then why not.

    (2) Buy a new battery. Your options are (a) the dealership or (b) NewPriusBatteries.com.

    (3) Junk the car
     
  4. Trudimoon

    Trudimoon New Member

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    You're probably right. The dude took days but that doesn't mean he did a great job. When I took it in the second time he told me all the cells where perfect and he didn't understand why it wasn't working. I am going to buy a new car this week but I was hoping I could fix the problem ourselves seeing as how the car probably isn't worth anything, we really don't have anything to lose. If anything we would have an extra car.
     
  5. bisco

    bisco cookie crumbler

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    get tech stream and a subscription to the service manual
     
  6. Trudimoon

    Trudimoon New Member

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    Well I wanted to update everyone, turns out it was my 12V. Took my car into Toyota to get recall J0V done and a diagnosis. Everything was looked over and was told everything was fine. Since I changed my battery the check hybrid system light hasn’t come on and my car is working great! Thank you for your suggestions...except 2k1toster! Not only did he insult me but i would have have wasted so much money listening to him.
     
  7. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    Sorry you feel that way.

    But to be clear, when you replace or even disconnect the 12v battery, the codes get cleared. Meaning if you had an issue the car masks it now.

    As I've said many times after you get your first battery replacement indicator you're good to drive usually for a few more months or even a year. You've been warned. Most likely the code will popup again in the future. Every subsequent time it pops up you'll have less and less time to when it comes back.

    I would start budgeting for a new battery now so that later this year when it throws codes again, you will be in a good place to replace it. If you wait until it's an emergency you'll be paying emergency prices. If you don't want a new battery use these few months to trade the car in.
     
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  8. bisco

    bisco cookie crumbler

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    Dang, how did I miss that?(n)
     
  9. bisco

    bisco cookie crumbler

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    Wait, I know. It was all the 12v replacents in the o/p.
    Yeah, that’s it.(y)
     
  10. Grit

    Grit Senior Member

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    The gophers are taking longer to surface on this next round.
     
  11. Trudimoon

    Trudimoon New Member

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    So it turned out that it WAS the 12V as much as you people want to deny it and insult and doubt my wife. (If you don’t get it by now, this is her husband who she referenced in her first post.)
    Anyway, I’ll explain. With the replaced cells in the hybrid battery, it was now holding a longer charge meaning that the ICE wasn’t having to turn over and run as much or as long meaning that everything running off of the 12V was now having to run longer and with a baseline Ah rating, the battery voltage was dropping to approximate 11.2v upon changeover. At this point, the computer saw that it didn’t have the required 12.4~8v in order to initiate changeover via the relay bank and hybrid battery module and it threw a code because it sensed a fault.

    As for my experience with things of this nature, I’m a machinist/welder/metal fabricator with approximately 20 years working on vehicles along with experience customizing and installing handicapped accessible systems in cars, trucks, and vans.
     
  12. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Take a look at the links in his signature, he might be your hybrid battery saviour.
     
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  13. Grit

    Grit Senior Member

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    But I want to see the OP to clear the final stage of wack o mole, it's quite the game from what I heard.
     
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  14. Edyb

    Edyb New Member

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    I have a 2010 prius the motor blew up so I replaced the motor, when I picked up the mechanic told me that he couldn't get the "check hybrid system" message off but that the car was running "fine" so I took it home, unplugged the negative on the 12 V battery for a few mins and the message went away for a bit and it came back, what puzzle me is that there is no "check engine" on it so obviously my OBD II doesn't read any codes, the car seems to run normal, it switches from electric to gas normally, but doesn't let me switch from power to ev mode, any ideas?
     
  15. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Need to read the codes. Dealership can do it.
     
  16. Edyb

    Edyb New Member

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    UPDATE!! Took it to the Dealer and they found out that part of the hybrid was disconnected... Ridiculous. I'll have a talk with my mechanic today, thanks!
     
  17. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Good that it was something simple. Don't go to hard on the mechanic(s); it is easy as pie to miss something. Also, seems strange that the car would be ok for extended time after they worked on it, and then something goes off. Could also be related to your battery install??

    Hard to say what that could be. Any paperwork with more info?
     
  18. Matt BB

    Matt BB New Member

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    I'm having a similar problem. Can you tell me what part of the hybrid was disconnected?
     
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