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P0A80 Check Hybrid System... Wiring Harness???

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by robertwa, Dec 31, 2018.

  1. robertwa

    robertwa Junior Member

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    OK PriusChat peeps. Y'all are awesome, so I need some guidance here.

    I have a 2010 Prius with about 135k miles. I started getting P0A80 codes about a year ago. I didn't act right away, because it would go away for months at a time. I have not gotten any other codes at any point.

    Now, it comes up every 100 miles. Here's what I have done so far and the results:

    1) Took it to the Toyota dealer with the codes reset. They couldn't find anything wrong at that time.
    2) Took it to the Toyota dealer with the P0A80 code active. Their only remedy was to replace the entire HV battery for $3900.
    3) Disassembled the battery and cleaned the copper bus bar plates with vinegar and steel wool. No code for about 4 weeks.
    4) Disassembled and tested cells with multimeter only. No clear standouts in voltage drop, even after sitting for 1 week. Replace copper bus bars with anti-corrosion nickel plated bus bars from GreenTec Auto. No code for ~2 weeks.
    5) Disassemble and tested cells with multimeter and headlight bulb (12v 55W 4.5A). No significant voltage drop with 120 seconds of load (.15v min, .3v max, no big outliers).
    6) Full reconditioning process with Hybrid Automotive Deluxe Reconditioning Package. Started with the 2 cycles, most recently ran 3 cycles. Diminishing returns with each cycle. First time, no code for 2 weeks, most recently, only lasted 100 miles.

    My ICE is running a bit rougher than it has in the past, and there is a very noticeable hesitation when it kicks in now, almost like the car it going to stall. I'm behind on replacing the spark plugs. Don't know if this is related but thought I would mention it. In fact, now that I write this, I'm gonna just order new plugs and install them now. I figure that's $20 in parts that can't hurt.

    The only thing left that I can think of is to replace the bus bars completely, but that is a $150 fix for something that may not be the problem. Given my testing, I feel strongly that the battery is okay, so I hesitate to drop $2-3k to just replace it.

    I've called several shops (Hybrid, Electron) for help over the phone, but obviously they can only do so much remotely.

    Can anyone think of something else I haven't tried/tested yet?

    Or, does anyone know a shop in or around Orlando that I can take the battery pack to for further testing? I'm really good at removing it at this point :)

    Thanks in advance! This forum has saved me thousands of dollars so far!

    PS - if anyone wants a good deal on the Hybrid Automotive Deluxe Reconditioning Package, PM me. I may have one for sale soon!
     
  2. bisco

    bisco cookie crumbler

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    have you considered tech stream diagnostic software?
     
  3. jerrymildred

    jerrymildred Senior Member

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    Nothing in Orlando, but Todd over at Home - Tampa Hybrids Inc. probably knows more about the Prius than all the Toyota dealers put together. It sounds to me like you've eliminated about everything except the harness itself. Todd showed me once how the corrosion can work right up into the sensor wiring and into the connectors. That didn't surprise me having been an electrician on a small island for nine years.
     
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  4. TMR-JWAP

    TMR-JWAP Senior Member

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    What do you mean by disassembled? Down to the point of removing each module from the base plate? Or just popping the harness off?

    Maybe your P0A80 is due to a low HV Isolation resistance instead of a low block/module voltage. A small leak on a module will kill HV isolation, yet have no significant effect on a module's voltage. It also will not provide a subcode for a specific block. Get techstream so you can look at the freezeframe data when the code pops.

    Is there any discoloration or residue on the steel baseplate at the bottom edges of the modules? In the plenum area under the modules? Any dark splotches or white residue is a sign of a module(s) leaking.
     
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  5. robertwa

    robertwa Junior Member

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    Just removed the harness to test individual modules. I haven't checked the baseplate, so that's a good next step.
     
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  6. TMR-JWAP

    TMR-JWAP Senior Member

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    I would say 30% of the batteries I've swapped out have been due module to leakage issues causing the P0A80. The rest were weak modules and would almost always have an additional code present specifying which block was "Block xx becomes weak". (ie P3019=Block 9 becomes weak)
     
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  7. robertwa

    robertwa Junior Member

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    OK, I've completely disassembled the battery and removed the individual modules. There is quite a bit of new corrosion on the wiring harness, even after I installed the anti-corrosion bus bars.

    There's no clear signs of leaking on any of the modules, but I may not know what I'm looking for. The baseplate has spots and corrosion dust all over it. I see two spots in the middle of the baseplate. I took some photos, can y'all see anything that I'm missing?
    Prius baseplate 1.JPG Prius baseplate 2.JPG
     
  8. TMR-JWAP

    TMR-JWAP Senior Member

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    Robert, The portion of the base plate in the photos actually looks pretty good. The photos show the majority of the plate, so if the remaining portion of the plate looks identical, it's a lot cleaner than the ones I've seen with a leak. Once a leak gets to the point of triggering a P0A80, there's no doubt when you see it on the plate. It's typically very obvious.

    Did the dealer provide you with any other information? Freeze frame data from the P0A80?
     
  9. ericbecky

    ericbecky Hybrid Battery Hero

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    You need to get yourself some equipment so that you can see live battery data in the car so you can properly diagnose things.

    Android phone tablet/phone with WiFi access
    Torque pro app ($6)
    Elm 327 bluetooth OBDII adaptor ($20)

    Perhaps one module is fine with no load, but as soon as it has a load it drops.
    Perhaps one of the crimps in the ring terminals is too corroded and has a break in it.
    You could see this if you watched the live data.

    You can ask your Toyota parts department the cost of a new battery if purchased over the counter. I would expect a couple thousand. Certainly way less than $3500.
     
  10. robertwa

    robertwa Junior Member

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    Thanks, Eric!

    Any suggestions for a good iOS app? All my devices are Apple.

    My local Toyota wants $2800 for just the battery after core charge, and $1000 to install it. Plus, no warranty if I install it myself.
     
  11. Tiff

    Tiff Junior Member

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    Have you checked the 12v battery?
     
  12. robertwa

    robertwa Junior Member

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    So, follow up here. I checked everything and it seemed fine. I finally found an iOS app (Dr. Prius) that could give me real-time readings on the cell voltages. Everything ran green until I started driving, then the voltage dropped too low. I ran the Life Expectancy test and it said less than 37% life left, time to replace.

    So I sucked it up and bought the new cell kit from NewPriusBatteries. Install took a day and I'm back up and running.

    I have all my old cells, wiring harness, and vent tubes. @ericbecky, do you know if anyone is buying hybrid battery parts here? What's the typical value?
     
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  13. ericbecky

    ericbecky Hybrid Battery Hero

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    You can check eBay for prices.
     
  14. robertwa

    robertwa Junior Member

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    8 month follow up: I'm over 2,000 miles into the new battery from NewPriusBatteries, and I couldn't be happier. Prius is running like a champ and I'm getting 44 to 47 mpg. My only regret is taking sooooo long to decide to replace my battery. If you are getting the triangle of death, get an app like Dr. Prius to test your life expectancy, and use NewPriusBatteries to buy a replacement if recommended. 1600 bucks and I was back on the road. This was less than half the price for a used battery from the dealer.
     
  15. ericbecky

    ericbecky Hybrid Battery Hero

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    Thank you for checking in.
    Back when this first came out I took the plunge so that others could see whether or not this cylindrical pack was blowing smoke. It worked well enough in my short term test. Good to have people check in with some longer term data points.
    As always, please continue to check in!