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POA80

Discussion in 'Gen 2 Prius Technical Discussion' started by Sharnold, Aug 25, 2019.

  1. Sharnold

    Sharnold Active Member

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    What all issues does this code mean other than HV battery?

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  2. Raytheeagle

    Raytheeagle Senior Member

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    They all deal with the hv battery. There will be subcodes present to guide the next steps;).

    Techstream helps emensely with Prius repairs :).

    Good luck and keep us posted (y).
     
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  3. Sharnold

    Sharnold Active Member

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    The point of the question is to start a thread for others who do not yet have/or bought the techstream technology. I myself started out without the techstream that I have now doing everything with a obd2 reader going by trial and error. Hence starting a possible list of problems related to the P0A80 code.

    Posted via the PriusChat mobile app.
     
  4. Sharnold

    Sharnold Active Member

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    I'll start
    Low voltage on the 12 volt battery
    Faulty code due to overfilling oil
    Faulty ground on the 12 volt due to paint
    Faulty connection on the HV battery service plug

    Anyone else jump in it's a long list and I dont want to be the only one answering


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  5. TMR-JWAP

    TMR-JWAP Senior Member

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    P0A80 means only one thing. The voltage difference between battery blocks is higher than standard. (two trip logic detection). Trouble Area: HV Battery assembly OR Battery ECU. That's directly from the Toyota Guide. And this, in my experience is not a set value, but varies by current load and battery temperature. Many people think it's set at 1.2 volts or something similar, but I've seen plenty of episodes of max-min being greater than that under high load with no trip.

    What could cause the voltage difference to trigger twice? I have yet to see a battery that coded out with a P0A80 and it was a problem outside the HV Battery assembly, so I would stick with items inside the case.

    A weak module, the voltage sensor harness, harness corrosion, ecu plug and ecu corrosion are the main culprits. You could also throw in fastener problems on the module studs, micro cracks on the voltage sensor tabs where the wires crimp to the tab.
     
    #5 TMR-JWAP, Aug 25, 2019
    Last edited: Aug 25, 2019
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  6. Sharnold

    Sharnold Active Member

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    Then again sir we are talking outside of techstream that you must have been privileged to start out with it. If you are running a buy it everyday obd2 reader you will get this code for a multitude of issues and you are missing the point to my post. This is a outside the proverbial box topic. If a typical Prius owner goes to a local part store and has the obd2 read you will get this code for a multitude of reasons. And it can be studied online as how I learned before I purchased techstream this code doesn't always refer to the Hv battery

    Posted via the PriusChat mobile app.
     
    #6 Sharnold, Aug 25, 2019
    Last edited: Aug 25, 2019
  7. RobH

    RobH Senior Member

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    The primary cause of a P0A80 is a failed HV battery module in a 10+ year old car (battery). The solution is to replace the failed module (may work for a few weeks or even months), or just accept that the battery is exhausted.

    Consider what is done if a brake pad is worn out. I suppose you could replace just that pad, but the chances that rest of them are very close to failure as well. Need one brake pad? Replace all of them and any related wear items. Worn out HV battery module? Replace all of them with new or expect to play whack-a-mole until you've replaced all of them. And since those individual replacements are used, don't expect used modules to last as long as new.

    Batteries are wear items. The Prius HV battery typically lasts about 10 years, regardless of mileage.
     
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  8. Skibob

    Skibob Senior Member

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    The bar is set so low to get an old single processor XP laptop and a Mini VCI with Techstream there is simply no excuse not to have one owning a Prius. The car is just to complicated to not own one.
     
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  9. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    I agree with the first part but have seen a P0A80 code not being the fault the of the battery. :confused: In fact one of my fleet of 17 Prius has run for 30K+ miles after setting a valid P0A80 with no battery repair performed. The cause was a botched oil change that fouled the MAF sensor. This disabled the engine and the car was driven until the battery was run down until the code was set. If you run down the battery far enough one cell will always dropout first. This might be what Sharnold was referring to. Running out of gas will also lead to a P0A08 code.

    A poorly running engine and or hybrid system can also appear to be a battery problem without getting to the point of setting a code. It can be hard to tell what is the cause and what is the effect. My point is it's not always the battery.
     
  10. Sharnold

    Sharnold Active Member

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    Ty sir this is exactly what I'm talking about. I've also had a gentleman bring me a Prius that was totalled he repaired that the code P0A80 was showing all due to a short in the inverter pump plug. Basically he wasnt driving the car on the engine only the HV battery as he moved it around from the auction to his garage and as he made repairs. Problem: car was in limp mode and the check engine light was on until he depleted the HV battery then the dreaded triangle of death. After replacing the inverter plug and me charging the HV the car was right as rain.

    Posted via the PriusChat mobile app.