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P0A80 code questions

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by koukilights, Mar 27, 2018.

  1. koukilights

    koukilights Junior Member

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    I got a prius with 176k miles and a bad battery pack. It had 2 modules that were shot, one at 6.5 volts and another at 1.3. It was so bad it couldn't even kick the ICE on

    I replaced the 2 bad modules and now it runs and drives seemingly like it should. But a day after I installed the whole pack back in the red triangle and P0A80 code came up, I cleared it and it seemed to run without any issue. Then the next day I was scanning for codes and it came up with the P0A80 code again but it was just pending, no red triangle.

    I've put 140 miles on it since I replaced the bad battery modules and the code has only come up twice, once for real, once only pending

    The voltages of each battery module pair (blocks) as read from my torque pro app seem pretty close, the most I've seen of a difference between pairs was .4 volts but that was only briefly, they're mostly .1 to .2 volts away from each other. From what I've read that .4 volts might be enough to trip the code?

    When I replaced the battery modules I was dumb and forgot to note which modules the wires clipped onto on the bottom of the pack, I ended up clipping them back on in roughly the area I thought they came off of. Would that affect anything?

    Would a bad auxiliary 12v battery affect anything? It sits unloaded at about 11.6v and with the start button pressed twice (auxiliary mode?) it sits at about 11.3 or 11.4. I know it's low and I should replace it but I didn't know if it would affect the P0A80 code
     
    #1 koukilights, Mar 27, 2018
  2. k1ngn0thing

    k1ngn0thing Member

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    .4 might trip it, mine came on at less. You could try balancing the pack if not perform a complete reconditioning. Note that the equipment for this will cost at most $700 shipped if you go the deluxe hybrid automotive kit. It made a noticeable difference in my experience and can't say I regret the purchase. It can be used periodically to extend the life of the pack.

    There's probably a sub-code that your current scanner isn't reading. Odds are it is what you think but if you want to be certain you should try to get it read. Can't hurt to replace the failing 12v either.


    Sensor locations on bottom of modules wouldn't do it, they just measure air temp.
     
    #2 k1ngn0thing, Mar 27, 2018
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  3. bisco

    bisco cookie crumbler

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    you definitely need a new 12v.
     
    #3 bisco, Mar 28, 2018
  4. ericbecky

    ericbecky Hybrid Battery Hero

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    It would be good if you could watch the block voltage data live.
    Buy a Elm 327 Bluetooth OBDII reader, Torque Pro app. Use a android phone/tablet.
    Cost you under $50

    Also what spec did you set your torque wrench when tightening the nuts on module posts and contactor posts?
    They can't be too tight or too loose.
     
    #4 ericbecky, Mar 28, 2018
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  5. koukilights

    koukilights Junior Member

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    I have been using an elm 327 and torque pro, that's where I've been getting my block voltage readings from and what I used to run my check engine light code

    I didn't use a torque wrench but I just tightened them to snug, I'd guess 10 foot pounds or so
     
    #5 koukilights, Mar 28, 2018
  6. ericbecky

    ericbecky Hybrid Battery Hero

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    Watch the block data live while under load.
    Outliers will show up pretty easily.
    Unlikely .4 would trip the code.
    Is Delta SOC Les than 20?

    I would test the 12v with a load tester. Replace if needed.
     
    #6 ericbecky, Mar 28, 2018
  7. koukilights

    koukilights Junior Member

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    ok, I'll watch it next time, the voltages do fluctuate pretty quickly though

    I haven't checked the Delta SOC, but I'll pull up the monitor and keep an eye on it

    The 12v battery is pretty shot, I'm 99% sure of that at this point
     
    #7 koukilights, Mar 28, 2018
  8. Hybrid Battery Exchange

    Hybrid Battery Exchange Member

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    Look at the freeze frame data for the P0A80 code, usually shows all 14 blocks so you can see why the code was tripped.

    1) You have one or more weak modules where a cell drops out
    2) You didn't tighten down the battery posts to spec
    3) Too much corrosion on the sensing harness and sensing ECU plug to read voltage accurately.
     
    #8 Hybrid Battery Exchange, Mar 29, 2018
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  9. koukilights

    koukilights Junior Member

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    The delta SOC didn't change at all. It stayed rock steady at .7% what does that mean?
     
    #9 koukilights, Mar 29, 2018
  10. Hybrid Battery Exchange

    Hybrid Battery Exchange Member

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    Minimal initial voltage deviation between blocks followed by no deviation at all outside of defined parameters. Block lo/hi at various SOC (once the car calculated it's SOC after reset) would be more useful information since we don't actually know the exact formula used for delta SOC, no way to translate 0.7% to voltage numbers. Under 20% is good according to Toyota.
     
    #10 Hybrid Battery Exchange, Mar 30, 2018
    Last edited: Mar 30, 2018
  11. koukilights

    koukilights Junior Member

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    so does that mean my battery pack is in pretty good health? Something else triggered the P0A80 code? I've driven the prius about 100 miles since the last time the light came on and there hasn't been any pending or solid codes
     
    #11 koukilights, Mar 31, 2018
  12. Hybrid Battery Exchange

    Hybrid Battery Exchange Member

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    Delta SOC in your case is meaningless, don't even look at this number to tell you anything if your battery pack is not fully functional. You need to look at the freeze frame data that will point to the actual problem. One or more of your battery blocks deviated by 1.2 volts or more, indicating a cell failure thus the P0A80.
     
    #12 Hybrid Battery Exchange, Mar 31, 2018
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