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2012 Prius Intermittent Hybrid Battery Warning

Discussion in 'Gen 3 Prius Technical Discussion' started by Ms.B, Jul 1, 2024.

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  1. Ms.B

    Ms.B New Member

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    Hello everyone,

    I have a 2012 Prius that has had the hybrid battery warning light come across the dash many times in the last 2 years of ownership. I took it to Toyota and they said they couldn’t find ANYTHING wrong with the car. Causing me to unhook the battery EVERY time this light comes on to reset due to no known issue causing this.

    I have had codes read and not noticed anything in particular related to the battery. When the engine turns off from being in hybrid mode it rattles pretty bad. Even after having them engine replaced over a year ago.

    Any suggestions? I’m not sure if it’s the MAP sensor etc, but this car is my daily driver and I really want to fix this problem as it is not safe, when driving on the freeway and the light comes on randomly causing the gas to become slow to respond.
     
    #1 Ms.B, Jul 1, 2024
  2. bisco

    bisco cookie crumbler

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    welcome!
    how many miles on your car?
    is the battery original?
    what codes did the dealership pull?
    who installed the engine?
    was it new or used?
     
    #2 bisco, Jul 1, 2024
  3. Ms.B

    Ms.B New Member

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    Thank you for your reply!
    The car has a whopping 312,000 miles, I have had it since 250 K and it has had regular maintenance. The engine was installed by a somewhat known Prius mechanic in my area, it was a used JDM with very low miles. I believe the battery is original but as I was cleaning out the hybrid filter today i noticed there was clips left out near the fan which makes me think someone has at least looked at the battery. Toyota told me NOTHING was wrong a year ago, so from pulling the codes multiple times myself the only one showing is pending P0180. The car doesn’t have the hybrid light on currently due to disconnecting the 12v and it turning off for a while and only turning on at random times.☹️
     
    #3 Ms.B, Jul 2, 2024
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  4. ASRDogman

    ASRDogman Senior Member

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    Just because it says the hybrid battery is bad, it doesn't mean it is.
    It's the whole hybrid system. Which includes many things.
    You need a good code reader that will read ALL the codes for the hybrid system
    and it's likely you'll get codes so you know where to look.

     
    #4 ASRDogman, Jul 2, 2024
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  5. Ms.B

    Ms.B New Member

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    Thank you! I will try to get an accurate reading.
     
    #5 Ms.B, Jul 2, 2024
  6. Eddie25

    Eddie25 Active Member

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    Yep, as mentioned the light is just telling you something is wrong, which no one can just guess on. Get the code and it'll send you in the right direction.

    I would suggest a cheap OBD2 bluetooth dongle from amazon that works with your phone OS. There are a few free apps that will read codes, (Torque for android and Car Scanner for ios) then you can just leave the dongle plugged in so the next time it happens you just run a code scan and get the codes right there.
     
    #6 Eddie25, Jul 2, 2024
  7. Ms.B

    Ms.B New Member

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    I really appreciate it. I will order it tonight! Thank you:)
     
    #7 Ms.B, Jul 3, 2024
  8. bisco

    bisco cookie crumbler

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    #8 bisco, Jul 3, 2024
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  9. bisco

    bisco cookie crumbler

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    i would take it to thehybrid shop that replaced the engine. might be something simple like a loose hose or connector.
    ask them if the engine came with the egr valve, or if they cleaned up the old one. see here:

    professional-egr-cleaning-resources.236215

    merv is great!
    watch
     
    #9 bisco, Jul 3, 2024
  10. Eddie25

    Eddie25 Active Member

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    (They weren't showing me your first few replies when I wrote my post strangely enough.)

    Unfortunately I'm guessing you probably got p0A80 (not p0180), which is indeed the code for "replace hybrid battery." There are a few things you could check (like corrosion on the buss bars) before you do anything drastic, but probably best left to an experienced DIY'r or pro. Almost any mechanic is just going to use the code to tell you to get a new battery... they might be right, but the fact that it's been going on and off for so long actually would give me hope that it could just be corrosion.
     
    #10 Eddie25, Jul 3, 2024
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