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2009 Prius Error Code P0a80 - Check Engine Light has Since Disappeared

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Chupatty, Jan 4, 2023.

  1. Chupatty

    Chupatty New Member

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    Hi all, I have a 2009 Prius with 140,000 miles. My family has owned it since new and the 'check engine' light recently came on. The Toyota service center found error code P0a80 which I understand suggests a new hybrid battery is needed. I have obtained multiple quotes for this work and of course will have it replaced if necessary to hopefully keep using this wonderful car long into the future.

    However, only a day after the 'check engine' light came on, it went off (literally when I was driving it to the Toyota service center to have it investigated). My question is if that means I may not necessarily need to replace the battery. Prior to the 'check engine' light coming on, the car had sat undriven in my garage for 2 weeks during recent cold weather. I wonder if there's a chance that could have created a temporary issue with the battery.

    My thinking is to keep driving it for now. If and when the 'check engine' light comes on again for the same reason, I would then then get the hybrid battery replaced. I'd love to hear peoples' thoughts on what they think the best approach is.
     
    #1 Chupatty, Jan 4, 2023
  2. Tombukt2

    Tombukt2 Senior Member

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    Yes keep driving If you have a friend that messes with cars regularly you can lift up the rear tray and get to the battery and do some bolts and lift up part of the silver cover and just look at the bus bars and nuts on your car there's going to be a lot of frosting if you want to call it corrosion the white stuff that grows on battery terminal positives a lot things like that are going to be showing I'm pretty sure and your battery is what 13 years old whatever it is I just went through the same thing with my 09 about 10 months ago maybe a slightly longer paid $14.95 or right near that for a new Toyota battery I didn't fool around with any of the remanufactured business for this model. Seeing a lot of green and everything running good since
     
    #2 Tombukt2, Jan 4, 2023
  3. bisco

    bisco cookie crumbler

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    good thought. The battery may be sketchy though and sitting might have dropped the voltage below parameters.
    Have the 12 volt load tested at auto zone in the meantime
     
    #3 bisco, Jan 4, 2023
  4. Chupatty

    Chupatty New Member

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    Thank you both. I've had it looked at by 2 places:
    - Toyota service center - said hybrid battery needs to be replaced ($3,400 and the Service Advisor said he could reduce it to $3,200) but the 12V battery is fine
    - Independent mechanic - said both the hybrid battery ($2,800) AND 12V battery ($320) need to be replaced

    The mixed messages are a bit confusing. As Toyota say the 12V battery is fine, I'm inclined to get the hybrid battery replaced (only if the engine check light comes on again), and could do the 12V battery at a later date if it turns out that's also an issue
     
    #4 Chupatty, Jan 4, 2023
  5. Tombukt2

    Tombukt2 Senior Member

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    Exactly . You can buy hybrid battery for about 1600 now I think . It's an easy change out with very basic hand tools that most everybody has your neighbor yourself somebody that's more of a pain to take the plastic panels out of the trunk to get at it than it is to do anything else you'll need to watch a video You're going to take the front end off your battery it's not anything energized generally and move it to the new rack of cells there are a gajillion videos all over the web
     
    #5 Tombukt2, Jan 4, 2023
  6. mr_guy_mann

    mr_guy_mann Senior Member

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    It is not unusual for a P0A80 code to be "on again- off again" if one or more HV battery modules are JUST barely at the threshold where the ecu detects a fault.

    As the battery deteriorates, lights will come on - stay on. MPGs go down, you might notice the "battery gauge" on the center display (MFD) goes up and down more quickly, reduced performance and louder engine operation (more RPMs).

    Eventually it will set a P30xx code - "battery block xx becomes weak" and operation will be very limited.

    There MIGHT be a fault (corrosion) with the wiring or battery ecu that monitors battery voltage (but that usually sets other codes).

    A 12V battery is a "minor" expense in comparison. It's a consumable item that will need replacement periodically. Depending on the existing 12V's age and what tests were done, I could see one place saying "it's ok" while another says "replace it".

    Personally, I replace a 12V at 5 years- period. Some climates are tough on batteries, and having the car start when I want it to is more important to me than "saving a few bucks" and waiting until it fails.

    Posted via the PriusChat mobile app.
     
    #6 mr_guy_mann, Jan 5, 2023
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