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Failing hybrid battery after 3 weeks of owning 2004. What should I do?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Gen2Boo, Sep 10, 2020.

  1. Gen2Boo

    Gen2Boo New Member

    Joined:
    Sep 10, 2020
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    Location:
    USA
    Vehicle:
    2004 Prius
    Model:
    II
    Background: Just bought a 2004 Prius with 182,000mi. Seller claimed to do a battery test with "professional" equipment in the past month or so after battery failure diagnostic. He was able to determine bad cells with that test and replaced two of them. He even gave me the old ones.

    2nd day: Speedometer lights on dash wouldn't turn on so I unplugged and replugged 12v and everything was fine for that day. I checked 12v at home and at AutoZone and voltage was ok, but not great.

    What happened today: Check engine, VSC, and exclamation point light turned on while driving. Live engine/motor animations indicated that battery was suddenly charging and discharging much faster than usual. While going up a hill the engine was much louder than I've heard it (probably not getting enough/any power from hybrid system). After stopping I realized that battery vent fan was operating at much higher speed than I've ever heard before. Checked OBDII and I have P0A80, P3021, P3000.

    After doing some research it appears I likely fell victim to the classic "sell the car when you think battery is about to die" trick. I'm in New Mexico, so as far as I know, pretty far out of range of any of the local/mobile repair options outside of Toyota dealer. I'm confident in doing the replacement myself but wondering if that's really my only option.

    My main question is if I should immediately just go ahead and look into buying replacement battery and if so, which vendor you folks would recommend. Or, is it possible that the hybrid system has some more life in it and I should check other things or do some other maintenance first?
     
    #1 Gen2Boo, Sep 10, 2020
    Last edited: Sep 10, 2020
  2. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,470
    8,383
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    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    It wouldn't be a surprised to anyone that a 16 year old car with 180k miles would probably need some repairs. Right now since you just bought the car, there's no telling what other problems the car has. The combination meter seems to be failing due to the dash lights not turning on. There may be other items once you get this car on the road and put some miles on it.

    A new HV battery will be the most reliable option. You can buy an aftermarket kit from online for $1600 and it's shipped to your house. That will fix the battery problem but prepare yourself to possibly spending more money later on other repairs.
     
    #2 JC91006, Sep 11, 2020
    SFO, Raytheeagle and The Critic like this.
  3. john1701a

    john1701a Prius Guru

    Joined:
    Jan 6, 2004
    12,747
    5,243
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    Location:
    Minnesota
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    You almost certainly purchased a Prius with a dying battery (more cells). Interestingly, if the engine is still working fine (burning some oil isn't a concern), a replacement of the entire pack will bring the system back to life. I had a friend (best man at my wedding, actually) who ended up doing that for his 2004 last year. The car works fine now.
     
    #3 john1701a, Sep 11, 2020
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