Should I replace hybrid battery & keep car, or something else?

Discussion in 'Gen 2 Prius Main Forum' started by CT Prius 07, May 23, 2022.

  1. CT Prius 07

    CT Prius 07 New Member

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    Hello Prius Chat - Your take on my situation would be most welcome. How do I know if the hybrid battery is the culprit, when I was getting better than usual mpg, car felt fine until very recently, but all check engine lights on?

    This is a 2007 Prius, approx 170K miles. Never had a problem in the 9 years I've owned it... until the last 10 days when all check engine lights and master warning signal light came on 20 miles into an interstate trip. Just had the snows removed earlier that day. Pulled over, turned car off, checked gas cap. When car restarted (easily) master signal and check engine light on, but not (!) or VSC. Car felt like it was driving normally, but I returned home driving slowly.
    • Next day: Mechanic said no diagnostic codes showed except possibly a weak 12v battery. He reset the warning lights. No apparent leaks or low fluid levels.

    • 2 days later: 12V Battery check: good .

    • Drove around locally for a few more days, no problems. LIghts stayed off. Car felt normal. Good mpg.

    • Drove to neighboring state, about 80-90 highway miles all check engine lights & master warning signal back on. Stopped, turned off car, checked gas cap. Restarted car. Only check engine & master warning signal on, (!) and VSC went off. Car felt fine and was getting better mpg than usual.

    • On way home from out of state, stopped at Toyota dealership. Diagnostic reader showed no codes. Lights back on after 10-15miles, but otherwise car drove fine except no cruise control. Very good mpg.

    • Driving around town, warning lights go on and off, usually "just" master signal & engine. Sometime also (!) and VSC.

    • Then a few days ago, acceleration started feeling funny during local driving. Car maintained speed while foot off gas, as if on cruise. Also, car accelerated briefly on its own while foot off the pedal. Also, car sounded like engine was racing after driving just 1-2 miles. Fluid levels looked good.

    • Had car towed to dealer for diagnosis.

    • VERDICT: $7700 worth of work needed, including new hybrid battery because 1 cell was failing ($2700). Plus: New brake pads, new front brakes, replace head gasket, fix leaking CV joint, fix rodent damage behind cabin filter, oil leak, inverter something ... among other things. Wasn't able to include link to the mechanic's videos showing everything, unfortunately.

    • What should I do?! Replace hybrid battery with new one? With a refurbished one? Invest in another used Prius for $15K or less?
    Many thanks if anyone has any serious ideas about what to do. Money is an object.
     
  2. nancytheprius

    nancytheprius Member

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    have you checked around the 12V battery? maybe the connections are weird or off or something?

    As far as the hybrid battery, has it fluctuated from full to empty a lot recently? Would hybrid battery failure surprise you right now? Definitely is an old battery if it’s original. Maybe replace that if it’s failed and see if that solves all the issues assuming the 12V is fine.

    How long do you need the vehicle/want to keep it?
     
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  3. PriusCamper

    PriusCamper Senior Member

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    Dealership is making a list of every possible expensive thing you "need" replaced to exploit you rather than help you... I've seen many cases where they recommend replacing battery pack entirely when it can quickly be repaired with a $50 voltage sensing harness. At this point you need to be able to read and clear the error codes directly so we can help you decide on least expensive repairs. A device like this one can be hooked up to Dr. Prius app and other apps on your phone: Panlong Bluetooth OBD2 OBDII Car Diagnostic Scanner Code Reader Check Engine ... | eBay
     
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  4. CT Prius 07

    CT Prius 07 New Member

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    - Thanks. Yes I have noticed the battery fluctuating a bit just the last few days, but given the car's felt fine and getting good mileage, the hybrid battery dying now does seem surprising ... even though it is original. :) ... I guess if I sink a good chunk of change into the car I'd keep it a few more years.
     
  5. CT Prius 07

    CT Prius 07 New Member

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    Thanks for that link and your reply. I am wary of that super long list of repairs. But then again, I've had to do nothing but replace a headlight, the wipers, and the 12v battery, and tires, the whole time I've owned it. The car is still at the dealer and I wouldn't chance driving it home right now. I'll see what more I can find out about the error codes and definitely look into the code reader you suggest. The mechanic was pretty specific about everything else but the error codes. I guess I could ask for some snapshots of their diagnostics, and I'll ask about a voltage sensing harness too!
     
  6. PriusCamper

    PriusCamper Senior Member

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    It really comes down to you or a friend or family member who's worked on their own cars before, used to be a mechanic, or still works as a mechanic being willing to read up on doing the repair work for lowest price rather than highest price. We at PriusChat can explain in great detail whatever you want to fix. Probably too much detail... But if you or others want to learn its relatively simple stuff...
     
  7. ski.dive

    ski.dive Active Member

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    Take the car to a local PRIUS mechanic=Not the dealer...
     
  8. 2010moneypit?

    2010moneypit? Member

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    Stay away from the dealer!!
     
  9. Tombukt2

    Tombukt2 Senior Member

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    Essentially a Yaris . Corolla family of cars . Easy to work on . Most scared of voltage ! Remove orange plug and that issue is over. Folks are scared of electricity because they can't see it.
     
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  10. Wrecit

    Wrecit Member

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    As for doing a diy on your track battery. I am a carpenter and can bend a nail with the best of them. Electric not so much and I have a paranoid wife. Saying that I pulled my track battery last night and put in project lithium cells.

    The hardest part of the whole operation was the neighbors seeing me wearing the pretty red rubber gloves with flowered cuffs that my wife insisted I wear the whole time

    I understand that swapping a sell or 3 is a bit more complicated but if you go with a new pack of cells like project lithium or New Prius Battery s (both companies are Prius chat members) then watching a video 2 or 3 times (or 8 like me lol) and the swap is fairly easy.
     
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