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"Empty" battery and check engine light

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ReisheJ, Jun 10, 2017.

  1. ReisheJ

    ReisheJ New Member

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    Hi--

    I have a 2004 Prius. We had both the 12-volt and the hybrid battery replaced last year; the replacement hybrid battery is from GreenTec. The GreenTec battery failed within 6 months and they replaced it.

    My husband was out and about today. He got in the car to come home, started it up and drove less than a mile. He noticed that the Check Engine light had come on and the display indicated that the hybrid battery was fully drained. He pulled over where it was safely possible and ran the engine to recharge the battery; within minutes the display indicated that it was in the "safely charged" range, so he drove the car home. The Check Engine light remained on.

    We attached it to a home diagnostic tool, which gave us a "failed connection"-type message, so then he took it to a garage, whose diagnostic tool found no error codes. We were able, however, to turn off the Check Engine light. At present the battery indicates it is charged within the normal range.

    FWIW he noticed once before that the battery was fully drained, but no Check Engine light, and by running the engine a few minutes he was able to charge it (or rather, make the display indicate that it was charged) and continue on his way.

    There are several road trips on our horizon and the uncertainty concerns me, I don't like not knowing where the problem is, since I don't want to just assume it's the actual battery. Any advice would be appreciated.

    Thank you!
     
  2. goldfinger

    goldfinger Active Member

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    Refurb batteries don't seem to hold up. You could try a battery from a wreck. Anything from 2004 to 2009 fits, so look for newer with low miles. Make sure it's actually from an untouched wreck, otherwise it's another refurb.

    Even if you had a new battery your car is still 13 years old. It's no longer a trip car. Rent a nice new car from a national agency. If it breaks down the agency will bring you a new one and on you go.
     
  3. JC91006

    JC91006 Senior Member

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    You most likely have an intermittent error with the catalytic converter going bad. The check engine light will come and go for a while and then stay constantly on when it fails completely.

    I don't think you have a battery issue
     
  4. windstrings

    windstrings Certified Prius Breeder

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    It's largely dependent upon who reconditioned it... Matching cells is a time intensive operation and open to error and less than perfect matching.
    A good recondition should give you another 100k miles.

    Do you have iffy startup power? And maybe less gas mileage?

    Check out for a comparison.
    Services | Hometown Hybrids

    Warranty tells you a lot as to how confident they are in their own work.
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I agree with the previous comment that your car in its current condtion is not suitable for road trips.

    If you need to use it on long trips all existing issues must be resolved first, unless you like the drama of being stuck roadside.

    Assuming the traction battery has failed you would do better having a new battery from a Toyota dealership installed; or else buy a used battery from a G3 Prius (2010 - 2015 model years) with moderate miles and move the 28 modules into your traction battery case.

    If you want to be self-sufficient regarding retrieval of diagnostic trouble codes, get Mini VCI which supports all Toyota vehicles.

    You may be right about the cc, however since the OP reported that the battery was drained (which to me means zero bars out of eight bars on the MFD) I would conclude the traction battery also is having a problem.
     
  6. JC91006

    JC91006 Senior Member

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    A bad battery should not allow you to charge it up by sitting for a while and drive to your destination. The OPs description sounds like it's just depleted and charged back up normally. Just what I think based on the info

    The battery is a refurbished battery so a failure again wouldn't be too surprising.
     
  7. uart

    uart Senior Member

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    Could be battery issue, if however the engine is not producing enough power for any reason, then it will drain the battery. So do check the oil and all your fluid levels and make sure that the engine is running smoothly. How long since the plugs were changed?
     
  8. ReisheJ

    ReisheJ New Member

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    Thank you all for your input.

    Renting a car is not an option; we have multiple road trips this summer, so my options are my 2000 Honda Civic (80K) or buying a new car if I do not take the Prius.

    We're not do-it-yourselfers but I do prefer to understand, at least in basic terms, what is or might be wrong when monitoring problems. Since Prius is a different set of systems than the traditional ICE cars I have owned, it's new territory for me.

    My biggest question is how the battery indicator can go from "completely drained" to "sufficiently charged" in such a short time, but I'm curious whether this is a problem with the indicator (already we have a gas gauge that starts blinking "empty" at around 4 gallons, which the dealer told us was "more money than you want to spend" to fix, so the history of reliable indicators has been dodgy), or with the way the battery cells are working together or being managed, rather than the battery actually draining. And of course if the battery did indeed drain fully in normal use, that is a bad thing.

    The local dealer quoted us a price much, much higher than what I read was the Toyota-recommended price for battery replacement when we needed a new traction battery last year (and that was including the $1250 exchange rebate), so we're not terribly trusting of them.
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    When you see the traction battery state of charge indicator show wide swings, that is a leading indicator that the battery is about to fail. The reason it is doing that is that at least one of the 28 modules is weak, and that module will exhibit relatively wide voltage swings as it charges and discharges.

    Perhaps you can relate to this by thinking about your cellphone battery. You have probably noticed that a new battery takes a long time to charge, then it offers a relatively long time during which the phone can be used. As the battery ages, the time needed to discharge to a certain level decreases while the charge time also becomes shorter.

    The traction battery ECU monitors module pair voltages, hence it is keeping track of the voltage produced by each of 14 module pairs. When it sees a big swing in voltage by one module pair, that has an impact upon the overall battery state of charge as measured by the ECU.

    When the voltage swing gets too big, the ECU will log DTC P0A80 which means the traction battery needs to be replaced.
     
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  10. ReisheJ

    ReisheJ New Member

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    Thanks again everyone for your input. For anyone who was curious how it all turned out:

    We signed the papers on a new Prius Prime and will take delivery next week. Yay!

    The battery on the old Prius 2 died on the Parkway on the drive home from the dealer, and it was diagnosed by another Toyota dealership as having a bad module, so GreenTek will be coming out and replacing it. Again. As long as they will keep replacing it, we'll keep that car as a local-only secondary until next year, when we'll know just how much our kid's eventual college bills will pinch the budget. So very glad, though, that it died now and forced the issue, and not at a more inopportune time. Last year the 12-volt battery on this beast died after arrival at our summer vacation destination, Fourth of July weekend.
     
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  11. windstrings

    windstrings Certified Prius Breeder

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    Tell the kids to keep their foot out of it and the battery will do much better.
     
  12. ReisheJ

    ReisheJ New Member

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    Can't blame my teen for this one. She's still permit-only, has only driven with our supervision and doesn't really like driving.
     
  13. jerrymildred

    jerrymildred Senior Member

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    I had not spotted this thread before. Glad you got it sorted out. There sure are a lot of helpful folks here. And congratulations on the new Prime!!
     
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