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Master Warning, Check Engine, and Brake Warning Lights

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Gfunk9981, Apr 5, 2017.

  1. Gfunk9981

    Gfunk9981 New Member

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    Hello,

    I have a Toyota Prius Gen 2. Out of nowhere the master warning light (big red triangle), check engine and brake light came on. It was on for about 40 Km of driving and then went off. Two days ago it came back on and is not going away. The cooling fan for the hybrid is now running constantly and it will not go into HV mode when it is parked (engine keeps running). I checked the voltage on the 12V battery and it is 12.0 pre-start and 14.4 once started. I have posted pictures of the codes. I reset them all last night drove about 10 Km and it was normal again but this morning when I started the car all the lights were back.

    As, well a somewhat related or unrelated problem is with the brakes on the car. When stopping they seam to come in and out a bit. Almost like the ABS wants to kick in and then doesn't (it kicks forward a bit and then goes to normal breaking again).

    Any help would be welcomed. IMG_20170404_215546.jpg IMG_20170404_215546.jpg IMG_20170404_215619.jpg IMG_20170404_215546.jpg IMG_20170404_215619.jpg IMG_20170404_215652.jpg IMG_20170404_215723.jpg IMG_20170404_215814.jpg
     
  2. ericbecky

    ericbecky Hybrid Battery Hero

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    Certainly looks like a hybrid battery issue.
    If Hybrid Battery is not working properly, the regenerative braking system is unable to put energy back into the hybrid battery. So the brakes feel different.

    Start gathering your money for a replacement.
     
  3. bisco

    bisco cookie crumbler

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    clean the cooling fan, 12v looks weak too. how many miles on her?
     
  4. jerrymildred

    jerrymildred Senior Member

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    I'm not saying it isn't the traction battery. It may be going out. But, as @bisco said, 12.0 volts on the aux battery is pretty low with no load and that can give you all sorts of codes.
     
  5. Gfunk9981

    Gfunk9981 New Member

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    It has 150,000 Km. How would I know for sure if it was the 12V battery causing the issues vs the traction battery (without installing a new one)?

    As well, when driving the battery on the display seems to fluctuate between 4/5 bars and full. It is never dropping below 4 bars. Is that any indication of it being 12V vs the traction?

    Will clean the cooling fan and see if that helps.
    Thanks,
    G
     
  6. bisco

    bisco cookie crumbler

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    no way to know. it does seem like the hybrid, but low voltage to the computers can wreak havoc. if you are saying that you don't want to replace the 12v, because if it's the hybrid battery, you're going to dump it, i understand.
     
  7. Gfunk9981

    Gfunk9981 New Member

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    Don't want to dump the car. Just don't want to spend $200 to find out it is the traction battery and then pay another $750 on a refurbished traction battery.
     
  8. bisco

    bisco cookie crumbler

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    if you're going to keep the car, and 12 volts is an accurate cold measurement, you'll be replacing the 12v anyway. any idea how old it is?
     
  9. Gfunk9981

    Gfunk9981 New Member

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    The 12V is at least 4 years old.
     
  10. Samprocat

    Samprocat Active Member

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    Load test your 12v battery....measure of voltage is not the way you should check your battery health

    Posted via the PriusChat mobile app.
     
  11. biglew8

    biglew8 Active Member

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    I have read that as a preventative thing, you should replace the 12V battery every 4-5 years. Older 12V batteries can throw codes at you that might not be true.
     
  12. dolj

    dolj Senior Member

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    This is very subjective and should be taken with a grain of salt, and very much depends on the operating environment and how well the battery has been maintained. I find it hard to throw out a perfectly serviceable battery just because some arbitrary time limit has passed. Test the battery and if it is not up to snuff, replace it.
    It is not really that they are not true, and it is not until you look at what caused the code to come up, you probably find one of the things the computer is not happy about is the low voltage on the 12 V supply.
     
    Raytheeagle likes this.