Battery problem?

Discussion in 'Gen 3 Prius Technical Discussion' started by Dawst, Jun 10, 2019 at 10:29 AM.

  1. Dawst

    Dawst New Member

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    Heya! I've come across a new problem that I've never experienced with before after driving the Prius for 2 years.

    Pressing the power button twice to get the engine running. The problem first occurred when I would normally start the car but rather the engine starting, the power button lit orange. Turning off the car and pressing the power button again, the orange light would disappear and the engine would start running.

    That's what it's been most of the time for a few days until at one point, the car wouldn't shift gears and the message "Low traction battery" would pop up and the battery bar would be at 1 or 2 bars. Fortunately, a miracle happened after restarting the car again and again until the engine started to run and was able to get home to investigate the problem.

    After awhile of not driving, the car wouldn't run and the "Low traction battery" message would pop up again.
    I've read somewhere that it could actually be the 12V battery that's causing the issue. I bought a voltmeter to test it out and it read below 12V. Something around 11.50?I tried disconnecting the 12V battery for 5 minutes and voila! The car started to run again (still the same problem of having to press the button twice). Thought it was a bad battery (I have an Optima battery FYI) and tested the voltage today and got a reading of 12.37V before starting the car and 14.34V after starting the car.

    Something usual happened where now, if I'm lucky, I can just press the button once for the car to start.

    I was wondering if any of you guys have encountered this problem and what you did you solve it! Thank you so much for reading this.
     
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  2. Sajish

    Sajish New Member

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    Hey there......
    i have a problem and wondering whether any body could figure it out. My prius would not start. I took it to toyota and they checked the battery and said it was ok. They did a drain test and said there was no drainage. They returned the car and said every thing was fine. The next day the car would not start. I jump started it. What do you think is the problem. Any suggestions would be highly appreciated
     
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  3. FuelMiser

    FuelMiser Active Member

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    The way it should work is: press the brake pedal and the power button lights up green indicating there is a good connection between the car and the fob. An orange LED when pressing the brake pedal indicates something wrong with the power-on communication between the car and the fob. One thing you could try is place the fob over the orange LED and see if it goes green. This is the backup procedure to make the car ready to start. A bad communication between the car and the fob could be either a low battery in the fob, or a low 12 Volt battery in the car. Beyond that, it could be a damaged fob or damaged antenna in the car. I guess it could also be a bad brake pedal switch--you could check to see if your brake lights illuminate when you press the brake pedal.
     
  4. ASRDogman

    ASRDogman Senior Member

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    11.5 is too low. 14.34v means it's getting a charge, but not taking it. You need a battery.
    That's your first step. Which will probably resolve the low traction battery light.
     
  5. sam spade 2

    sam spade 2 Senior Member

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    You should believe what the car is trying to tell you.......to a point.

    Likely that your HV/traction/hybrid battery is getting weak.
    You should take it to a qualified shop (probably Toyota) for a test.

    It is also possible that the 12 V battery is low......as that sometimes causes false failure indications on other things.

    The problem has NOT fixed itself. It will be back. And the next time it might not start at all.
     
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  6. sam spade 2

    sam spade 2 Senior Member

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    First, it is not nice to inject your different problem into someone elses thread. It just causes confusion.

    Then, it is likely that your 12 V battery is going bad. Sometimes even the best shops have trouble testing to find that out.
     
  7. royrose

    royrose Active Member

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    If you get an OBDII bluetooth enabled dongle (to plug into the diagnostic port under your dash), you can use apps to test the health of your hybrid battery. I use the Dr. Prius App which shows the charge of each module and does a battery stress test to estimate the charge capacity of the battery overall. It does cost something like $8.95 to use on one vehicle, can then do repeated tests as needed. On my 2010 with 96,000 miles, the test showed 83% capacity which is quite good.

    Info on the Dr. Prius App with recommendation on which OBDII dongle to buy: Hybrid battery diagnostic and repair tool for Toyota and Lexus

    How old is your 12v battery and how many miles on your 2010 Prius?
     
    #7 royrose, Jun 12, 2019 at 10:26 AM
    Last edited: Jun 12, 2019 at 10:33 AM
  8. Morris Jason

    Morris Jason New Member

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    Mine had same issue and today it stalled and now can't start the engine what should I do ?
     
  9. bisco

    bisco cookie crumbler

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    replace the 12v. then put a reader on it for codes
     
  10. Dawst

    Dawst New Member

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    I don't think I've tried holding the fob against the power button so I'll look into that next time.
    I recently changed that battery for the fob and as I was trying to turn on the car every time, I'd see the brake lights illuminate from the reflection of the car beside me. Probably it is the 12V battery. Though I got it checked at O Reilly's and told me the battery is good.
     
  11. Dawst

    Dawst New Member

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    What would you say is a healthy voltage? I head over to O Reilly's to check out the battery and was told that it was healthy. I was debating on getting the battery but was worried whether it'd make a difference.
     
  12. Dawst

    Dawst New Member

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    Yeah that's on me. Thinking of getting a mobile installation done from Hometown Hybrids. They would check the car to see whether or not they're able to install a new battery. Really wanted to get one from 2k1toaster but worried that even with the new battery, the car wouldn't work. I'm probably just overthinking it.
     
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  13. ASRDogman

    ASRDogman Senior Member

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    I believe the lowest is 12.4. It's a fussy battery. How old is it?
    You can do a search here to find better info on the 12v Battery.
    But if it's 11.x, it is too low.
     
  14. sam spade 2

    sam spade 2 Senior Member

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    Have it towed to a qualified Toyota shop.
     
  15. sam spade 2

    sam spade 2 Senior Member

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    In general, if it is just sitting there and you are SURE that nothing is powered up.......below 12.3 is suspect, below 12.0 is bad.....but it first needs a good charge and a load test. If it is over 4 years old, just replace it.
     
  16. bisco

    bisco cookie crumbler

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    hometown hybrids has an excellent reputation here
     
  17. Dawst

    Dawst New Member

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    I'll have to look into that! Thanks! The battery states 6/15 although I bought a refurbished optima battery around late 2017. Bought another battery so going to have to check to see if the 12V help attribute to the problem.
     
  18. Dawst

    Dawst New Member

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    Will report back once I get the battery from Amazon.


    Had the refurbished since late 2017 but the sticker says 6/15.


    Good to hear. Do you know what the reputation is like for the other companies like green bean batteries and green auto tec? Thinking of going with just the mobile installations for convenience.
     
  19. bisco

    bisco cookie crumbler

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    they are hit or miss. some have had decent luck, others not. talk to matt at hometown, he'll give you the truth on rebuilt batteries
     
  20. lucaspiller

    lucaspiller Junior Member

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    @Dawst I had similar issues starting when my 12v died a couple of years ago, so I'd wager that's the issue. Once I got it in READY mode it worked fine though.
     
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