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Prius won't start in the cold

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by ninaherrera, Jan 29, 2021.

  1. ninaherrera

    ninaherrera New Member

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    Hi all,
    I've had my prius for about 2 years, each year as soon as it is getting cold my prius refuses to turn on. I press the start button and all the lights turn on. Last year it would take 2-3 attempts to turn on it is now take 10-12 tries. What I've done: I've done a 12volt battery check (it's all good), I've checked all the battery cells (all good), I've done a tune up, I've replaced the ecm.

    Any suggestions?
     
    #1 ninaherrera, Jan 29, 2021
  2. JC91006

    JC91006 Senior Member

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    how did you check the 12v battery?
     
    #2 JC91006, Jan 30, 2021
  3. sam spade 2

    sam spade 2 Senior Member

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    Exactly what did you do to check it ?
    The odds are overwhelming that it is NOT good.......either the battery itself or a corroded connection.

    You have already spent a fair amount of time and money on a wild guess, while overlooking the obvious.
    The battery might be WAY over 2 years old and that should have been the first thing you did.
     
    #3 sam spade 2, Jan 30, 2021
  4. ninaherrera

    ninaherrera New Member

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    I took it to autozone and they did a battery check and they said it was good.
     
    #4 ninaherrera, Jan 30, 2021
  5. JC91006

    JC91006 Senior Member

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    Without reading the codes on the car, I can't imagine what could happen when it's cold that would prevent the car from starting. Maybe you have a bad brake light switch that acts up when it's cold? If this were to happen, it would have a code.

    I would make sure all your battery connections are tight and there's no corrosion on the wiring. Many Prius cars leak water into the 12v battery area
     
    #5 JC91006, Jan 30, 2021
  6. ninaherrera

    ninaherrera New Member

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    I actually took it to the Toyota dealer and it sat with them for a week and they weren’t able to give me a definitive answer. I just got back from autozone, installed a new 12 volt and still all lights come up as well as the check hybrid system but it doesn’t turn on. I have a 2005 Prius that I’ve never have had an issue with. This 2011 is draining my account.

    Thank you for the suggestion, I’m going to see if I can get a code reader.
     
    #6 ninaherrera, Jan 30, 2021
  7. Grit

    Grit Senior Member

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    Hold down brake pedal, before you press the start button, check to see if the amber light is lit on the start button. If not lit, troubleshoot the sensor behind the brake pedal. If your battery is “good” then the issue is pedal sensor.

    If the amber light stays lit, then check the 12v battery terminals for corrosion and green stuff, clean if needed. Try to wiggle the terminal clamps, if they’re loose just hand tighten. Check the ground cable that connects from the battery to the car chassis also, it may have come loose over time.

    If all of the above checks out fine, check battery manufacture date. It’s typically a circle sticker with month/year- 12/2020. You may have to remove the battery completely to locate the sticker if it’s affixed on the side of the battery. If date is older than 5 years, replace it with a fully charged battery from the shelf.
     
    #7 Grit, Jan 30, 2021
    Last edited: Jan 30, 2021
    JC91006 likes this.
  8. dbstoo

    dbstoo Senior Member

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    How cold is "cold"? I had a 2002 gen 1 model that worked well for years, but on one trip to Lake Tahoe the temperature dropped to near zero. The car needed several attempts to get it to start. The local sealer said that there was a service bulletin that covered it. When I got home my local dealer replaced the ECM $$$$$ and the $20 relay called for by the bulletin. It worked fine from then on.

    There should be trouble codes available via the ODBII connector. That may be the best first avenue of attack.

    Dan
     
    #8 dbstoo, Jan 31, 2021
  9. ninaherrera

    ninaherrera New Member

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    Thank you, it stayed lit. I’ll check cables tomorrow. I greatly appreciate it!
     
    #9 ninaherrera, Jan 31, 2021
  10. ninaherrera

    ninaherrera New Member

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    Not crazy cold, typically when it falls below 40. I’m going to look into that thank you.
     
    #10 ninaherrera, Jan 31, 2021
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