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2010 Prius won’t start with key fob!

Discussion in 'Gen 3 Prius Technical Discussion' started by JaredJn, Apr 5, 2021.

  1. JaredJn

    JaredJn New Member

    Joined:
    Apr 5, 2021
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    Location:
    East Brunswick, NJ
    Vehicle:
    2010 Prius
    Model:
    Four
    Hey everyone, I’ve been coming here for awhile and just never made an account but here it is. I’m having an issue that I can’t seem to understand.

    Bought my Prius used with 86k miles about a year ago and they only gave me one key fob. The only thing I’ve replaced was the manual key since the bottom part broke off of my last one.

    Either way, I’ve noticed my key slowly dying for a month or two and neglected to put in the new battery. Today I went outside to start the car by holding the key fob to the start button and the system keeps telling me to depress the brake and use the key fob, which I’m doing.

    Does this mean the key fob is completely dead and the car can’t pick it up at all or has my key somehow lost the programming to the car?
     
    #1 JaredJn, Apr 5, 2021
  2. ForestBeekeeper

    ForestBeekeeper Active Member

    Joined:
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    Location:
    Maine
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    This has happened to us a few times. The 12vdc battery in your car has died. Maybe the trunk was left over-night unlatched, so the interior light was on all night. Something caused the battery to run down.
     
    #2 ForestBeekeeper, Apr 5, 2021
    bisco likes this.
  3. bisco

    bisco cookie crumbler

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    boston
    Vehicle:
    2012 Prius Plug-in
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    Plug-in Base
    the fob uses an rfid chip, so no battery is needed. it is possible that you need a new fob, try cleaning it.

    if you get it working, get a second asap
     
    #3 bisco, Apr 5, 2021
    JaredJn likes this.
  4. JaredJn

    JaredJn New Member

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    Apr 5, 2021
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    Location:
    East Brunswick, NJ
    Vehicle:
    2010 Prius
    Model:
    Four
    But everything else in the car is fine, dashboard and everything. What else does this 12vdc battery control so I can rule out whether it is that or not?
     
    #4 JaredJn, Apr 5, 2021
  5. JaredJn

    JaredJn New Member

    Joined:
    Apr 5, 2021
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    Location:
    East Brunswick, NJ
    Vehicle:
    2010 Prius
    Model:
    Four
    I’ve opened it and everything looks clean and good instead. Still nothing. I’m going to try and get another battery and in the meantime save up for another fob :unsure:. I know they can cost around $400 or so, so I’m not looking forward to it haha.
     
    #5 JaredJn, Apr 5, 2021
    bisco likes this.
  6. ASRDogman

    ASRDogman Senior Member

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    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Two
    There is a battery in the key fob, "1632".
    I'm going to order two later. I got the message yesterday that it was weak.
    But it's been fine the last 8 or 9 times. So I'm using my spare one and will see how long that
    battery lasts..
     
    #6 ASRDogman, Apr 5, 2021
  7. Ed Beaty

    Ed Beaty Active Member

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    Location:
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    Vehicle:
    2010 Prius
    Model:
    IV
    "There is a battery in the key fob, "1632".
    Bisco knows that. What he means: even if the fob battery is dead or disabled, the RFID chip, when held against the Power button, will enable recognition. Y'know, that's WHY the manual tells you to DO that when you have a starting issue. Right?
     
    #7 Ed Beaty, Apr 5, 2021
  8. JaredJn

    JaredJn New Member

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    Apr 5, 2021
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    Location:
    East Brunswick, NJ
    Vehicle:
    2010 Prius
    Model:
    Four
    That’s what I wanted to clarify. Btw, just to update everyone I purchased a new battery for the key and replaced it. Everything working as usual. I’m still curious why the RFID chip didn’t work though...
     
    #8 JaredJn, Apr 5, 2021
  9. Ed Beaty

    Ed Beaty Active Member

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    Location:
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    Vehicle:
    2010 Prius
    Model:
    IV
    THIS (from Torque) may shed some light. Perhaps you didn't actually push on the power button with the dead fob as suggested in the article.
     
    #9 Ed Beaty, Apr 6, 2021
  10. Tbkilb01

    Tbkilb01 Active Member

    Joined:
    Jul 12, 2016
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    Location:
    Louisiana
    Vehicle:
    2011 Prius
    Model:
    IV
    Happened to me.
    I Changed batteries in both FOBS. No change ...Seemed Prius would shut down SKS. Driver nor passenger door worked as usual. KEY NOT RECOGNIZED popped (screamed) on HUD display as I closed doors. Thought of My 92 previa ...I had to turn key backwards twice to unlock backdoor and hatch. So...I used PRIUS metal key in PRIUS door keyhole and pushed backwards twice and the forward twice just for funzees and now everything works fine. Both front doors and even hatch unlock as FOB nears. No more HUD warnings... shear luck or built in? Just glad it works now.
     
    #10 Tbkilb01, Dec 29, 2021
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