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Prius Smart Key Causing Check Engine Light

Discussion in 'Gen 2 Prius Main Forum' started by Jordan Duran, Mar 22, 2017.

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  1. Jordan Duran

    Jordan Duran New Member

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    The CEL in my 2009 Prius is on for the firs time since I've owned it and of course it's registration/inspection time. I took it to the local repair shop and had them read the code. I was told that my smart key was causing it and that it needed to be taken to the dealership for a replacement fob. I've never heard of a key throwing a code and in all my web searches on the subject I haven't come up with any examples of this happening to anyone else. This leads me to believe that perhaps the tech was mistaken in his interpretation of the code. Anyone have any thoughts?
     
    #1 Jordan Duran, Mar 22, 2017
  2. JC91006

    JC91006 Senior Member

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    I hope you didn't have to pay that tech. Check engine lights are usually emissions related problems
     
    #2 JC91006, Mar 22, 2017
  3. Jordan Duran

    Jordan Duran New Member

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    No It was free.
     
    #3 Jordan Duran, Mar 22, 2017
  4. DonDNH

    DonDNH Senior Member

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    Ask the local repair shop for the code they pulled, they may have either misread it or misinterpreted what the code meant. Some ODB readers don't report correctly for the Prius.
     
    #4 DonDNH, Mar 22, 2017
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  5. Jordan Duran

    Jordan Duran New Member

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    Yes, you're right about the emissions, only in this case he said it was the key fob.
    The tech clarified that it was a code related to the vehicle's immobilizer system but didn't recall the exact code. Can anyone direct me on troubleshooting immobilizer system trouble?
     
    #5 Jordan Duran, Mar 22, 2017
  6. JC91006

    JC91006 Senior Member

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    are you sure the light you have on is a "check engine" light? Can you post a picture? An immobilizer light has a key logo
     
    #6 JC91006, Mar 22, 2017
  7. DonDNH

    DonDNH Senior Member

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    I would replace the battery in the key fob and then test the voltage of the 12V battery. Many owners have reported odd problems caused by a failing 12V.
     
    #7 DonDNH, Mar 22, 2017
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  8. Jordan Duran

    Jordan Duran New Member

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    Yes, It's a check engine light. The immobilizer light blinks when the car is off.
     
    #8 Jordan Duran, Mar 22, 2017
  9. JC91006

    JC91006 Senior Member

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    check engine light is not related to immobolizer unit
     
    #9 JC91006, Mar 22, 2017
  10. bisco

    bisco cookie crumbler

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    is the gas cap tight?
     
    #10 bisco, Mar 22, 2017
  11. ♡myPeeus

    ♡myPeeus Junior Member

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    Check the battery in your smart key. That was my issue when this occured

    Posted via the PriusChat mobile app.
     
    #11 ♡myPeeus, Mar 22, 2017
  12. TampaPrius.com

    TampaPrius.com Active Member

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    95 % of all CEL lights I scan are
    P1121 Coolant control valve or
    P0420 Bad Catalytic converter
     
    #12 TampaPrius.com, Mar 22, 2017
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