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Gen2 o2 sensor problems

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Jonny Morrow, Sep 9, 2018.

  1. Jonny Morrow

    Jonny Morrow Junior Member

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    Hey guys. Got a 2006 with 166k throwing a P0420. Wanna check all I can before replacing the cat. I'm in techstream and I just would like to know if my upstream sensor values are normal. Tough to find normal value info on the internet.

    My upstream is at 5v while the ICE is off and hovers around 3.3v while driving. It seems 3.3v is normal while driving but is 5v at rest normal?

    Downstream is all over the map from .1 to .9. I realize this probably means the cat isn't doing its job.

    Anything else I can try before I throw $2000 at the dealer on a car that is barely worth that? Thanks guys!
     
    #1 Jonny Morrow, Sep 9, 2018
  2. audiodave

    audiodave Active Member

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    You must be in California. Burning much oil? I had a cat sent to a friend in Texas than to me for installation. Not legal but two tests and neither looked under the car. Passed both times.

    Posted via the PriusChat mobile app.
     
    #2 audiodave, Sep 9, 2018
  3. padroo

    padroo Senior Member

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    How much oil do you use?
     
    #3 padroo, Sep 9, 2018
  4. Jonny Morrow

    Jonny Morrow Junior Member

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    She doesn’t burn oil. I change the oil myself and never see it drop. We bought the car used and it runs amazingly well. If it’s the cat it’s just from old age I guess.

    Yes I am very unfortunately in CA. Might give the 49 state cat a try and hope they don’t look.
     
    #4 Jonny Morrow, Sep 9, 2018
  5. Raytheeagle

    Raytheeagle Senior Member

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    Where in CA are you located?

    If you reveal the location, might help in dealing with the next steps.
     
    #5 Raytheeagle, Sep 9, 2018
  6. Jonny Morrow

    Jonny Morrow Junior Member

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    Orange County
     
    #6 Jonny Morrow, Sep 9, 2018
    Raytheeagle likes this.
  7. Raytheeagle

    Raytheeagle Senior Member

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    Some members down south might be able to assist with shop choices.

    I’d try the o2 sensors before investing in the cat.

    When is your inspection do?

    How long does the check engine light stay off once it is reset?
     
    #7 Raytheeagle, Sep 9, 2018
  8. johnjohnchu

    johnjohnchu Active Member

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    Sensor info enclosed
     

    Attached Files:

    #8 johnjohnchu, Sep 9, 2018
  9. Jonny Morrow

    Jonny Morrow Junior Member

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    Don’t want to throw parts at it hence why I’m looking for normal o2 voltage values. Looking for troubleshooting help, not cat replacement help. I can find a cat if I need to.

    Like my post says, let me know if anyone has normal o2 sensor voltage values for a 2006. Upstream and downstream.
     
    #9 Jonny Morrow, Sep 9, 2018
  10. Jonny Morrow

    Jonny Morrow Junior Member

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    Thanks for the PDF JohnJohn.
     
    #10 Jonny Morrow, Sep 9, 2018
  11. audiodave

    audiodave Active Member

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    Let us know us now if the numbers are off. I replaced my cat on a 04 with 225.000 on the clock.

    Posted via the PriusChat mobile app.
     
    #11 audiodave, Sep 9, 2018
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