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Just a simple question about o2 sensors

Discussion in 'Gen 3 Prius Main Forum' started by abdullah arslan, Sep 6, 2024 at 7:01 PM.

  1. abdullah arslan

    abdullah arslan Member

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    I ve also Rav4 other than prius and it threw the code po420. I think due to first o2 sensor not working. I assume the first graph supposed to be up-downs after quick research. Am I right? Screenshot_20240906_185659_Gallery.jpeg

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    #1 abdullah arslan, Sep 6, 2024 at 7:01 PM
  2. Tombukt2

    Tombukt2 Senior Member

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    That code is for the catalyst being below the threshold of performance according to its internal test that it runs every so often If the O2 sensor downstream was bad I think there is a separate code for that so there's always that we may be able to check the O2 sensor with just a regular DVOM ohm meter etc. once the catalyst can't pass the test that the car runs this is the code you get I do believe there are codes for the O2 sensor upstream and downstream that are different
     
    #2 Tombukt2, Sep 6, 2024 at 8:21 PM
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