Which O2 sensor is what?
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This is a discussion on Which O2 sensor is what? within the Tuning: Electronic Engine Management forums, part of the Tech & Modifying & General Repairs category; So what exactly is the front / vs. rear O2 sensor for? I'm thinking the front is for fueling (A/F ...

  1. #1
    Registered User Ingo's Avatar
    Join Date
    Mar 2012
    Colorado Springs, CO

    Which O2 sensor is what?

    So what exactly is the front / vs. rear O2 sensor for?
    I'm thinking the front is for fueling (A/F ratio), the rear is what - for cat efficiency?
    If anyone knows the ins'n'outs, please let me know...
    "this should not be kept secret"
    You can't have everything - where would you put it?

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  3. #2
            MainFrame's Avatar
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    Sep 2002
    Austin, TX
    I Support ClubWRX I Support ClubWRX
    Pretty much what you already said. The front sensor is used for fueling corrections in closed loop.. depending on the year of your car, the rear is only there to throw a code.

  4. #3
    Master Baiter EJ257's Avatar
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    Aug 2007
    On a stream bank somewhere
    I Support ClubWRX
    The rear O2 sensor on the 32-bit ECUs (like your car) is also used in fueling calculations
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