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P2196 - how to tell which O2 sensor? (2010 Prius)

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by wsalopek, Jun 28, 2021.

  1. wsalopek

    wsalopek Junior Member

    Joined:
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    Location:
    Morro Bay, CA
    Vehicle:
    2015 Prius Plug-in
    Model:
    II
    Hi folks...

    This is the exact text from the OBD-II reader (Autozone):

    P2196 - Oxygen signal sensor biased / stuck rich bank 1 sensor 1

    So is that the "rear lower" or "front" (as described by the website description in the below image)? Or is the "air/fuel" sensor (if one of those even exists)?

    I see the "upstream" sensor, which I assume is the same as the "front", needs a special tool, etc, and probably something I'd leave to the shop:



    I also saw mention that the 2010 Prius only has ONE "O2" sensor, and it's actually the aforementioned "air/fuel" sensor? Is that true?

    Local shop wants about $400 for the job...$144 labor (1+15 hours), so about $250 for the part, but luckily, they will use "OEM" parts from me to do the job, and I see the prices below, from https://www.oemgenuineparts.com/, are priced much lower. That said there are O2 sensors on eBay for $40, which I'd be glad to try if the sensors are easy to swap out.

    Thanks...

    P.S. I should mention that this code popped up right after we had a JDM engine installed (at 237k miles), and the car had been using some coolant for several months...we had heard the catalytic converter might go bad after that kind of thing? But P2196 is the only code.

    O2 sensor.jpg
     
    #1 wsalopek, Jun 28, 2021
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Vehicle:
    2010 Prius
    Model:
    Touring
    Both air/fuel and O2 are id'd in this Repair Manual excerpt:
     

    Attached Files:

    #2 Mendel Leisk, Jun 28, 2021
  3. wsalopek

    wsalopek Junior Member

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    2015 Prius Plug-in
    Model:
    II
    Thanks very much Mendel. So it seems to be saying it's the "air-fuel ratio sensor", as opposed to an "oxygen" sensor. That said, part manufacturers still seem to call it an oxygen sensor (if this is the right part):

    KAX 234-9052 Oxygen Sensor 234-9056 250-54006 Heated O2 Sensor Upstream Sensor 1 Original Equipment Replacement 1Pcs
    by ZonCar:
     
    #3 wsalopek, Jun 28, 2021
  4. ChapmanF

    ChapmanF Senior Member

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    Model:
    IV
    That's a good illustration of why it's rarely useful to try to make decisions from the text "fortune cookies" shown for codes on scanners, especially generic ones, or generic code lists or internet searches.

    If you turn to P2196 in the repair manual (more info), your questions get answered pretty well right on the first page:

    P2196.png

    ... plus you get 24 more pages in that section telling you what can happen to set that code and what tests you can do to figure what the cause was in your car, and what to do about it.
     
    #4 ChapmanF, Jun 28, 2021
    Mendel Leisk likes this.
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    2010 Prius
    Model:
    Touring
    Here's that:
     

    Attached Files:

    #5 Mendel Leisk, Jun 29, 2021
  6. JCEze

    JCEze Junior Member

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    III
    Did the thread originator ever find the root cause of the code?? I have the exact same situation (replaced engine in a 2010 and got this code). Thanks for the response in advance!!
     
    #6 JCEze, Dec 27, 2021
  7. ChapmanF

    ChapmanF Senior Member

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    I see that Mendel posted the code details and troubleshooting steps from the repair manual in post #5. The best way for you to find what's causing the code in your car will be to follow those, just as it was the best way for the thread originator to find what was causing it in his car.
     
    #7 ChapmanF, Dec 27, 2021
  8. Kashif1

    Kashif1 New Member

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    Location:
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    Vehicle:
    2010 Prius
    Model:
    ----UK----
    Hello hope you all doing great need your help I have been to mechanic and he hasn't been able to diagnose exactly the problem
    I am getting these 2 codes
    P0420 (catalyst system efficiency below threshol Bank 1)
    Mec asked me to change fuel ratio sensor (one in engine compartment)
    After changing that I start getting another code
    P2196 (O2 sensor signal biased stuck rich bank 1 sensor 1)

    Should I change the sensor at the bottom by exhaust ?
     
    #8 Kashif1, Jun 15, 2023
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