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A/F Ratio Sensor Replacement

Discussion in 'Gen 2 Prius Main Forum' started by MNGoan, Jun 4, 2012.

  1. MNGoan

    MNGoan New Member

    Joined:
    Jan 24, 2012
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    Location:
    La Crescent, MN
    Vehicle:
    2007 Prius
    Model:
    II
    I am getting a P2237 check engine code with an occasional P0031 one. Googling this code gives me the impression that it is the pre catalytic converter sensor that has gone bad. I even probably suspect that it is just the heating element that is not working, since that code does not come back if the check engine light is reset after running the engine for a while. The question that I have is whether the sensor can be replaced without removing inverter, and the like. Dealership is quoting 4.4 hrs time which I suspect would be doing it by the book. Price of sensor is $246 itself, which is pricy. Meanwhile the AC is blowing hot air, which leaves me wondering what do I really want to fix, if anything. Hope this car is not turning out to being a lemon!
     
    #1 MNGoan, Jun 4, 2012
  2. MNGoan

    MNGoan New Member

    Joined:
    Jan 24, 2012
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    Location:
    La Crescent, MN
    Vehicle:
    2007 Prius
    Model:
    II
    Any help, anybody?
     
    #2 MNGoan, Jun 6, 2012
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
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    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    The repair manual requires the inverter to be removed before the air/fuel ratio sensor can be replaced, so it is reasonable for you to assume that step is needed and therefore 4.4 hours does not seem terrible. However if you decide to DIY and can do it without removing the inverter, please post photos showing us how you did it.

    The air conditioning problem is a separate issue, of course, and will probably also be costly to repair, possibly into four-figures. Good luck with that.
     
    #3 Patrick Wong, Jun 6, 2012
    dave77 likes this.
  4. 13Plug

    13Plug Active Member

    Joined:
    Apr 7, 2008
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    Vehicle:
    2013 Prius Plug-in
    Model:
    Plug-in Base
    Well I don't know if I can help much, but my 08 had a P0031 and the dealer replaced the front A/F ratio sensor under warranty. I don't know how much time it took, but replacing it fixed the code. And that was like 3 years ago.

    Whatever you do, make sure you replace it with an OEM sensor!
     
    #4 13Plug, Jun 6, 2012
  5. Keyslammer

    Keyslammer Junior Member

    Joined:
    Oct 21, 2015
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    Location:
    San Luis Obispo County, CA
    Vehicle:
    2008 Prius
    Model:
    II
    The "easiest" way to do this is to remove the wipers, plastic leaf catcher, then the wiper motor. Then pop out a few of the harness clips on the driver side of the harness to swing the tray over on top of the inverter. This gives you "relatively" clean access to the A/F sensor. I also removed the 10mm bolt holding the mating connector mount, so that I could manipulate the connection around. This is all pretty straight-forward...but time-consuming. You will still need the special A/F sensor socket adapter that has the slit to go over the wire harness.
     
    #5 Keyslammer, Feb 18, 2019
  6. gptoyz

    gptoyz Junior Member

    Joined:
    Jan 9, 2010
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    Location:
    los altos
    Vehicle:
    2010 Prius
    Model:
    N/A
    Yes this is the best method to get to the wideband. For the special tool, grab a very thin wall deep socket and DIY slot it with a hack saw and file the edges so they don't damage the wire
     
    #6 gptoyz, Feb 19, 2019
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