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Help me use my scangauge to diagnose P0420 code

Discussion in '2nd Gen. Tacomas (2005-2015)' started by joes06tacoma, Feb 17, 2013.

  1. Feb 17, 2013 at 6:16 PM
    #1
    joes06tacoma

    joes06tacoma [OP] Well-Known Member

    Joined:
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    Member:
    #28588
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    First Name:
    Joe
    Central Coast, CA
    Vehicle:
    06 4x4 Off Road Access Cab v6 6spd
    LEER Shell with dome lights operated with 3 way switches, aux backup lights with relay and 3 position switch, modified wiring to compass/temp display and clock to include switch that disables dimming function (poor man's DRL solution), Scan Gauge 2
    I have a P0420 code (catalyst inefficiency code, bank one). I cleared it once and it came back. Truck runs perfect. No other concerns.

    I went on Scanguage's website and found XGauge codes to read air/fuel ratio and O2 sensors. I tried all the codes, and not all of them work. If I understand correctly, the ones I have programmed and working now are A/F ratio for bank 1, A/F ratio for bank 2, number 2 sensor for bank 1, number 2 sensor for bank 2. As far as I can tell, sensor 2 is the downstream sensor after the cat.

    Comparing bank 1 and bank 2 readings, I see no differences in behavior between the two banks.

    The truck has 64K miles on it. Seems pretty lame to have a CAT die on me. Hoping it's a sensor issue, but sounds like that doesn't happen too often from reading on here.

    Still have about 9 months and 16K left on the catalytic converter warranty. Its temping to go down to the dealer and drop it off, but I know nothing about the quality of the staff down there, and I fear being told that I have a CAT bad and need to replace the sensors too because they are damaged, etc, etc. I would rather be educated on what sensor readings would indicate what first. I want to replace only what is needed.

    Thanks for any help that you can offer.

    Anybody switched O2 sensors side to side and see if the code moves to the other bank?

    Which side is bank 1?
     
  2. Feb 17, 2013 at 6:21 PM
    #2
    DoorDing

    DoorDing Someone was there .

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    Seems like a good place to start.

    Do you have a specific reason not to trust that dealership? If you do, try another one. Whatever you do, definitely don't allow your CC warranty to expire before fixing this.
     
  3. Feb 17, 2013 at 8:30 PM
    #3
    joes06tacoma

    joes06tacoma [OP] Well-Known Member

    Joined:
    Jan 1, 2010
    Member:
    #28588
    Messages:
    3,061
    Gender:
    Male
    First Name:
    Joe
    Central Coast, CA
    Vehicle:
    06 4x4 Off Road Access Cab v6 6spd
    LEER Shell with dome lights operated with 3 way switches, aux backup lights with relay and 3 position switch, modified wiring to compass/temp display and clock to include switch that disables dimming function (poor man's DRL solution), Scan Gauge 2
    Yeah, I should take it in there and see what they say. Just trying to avoid the add on of two O2 sensors that I do not need, just to get the CAT warrantied.
     
  4. Feb 17, 2013 at 8:35 PM
    #4
    DoorDing

    DoorDing Someone was there .

    Joined:
    Sep 7, 2012
    Member:
    #86445
    Messages:
    26,025
    Gender:
    Male
    bee keeper
    Vehicle:
    2012 DCSB Off-Road 4WD
    I don't know why you can't have them give you an estimate before any work. If you decide to do any of the work yourself, I don't think it'll be a problem as long as you get it back w/o too many miles for a cat replacement.
     
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