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P0430 Code: Catalyst System Efficiency Below Threshold (Bank 2)

Discussion in '2nd Gen. Tacomas (2005-2015)' started by qnyla, Sep 13, 2015.

  1. Sep 13, 2015 at 11:19 AM
    #1
    qnyla

    qnyla [OP] Well-Known Member

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    I have started getting a P0430 code on my 2006 4.0L. It is occuring with increasing frequency over the last 1000 miles or so and interestingly seems to occur most often when it is humid or raining. I have been monitoring codes and resetting the CEL using an Ultragauge.
    I hope the catalytic converter is not bad. I am going to start small and work my way up. Starting with the O2 sensor.

    P0430 Bank 2 is driver's side: Bank 2 is side of engine w/#2 cylinder, which is driver's side. Since I am getting only P0430 and not also P0420 (Bank 1 passenger side) I suspect a O2 sensor or air/fuel ratio sensor on the drivers side, not something that would be common to both sides such as dirty MAF sensor, fuel tank cap, fuel pump, fuel filter, etc.

    At 394k miles all these original sensors should be replaced anyway, so I decided to start with changing the O2 sensors on both sides.

    I used:
    Denso 234-4260 (right side = passenger side)
    Denso 234-4261 (left side = drivers side)

    and bought them from Amazon:

    http://www.amazon.com/gp/product/B00199FBQY?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01

    http://www.amazon.com/gp/product/B0016NBBQW?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

    If this does not fix the issue, the next step will be the more expensive upstream air/fuel ratio sensor.

    Results:

    So far, the result is no additional P0430 codes. Keeping my fingers crossed.







     
  2. Sep 14, 2015 at 5:07 AM
    #2
    johng34

    johng34 Member

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    qnyla,
    Thanks for the info. I've also got an 06 4.0L, but have 5sp Auto. I just bought it a year ago with 110k on it. Around 115k it's been putting on the check engine light. Can't recall the code but the dealer originally (6 months ago) said I needed 2 catalytic converters, which to me is crazy given the relatively low mileage. It just went in for the frame change and now they say I need the fuel/air sensor and one cat. I'm not believing either till I diagnose it myself with an oscilloscope.
    Please keep us updated on whether or not your o2 changes fix your issue permanently.
    Also, where did you get the o2 socket? Offhand do you know the size and how much you paid for it?
    I'd read that the 06 doesn't have a fuel filter, did you add one? I'm seriously considering it.

    Thanks,
    JG
    Hollis, NH
     
  3. Sep 14, 2015 at 5:29 AM
    #3
    qnyla

    qnyla [OP] Well-Known Member

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  4. Sep 14, 2015 at 6:31 AM
    #4
    Torspd

    Torspd Tor-nication

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    If you want to "add" a removable fuel filter, you'll need to do a fuel pump upgrade kit. That in itself is still cheaper than replacing the OEM fuel filter. By about ~$300. Plus then your can easily replace the fuel filter for about ~$15 from Napa.

    At 100k miles +, I can promise you that your fuel filter needs to be replaced. Your truck will thank you.
     
  5. Sep 14, 2015 at 7:20 AM
    #5
    Muy Grande

    Muy Grande Well-Known Member

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    Yup! I got those codes......changed out all 4 sensors with Denson bought them from Rock Audo (cheapest place on line) and also replaced the Fuel Pump Assembly. That spark plug socket is a life saver and a must have for this job. It gets a little tight for the upstream sensors and that heat shield will release some particles so wear something to protect your eyes.
     
    Jaab likes this.
  6. Dec 20, 2015 at 6:13 AM
    #6
    Jaab

    Jaab Well-Known Member

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    OME 887, Dakars ARB bull Bar, M8000 winch,ABS mod, Locker mod, fog lights anytime mod, COMFY BMW sport seats, tweaked Airbag emulator,
    I have been through hell and back with 0430 and 0420 codes and have figured out what I needed to do...quite the learning curve.
    First, I went to a reputable aftermarket cat. cost about $450 Canadian for the two...a hell of a lot cheaper that Toyotas. I e-tested. Failed.
    Then bought all 4 o2 sensors. E-tested. failed. Then I researched the living crap out of everything, went to my Toyota dealer to ask their thoughts and learned a few things.
    Using these figures as mythical ones merely for illustration...but hopefully the point will get across.

    Toyota Cats....90-95% efficient.
    Aftermarket Cats....80-85% efficient.

    The difference is enough to send the Toyota ECM into fits, spurting out codes of cat failure.

    So, amazingly enough, Toyota gave me the same fix I read about elsewhere.


    SPARK PLUG ANTIFOULERS. $6.00 (18mm, I believe)

    Take the antifouler and bore it out to a minimum of 1/2".....uninstall the downstream o2 sensor, reinstall the o2 sensor into the anifouler, then screw the assembly into the o2 bung....tighten, no silicone, just the supplied crush washers....reset everything, go through a complete drive cycle and baddaboom! CODES GONE!

    This took me a month of resetting, waiting for parts, installing and CRAP. The worst is going through drive-cycles...time consuming.

    DO NOT bore less than 1/2". It WILL set off the code again. Also...if for some strange reason this doesn't work...do not panic...STACK two antifoulers!!

    I really hope this saves a bit of time and worry for some...I live in an emission tested area and it sucks when you can't get those codes gone!


    now...amusingly enough, I am about to go to the garage and bore out another set for my buddy with the same issue. :D
     
  7. Dec 20, 2015 at 9:02 AM
    #7
    tinker2

    tinker2 Well-Known Member

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    @Jaab, you're boring out the inside of the Antifowler so the sensor portion will go inside when threaded into it ? And are you doing this to all 4 or just the down stream 2 sensors ?
     
  8. Dec 20, 2015 at 11:13 AM
    #8
    Jaab

    Jaab Well-Known Member

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  9. Feb 11, 2019 at 3:32 PM
    #9
    andrewtheadventurer

    andrewtheadventurer Well-Known Member

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    I think I have a Tacoma.
    How many miles did it take for the light to turn off?

    I just changed my O2 sensor because i was getting the same error.

    I also bought the socket but used a 7/8 closed ended wrench because of the tight space. Hope this helps people.
     

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