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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.







     
    Manfred likes this.
  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
     
    Manfred likes this.
  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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    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.
     
  10. Nov 25, 2019 at 2:21 PM
    #10
    andrewtheadventurer

    andrewtheadventurer Well-Known Member

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    I replaced both sensors in Feb and the truck is throwing a P0430 code again. I have put about 35-40k miles on the truck since Feb.

    Any thoughts?

    I am currently on a trip so Ill probably let it ride till back home.
     
    Manfred likes this.
  11. Jan 29, 2020 at 4:29 PM
    #11
    Zuba987

    Zuba987 Well-Known Member

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    have you found a fix for this yet? My 06 just threw p0430 today and plan to replaces o2 sensor to start.
     
  12. Jan 29, 2020 at 4:34 PM
    #12
    andrewtheadventurer

    andrewtheadventurer Well-Known Member

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    After I headed east away from the pacific, the light went off and it no longer threw the code. Also when the code was thrown earlier this year, i was in FL next to the gulf soooooo it may be something weird with the salt water? no clue
     
  13. Jan 29, 2020 at 4:37 PM
    #13
    Zuba987

    Zuba987 Well-Known Member

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    interesting. I’m driving from PA to UT in May and wonder if it will come up again depending on elevation. Sounds like replacing those two sensors is what I need to do.
     
  14. Jan 29, 2020 at 4:54 PM
    #14
    andrewtheadventurer

    andrewtheadventurer Well-Known Member

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    Yeah my situation is a mystery to me but could hurt to replace. If it helps, I live at 6,000ft and stay around 10,000 ft during the weekends and it has yet to come back on
     
  15. May 6, 2020 at 2:13 PM
    #15
    sam44

    sam44 Member

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    Great thread. I’ve had this code for a while. Sounds like y’all recommend swapping out the O2 sensor before going the cat route?
     
  16. May 6, 2020 at 3:43 PM
    #16
    tammikm

    tammikm Well-Known Member

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    I had this on my 06 as well. Turned out to be leaking at a gasket before the cat. Never has returned since replacing the gasket
     
  17. May 6, 2020 at 9:53 PM
    #17
    EME

    EME Well-Known Member

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    bought mine in june last year, from a GM dealer, 10kms away from dealer light came on, was a cat code, bought a O2 fooler (not spark plug fooler) from Amazon did test cats, and monitor o2 data, all ok that I could see, light has been out ever since...
     
  18. May 23, 2020 at 5:05 AM
    #18
    sam44

    sam44 Member

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    I swapped out my driver’s side downstream O2 sensor, cleared the code, and the code came back after about 300 miles. Any thoughts on next steps? Maybe replace the gasket or fuel filter?
     
  19. Nov 30, 2020 at 9:28 AM
    #19
    RocyTaco

    RocyTaco Active Member

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    I got P0430 the code after using Costco regular gas. The truck was idling for an extended time and it was raining (i.e. humid). The gas mileage for this tank was bad (14 mpg) which is lower than normal for city driving (typically 16 mpg). I guessed bad gas pushed me over the limit. I did a few things after all this. Firstly I reset the code using an OBD scanner and then used Cataclean:

    https://www.amazon.com/gp/product/B0739TGHW8/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1

    I used the 3L bottle in two parts. Each with 1/2 tank of "good" regular gas from Shell. The Truck "felt" better but still got the code back after a few drive cycles.

    Next, I jumped straight to installing a non-fouler on the O2 sensor on the downstream side of the catalytic converter on the driver's side:

    https://www.amazon.com/gp/product/B08D6FDRJ6/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

    $11. Plug and Play. A bit of pain pulling out the O2 sensor but not too bad. Reinstalled using Copper Anti-Seize on all the threads:

    https://www.amazon.com/gp/product/B00HSCN9IS/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

    I also used this O2 Socket to extract and install the sensor:
    https://www.amazon.com/dp/B0009OMYA6

    What surprised me is that not only did the code never return (after 1000+ miles), the gas mileage has considerably improved. It went from 16MPG City (before the Costco gas use) to ~18mpg after all the fixes. I use Fuely and have kept a careful history of my fill-ups. I am happily surprised.

    Frankly, I was just wanting the code to go away and very pleased with the mpg improvement. Engine feels very smooth now. I am not sure which really helped the gas mileage. But P0430 code issue was fixed by the non-fouler for sure.

    I would welcome an explanation on how an anti-fouler on the O2 sensor would improve mileage?
     
    Last edited: Nov 30, 2020
  20. Feb 2, 2021 at 11:30 PM
    #20
    Keith Nguyen

    Keith Nguyen New Member

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    Question, looks like some people double up on these when installing them on the sensor. Did you just use one or two on the drivers rear 02? I wonder if there would be any benefit to having these on both driver and passenger sensors.


     

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