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P0420 and P0430 codes, where to start?

Discussion in 'Technical Chat' started by RobbySkateboard, Mar 18, 2014.

  1. Mar 18, 2014 at 11:19 PM
    #1
    RobbySkateboard

    RobbySkateboard [OP] Well-Known Member

    Joined:
    Feb 21, 2012
    Member:
    #73348
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    104
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    First Name:
    Robby
    Thousand Oaks, Ca
    Vehicle:
    05 4x4 Tacoma TRD Sport DCSB
    I've heard plenty of different things on this forum about these codes ranging from just filling with a higher octane gas and it'll clear itself, to o2 sensors, exhaust leaks and catalytic converters so I'm not sure where to start. I need to get my truck smog checked in the next week and a half and my check engine light is on and reading the p0420 and p0430 codes, I'd like to save some money and fix it myself but I have no idea what to do. Where do I start with these codes? What do I check first and what do I check?
     
  2. Mar 18, 2014 at 11:26 PM
    #2
    koditten

    koditten Well-Known Member

    Joined:
    Sep 8, 2013
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    #112077
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    18,350
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    First Name:
    Kirk
    Central Michigan
    Vehicle:
    04 trd x-cab 4 x 4 3.4l
    Reserected from the dead.
    When I had that code, it was from my cat going south.

    How long have you been running with the check engine light on? With that light on, your engine is running in "open loop". It will be running much richer, thus dumping more unburnt fuel into the cat. With time it will plug the cat. My original problem started with a cracked charcoal cannister(first gen Tacoma).

    Start simple. Loose gas cap, cracked vacuum hoses. Then move to the O2 sensors. Clear codes as you go.
     
  3. Mar 19, 2014 at 2:37 PM
    #3
    esse10

    esse10 Well-Known Member

    Joined:
    Dec 6, 2009
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    #27076
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    356
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    Male
    Texas
    Vehicle:
    05prerunner SR5 DBLCAB
    Pending you don't have a bad sensor or component and just want to pass the smog test for now until you have time to find what contributed to these codes here is what you can do ; Seafoam your intake via a vacuum line, find a utube video online showing how to do that on a Tacoma, only put 5 ounces a little at a time with a tapered end clear hose. Clear all codes by disconnecting the battery for a while, Then just drive the truck hard for two days and all codes should clear and normal. Just realize that it will throw a few other codes when you do this but don't panic they'll clear once you drive it hard for two-three days. Been there done that and worked great on one of my cars that kept throwing the P0420 code. Make sure you check your I/M monitors with an OBDII tester to make sure they're all to "Ok" status before you go get a smog test. good luck man
     

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