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02 sensor Air fuel sensor help

Discussion in '1st Gen. Tacomas (1995-2004)' started by kasemo223, Jan 31, 2017.

  1. Jan 31, 2017 at 2:08 AM
    #1
    kasemo223

    kasemo223 [OP] Member

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    sorry i know alot of these posts have been made but the more i look at them the more confused i get, i recently have had a check engine light come on for my 2000 tacoma v6 (manual) code was P0420 friend sent a chart and said it could be A/F sensor (bank 1 sensor 1) Heated oxygen sensor (bank 1 sensor 2) or my cat, i figured i would start with my sensors but like i said the more i try to look those 2 up i get confused on how many and what one to buy some people say i need a air fuel sensor or just 2 02 sensors, i thought i had the part number for them but when i went to purchase on Amazon it said it would not fit my truck, so can anyone please help link me those 2 parts for my truck please? sorry if i left something out
     
    Last edited: Jan 31, 2017
  2. Jan 31, 2017 at 3:24 AM
    #2
    Wyoming09

    Wyoming09 Well-Known Member

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    Super Springs
    Now the PO420 Code just says what ever the difference is between your Front and Rear Sensors The ECM is not seeing enough of a change

    This can be from a leaking exhaust gasket

    A bad most often rear sensor

    A Bad Cat

    Wiring from the Sensor To the ECM or the ECM

    Now do you know Just what Emissions package you have Tacoma`s with the California package are all over the country !!

    Now if you have the California Emissions The front one (upstream) is A Air Fuel Sensor Denso # 234-9003

    The rear ( Down Stream) is Denso 234-4189 O2 Sensor

    Only the California Emissions Package has the Air Fuel Sensor upstream

    This is other then California Below

    If you have the Federal Package Front (upstream) Denso # 234-4161

    Rear (downstream) Denso # 234-4154

    If I recall the only difference between these two is the length of the pig tail on the Sensor

    Hope this helps
     
  3. Jan 31, 2017 at 3:32 AM
    #3
    kasemo223

    kasemo223 [OP] Member

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  4. Jan 31, 2017 at 3:40 AM
    #4
    Wyoming09

    Wyoming09 Well-Known Member

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    Pretty easy to tell Living where you do

    California will have two cats

    Yes then you would need the Sensors you have listed above .
     
  5. Jan 31, 2017 at 3:45 AM
    #5
    kasemo223

    kasemo223 [OP] Member

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    i wish i could remember as iv only been under the truck for oil change and taking off the driveline to take in to replace the u-joint, thank you so much for quick response i will look tomorrow as it is 3:40 am atm >.> i will look tommorow and thank you so much for quick responses!!! you are a god amongst men
     
  6. Feb 1, 2017 at 4:31 PM
    #6
    kasemo223

    kasemo223 [OP] Member

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    ok now im back i took pictures of both these are they both cats? the smaller one is closer towards my passenger tire and the longer one is futher back... and beyond that there is the big muffler so does that mean these two are both cats?, sorry i cant even find this in my manual

    Attach19268_20170201_192428.jpg
    Attach19267_20170201_192414.jpg
     
  7. Feb 1, 2017 at 4:42 PM
    #7
    98 Tacoma 4x4

    98 Tacoma 4x4 Well-Known Member

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    Looks like you have two catalytic converters.
     
  8. Feb 1, 2017 at 4:43 PM
    #8
    kasemo223

    kasemo223 [OP] Member

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    sweet thank you for quick response ! i kno what to order now woot!
     
  9. Feb 1, 2017 at 4:45 PM
    #9
    98 Tacoma 4x4

    98 Tacoma 4x4 Well-Known Member

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    The rear cat on yours is either an aftermarket cat or it's just missing the heat shield.
     
  10. Feb 2, 2017 at 1:16 AM
    #10
    Wyoming09

    Wyoming09 Well-Known Member

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    The heat shields rusted off

    Even Aftermarket cats come with heat shields
     
  11. Feb 2, 2017 at 1:23 AM
    #11
    kasemo223

    kasemo223 [OP] Member

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    as far as i know everything was stock(except the grey wire mod) when i purchased this from a friend of a friend and it sounds completely stock ,very quiet indeed compared to my other friends who own aftermarket exhausts, and i want to thank you both for replying back so quickly :p this was a good introduction to this forum and i will be back for sure
     
  12. Feb 2, 2017 at 1:24 AM
    #12
    Wyoming09

    Wyoming09 Well-Known Member

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    Super Springs
    Glad we have your issue figured out
     
  13. May 10, 2019 at 6:28 PM
    #13
    Tacoma/Taco

    Tacoma/Taco Well-Known Member

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    Tacoma13'build in process
    3inKing coilover with clickerreservoirs 600lb King struts clicker reservoirs Total choas UCA Total choas Race series LCA Total choas bed stiffnners Timberland bump stops front/rear Welded gusset All pro aluminum apex bumper Warn 9000 Pia fog lights Pia off road light led Baja light bar Spider projection lights U bolt flip kit All pro 3in expedition leafs ARB front & rear locker ARB twin compresser Large ARB tank 4:56 gear ratio CBI slider bolt on CBI rear bumper steal Marlin crawler Taco Box 4:7 Optima blue top BFG 285/75R17 mud tires Body mount chop 1.25 wheel spacer Budbuilt Full body armor with crossmember support for dual transfer case skid plate Redirected exhaust Spider headlights warn Synthetic winch line Factor 55 fairlead Fiberglass hood, front-rear fender wells Beaded rims Spare tire mount in bed
    It’s a missing heat shield
     

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