1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

P0125 Code after 02 Sensor Replaced!

Discussion in '1st Gen. Tacomas (1995-2004)' started by goomba, Oct 10, 2011.

  1. Oct 10, 2011 at 6:14 AM
    #1
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    I Have a 96 Tacoma 4x4 v6 and I have been trying to find out what is causing this code(p0125). I have replaced valve cover gaskets(not because of code), 02 sensors(it turned out to be a completely clogged cat), d-clogged cat and then replaced fuel filter. I did also notice that the PCV valve is leaking oil into the throttle body, and i will be replacing it soon. Also, my fluid temp, when warm, will reach 190 then drop to 184-187. If you need anymore info I have my own scanner. I have tried to search for this code after people replaced there 02 sensor and found nothing.
    Thanks.
     
  2. Oct 10, 2011 at 8:19 AM
    #2
    DblCabMN

    DblCabMN Well-Known Member

    Joined:
    Mar 22, 2011
    Member:
    #53498
    Messages:
    722
    Gender:
    Male
    Mpls, Minnesota
    Vehicle:
    03 DC TRD/LTD
    Bilstein 5100's all around - Toytec/Eibach 112-620 Coils, Wheelers 5-Pack+Wheelers 2"AAL. 33x10.5x15 KM2s - Siped on Summit Racing 84-5883 rims with 3.750 BS. 4.88s. Demello HD round sliders. Home built full skids. Home built front bumper. Plasti'd badges. Energy Susp. steering rack bushings. Sway bar delete. Deck plate mod. aFe Pro-Dry. Gibson exhaust.
  3. Oct 10, 2011 at 11:12 AM
    #3
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    I got all of my parts from the near by Toyota dealership.
     
  4. Oct 10, 2011 at 12:14 PM
    #4
    DblCabMN

    DblCabMN Well-Known Member

    Joined:
    Mar 22, 2011
    Member:
    #53498
    Messages:
    722
    Gender:
    Male
    Mpls, Minnesota
    Vehicle:
    03 DC TRD/LTD
    Bilstein 5100's all around - Toytec/Eibach 112-620 Coils, Wheelers 5-Pack+Wheelers 2"AAL. 33x10.5x15 KM2s - Siped on Summit Racing 84-5883 rims with 3.750 BS. 4.88s. Demello HD round sliders. Home built full skids. Home built front bumper. Plasti'd badges. Energy Susp. steering rack bushings. Sway bar delete. Deck plate mod. aFe Pro-Dry. Gibson exhaust.
    Right - so they sold you a Denso O2 sensor then? Not a BOSCH or other manufacturer right? Check your receipt and make sure, these trucks are picky when it comes to O2 sensors.

    Also - which O2 did you replace? Front or rear? (closest to the engine or closer to the muffler)

    Double also: If you bought from the Toyo dealer - you most likely paid way to much for the part - again, check your receipt, then check

    http://www.urdusa.com/More-Products.../index.html?osCsid=dd1c7auaadcmaiu2k1u453mul4

    for just about the best price on the correct O2 sensor(s). Return your Toyota one saying it's defective after getting your new one from URD in.
     
  5. Oct 10, 2011 at 3:16 PM
    #5
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    I have denso's yes, and I have replaced both. I have had them for a coupple months. :/
     
  6. Oct 10, 2011 at 3:45 PM
    #6
    DblCabMN

    DblCabMN Well-Known Member

    Joined:
    Mar 22, 2011
    Member:
    #53498
    Messages:
    722
    Gender:
    Male
    Mpls, Minnesota
    Vehicle:
    03 DC TRD/LTD
    Bilstein 5100's all around - Toytec/Eibach 112-620 Coils, Wheelers 5-Pack+Wheelers 2"AAL. 33x10.5x15 KM2s - Siped on Summit Racing 84-5883 rims with 3.750 BS. 4.88s. Demello HD round sliders. Home built full skids. Home built front bumper. Plasti'd badges. Energy Susp. steering rack bushings. Sway bar delete. Deck plate mod. aFe Pro-Dry. Gibson exhaust.
  7. Oct 10, 2011 at 7:30 PM
    #7
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    I took a hammer to the insides. Idk what it is called, but there is nothing inside of the cat at the moment.
     
  8. Oct 10, 2011 at 7:59 PM
    #8
    Tacoma Mike

    Tacoma Mike 48 Year Chrysler/Toyota/ASE/ Master Tech.RETIRED

    Joined:
    Aug 6, 2011
    Member:
    #61230
    Messages:
    28,702
    Gender:
    Male
    First Name:
    Mike
    Southern Maine
    Vehicle:
    2011 Double Cab V6 1995 Bass Tracker
    Large Storage Box, 02610 intermittent switch swap, "Hot Wire" Power Outlets, DRL Shut Off, Disable Fob Beep, Disable Seat Belt Buzzers, Parking Light Mod, Battery Tender, 4 Leaf Spring Pack, Rear Headrest Removal, Factory Tow Package (7 Pin) Rear Diff Mod, Taco Lean Mod, 2WD Low ECU.
    You more than likely have a bad a/f sensor.

    Bad a/f sensor will throw a p0125 code in earlier Toyotas

    Once you fix that the check engine light will come back on for a cat problem.

    Your temp seems to ok a this point.
     
  9. Oct 11, 2011 at 5:47 AM
    #9
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    I am kinda confused i thought the a/f sensor was the front 02 sensor. Or is it the one connected to the air box.
     
  10. Oct 11, 2011 at 1:43 PM
    #10
    Tacoma Mike

    Tacoma Mike 48 Year Chrysler/Toyota/ASE/ Master Tech.RETIRED

    Joined:
    Aug 6, 2011
    Member:
    #61230
    Messages:
    28,702
    Gender:
    Male
    First Name:
    Mike
    Southern Maine
    Vehicle:
    2011 Double Cab V6 1995 Bass Tracker
    Large Storage Box, 02610 intermittent switch swap, "Hot Wire" Power Outlets, DRL Shut Off, Disable Fob Beep, Disable Seat Belt Buzzers, Parking Light Mod, Battery Tender, 4 Leaf Spring Pack, Rear Headrest Removal, Factory Tow Package (7 Pin) Rear Diff Mod, Taco Lean Mod, 2WD Low ECU.
    you are correct.
    A/F (air fuel ratio) is the front sensor and the 02 is the rear.

    They play mumbo jumbo with the sensor names.

    Up by the box you have various sensors named differently depending on the years they were built.

    Open or short in A/F sensor circuit
    A/F sensor
    ECM.

    I know it's a bit confusing with insufficient coolant temp and it does work with the ecu to work for closed loop.

    Take a step back and remember what you did. The only thing you did was change sensors. You had no codes for this before the change

    I'm not there so i can't check it for you but just go back and recheck your work to make sure you have good connections and no broken wires.
    i know this might sound stupid but if you don't find anything and had your old sensors i would throw them back in.

    Whats the time frame between replacing the sensors and the code ???
     
  11. Oct 11, 2011 at 4:17 PM
    #11
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    At first I had 2 codes i think they were p0130 and po133 saying both sensors were bad. Replaced them. Then i dumped the cat, got five codes, p0130, p0125 then others that i forget. Then i replaced the fuel filter got the p0125 code left and it keeps coming back. I just cleaned my MASS AIR FLOW sensor and replaced my PCV valve, and still code comes up. I replaced PCV valve coz it was leaking oil into the throttle body. But i will check my wire connections. and get back with you.
     
  12. Oct 11, 2011 at 5:35 PM
    #12
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    I checked my 02 sensors on the exhaust, and where they plug in on my transmission. The wires are plugged in good and connections are good and clean. The 02 sensors are sealed well on the exhaust. What do you think I should do next?
     
  13. Oct 11, 2011 at 6:24 PM
    #13
    Tacoma Mike

    Tacoma Mike 48 Year Chrysler/Toyota/ASE/ Master Tech.RETIRED

    Joined:
    Aug 6, 2011
    Member:
    #61230
    Messages:
    28,702
    Gender:
    Male
    First Name:
    Mike
    Southern Maine
    Vehicle:
    2011 Double Cab V6 1995 Bass Tracker
    Large Storage Box, 02610 intermittent switch swap, "Hot Wire" Power Outlets, DRL Shut Off, Disable Fob Beep, Disable Seat Belt Buzzers, Parking Light Mod, Battery Tender, 4 Leaf Spring Pack, Rear Headrest Removal, Factory Tow Package (7 Pin) Rear Diff Mod, Taco Lean Mod, 2WD Low ECU.
    If you read my prev post I suggested putting your old sensors back in if you didn't destroy them. Thats the only thing you did and now your getting this
    p0125 code.

    Another thing i would do if you didn't is disconnect the battery for a time so the ecu can get a fresh start.
    the two codes you mentioned are for the same sensor.

    So something is not right here.

    I hope you got the right sensors for the right spot.

    how long did this take to show up ??
     
  14. Oct 11, 2011 at 6:39 PM
    #14
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    I tossed the old sensors. :/ I had the parts guy look up the part via my vin #, and you cant mix up front from rear. the rear 02 sensor cord is not long enough to work in the front.
     
  15. Oct 11, 2011 at 6:41 PM
    #15
    Tacoma Mike

    Tacoma Mike 48 Year Chrysler/Toyota/ASE/ Master Tech.RETIRED

    Joined:
    Aug 6, 2011
    Member:
    #61230
    Messages:
    28,702
    Gender:
    Male
    First Name:
    Mike
    Southern Maine
    Vehicle:
    2011 Double Cab V6 1995 Bass Tracker
    Large Storage Box, 02610 intermittent switch swap, "Hot Wire" Power Outlets, DRL Shut Off, Disable Fob Beep, Disable Seat Belt Buzzers, Parking Light Mod, Battery Tender, 4 Leaf Spring Pack, Rear Headrest Removal, Factory Tow Package (7 Pin) Rear Diff Mod, Taco Lean Mod, 2WD Low ECU.
    Was this code immediate after replacement ??
     
  16. Oct 12, 2011 at 6:09 AM
    #16
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    Yes it was. I may change my thermo and my coolant temperature sensor next. Would that be a good idea?
     
  17. Oct 12, 2011 at 3:39 PM
    #17
    Tacoma Mike

    Tacoma Mike 48 Year Chrysler/Toyota/ASE/ Master Tech.RETIRED

    Joined:
    Aug 6, 2011
    Member:
    #61230
    Messages:
    28,702
    Gender:
    Male
    First Name:
    Mike
    Southern Maine
    Vehicle:
    2011 Double Cab V6 1995 Bass Tracker
    Large Storage Box, 02610 intermittent switch swap, "Hot Wire" Power Outlets, DRL Shut Off, Disable Fob Beep, Disable Seat Belt Buzzers, Parking Light Mod, Battery Tender, 4 Leaf Spring Pack, Rear Headrest Removal, Factory Tow Package (7 Pin) Rear Diff Mod, Taco Lean Mod, 2WD Low ECU.
    I think your going in the wrong direction myself. It's showing 190 on the scan tool you said so that's plenty hot enough.

    Sorry I can't be more help but at this point you need some wiring checks. i still think you have a bad AF sensor or wiring issue. Like i said it's a mis represented code and does not reflect coolant temp for that year.

    It was immediate after sensor replacement. So don't you think that's where you should go?

    Good luck..........................
     
  18. Oct 13, 2011 at 5:57 AM
    #18
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    Thanks for the help.
     
  19. Oct 13, 2011 at 6:40 AM
    #19
    Tacoma Mike

    Tacoma Mike 48 Year Chrysler/Toyota/ASE/ Master Tech.RETIRED

    Joined:
    Aug 6, 2011
    Member:
    #61230
    Messages:
    28,702
    Gender:
    Male
    First Name:
    Mike
    Southern Maine
    Vehicle:
    2011 Double Cab V6 1995 Bass Tracker
    Large Storage Box, 02610 intermittent switch swap, "Hot Wire" Power Outlets, DRL Shut Off, Disable Fob Beep, Disable Seat Belt Buzzers, Parking Light Mod, Battery Tender, 4 Leaf Spring Pack, Rear Headrest Removal, Factory Tow Package (7 Pin) Rear Diff Mod, Taco Lean Mod, 2WD Low ECU.
    Your welcome

    Hope you get it straightened out. :wave:
     
  20. May 31, 2012 at 10:32 AM
    #20
    goomba

    goomba [OP] It is a Fluid Situation

    Joined:
    Sep 3, 2010
    Member:
    #42666
    Messages:
    1,216
    Gender:
    Male
    First Name:
    Josh
    San Antonio Fl
    Vehicle:
    96 White Ex. Cab Tacoma TRD 4X4
    3" lift Up front(Donahoe Racing ext. travel coil overs, Camburg UCA's), 1.5-2" lift in the back(aal and some billy 10" stroke short bodies), Bushwhacker Cut-Out fender flairs, 16"x10" Procomp Street locks, and 305/70 Procomp X-Terrains.
    Found out it was a wrong 02 sensor.
     

Products Discussed in

To Top