O2 Sensor Replacement

[@TimmyTheToolman]

*PLEASE READ THIS COMMENT AND THE VIDEO DESCRIPTION FOR HELPFUL INFORMATION* After doing more research and asking questions on a Toyota forum, it seems the consensus is the downstream O2 sensor is just for monitoring the catalytic converter function and has nothing to do with regulating the Air/Fuel mixture. I'm still not 100% convinced this is the case and I'm fine with the fact I might have wasted money replacing the downstream O2 sensor. I have gone through a couple tanks of fuel since doing this job and it does appear I have improved my gas mileage. But, since it's hard to duplicate the exact driving conditions before the job, I can't say for sure how much it improved. Before the job, the best mpg I saw was 15.4 and that was mostly highway driving with some city driving. After the job, I went through a tank of fuel with similar driving, mostly highway with some city and I got 16.7 mpg. When I did 100% highway, I recorded 19 mpg.

[@riverahector559]

So long term, did it improve mpg? My 99 gets about 14 mpg highway, I love it but hate driving it for that reason.

[@dangda-ww7de]

time to get an ecoboost f150 2.7L , lol @@riverahector559

[@Rhaspun]

I got about the same increase after replacing the sensors on my 1997 4Runner. The increase was just under 1mpg. Now I get consistently over 18mpg. This has been repeated now after several refills. This is with a combination of highway and city driving. Not a huge increase but any increase is good. I haven’t tried 100% highway driving yet. I used to get 21.5 mpg on the highway when it was new. If I can reach 22mpg on the highway it would be great. I have 397k miles on the car.

[@VarroTigurius-u1f]

At 20 years / 170k miles I'm looking at doing this for my 2000 4Runner. Come to find out that after 99 you also need to look and see if your vehicle is Calif or Federal EPA emissions. The Calif emissions vehicles have AFR (air fuel ratio) sensor for the upstream and basic O2 sensor downstream. Federal EPA (non Calif) vehicles use the same O2 sensor for both the upstream and downstream sensors. Additionally manual transmissions and 4wd/2wd all use different sensors.

[@Popcornbeetle]

Thomas Coolidge should ca 4runner’s change the front afr or o2 sensor first when you get the dreaded CEL?

[@jvogler_art4708]

My engine had no codes but when I replaced both o2 sensors, I’m getting way better mpg and now the engine feels like factory smooth. The truck has never felt this smooth. Not ever. It feels amazing. So happy, it’s like a brand new truck.

[@TimmyTheToolman]

That's great you got a good result after swapping out your sensors. Good job!

[@efil4kizum]

what year is your rig? 5VZFE engine with a manual transmission? @jvogler_art4708

[@Redrobinstreet]

My 2001 3.4 V6 Tacoma had a CEL for P0420 recently. I changed the upstream 02 Sensor. Denso of course. After the change I drove about 20-30 miles and light went off. I am the original owner and in my experience the P0420 is always the 02 sensor. Thanks Tim.

[@TimmyTheToolman]

You're very welcome. Glad you fixed your issue.

[@tony_lopez]

Doesn’t the P0420 code mean it’s a defective catalytic converter (front)? So it can also mean the upstream 02 sensor as well?

[@haydenb8853]

​@@tony_lopezyou've gotta use a scan tool to check voltage basically. If your upstream is good and downstream is bad, you either have a bad cat or bad downstream

[@Amraam23]

Hey Timmy I bought your scanning tool/device and worked perfectly with an app car scanner. Almost imidetelly I notice contants 0V reading on my o2 sensor 1 (before cat). Made some basic checks and cosinder it's broken. replaced both sensor (just in case) removed error codes P0171 and P0125 and guess what! No more check engine light. Huge improvement on engine general work. No more missfire, no more high rpm at idle and huge improvemt on MGP. Before replacement I was having 10-13MPG now on highway at 65-70 I am getting 18MPGs. I am so happy with my work. Its a pity we are leaving on differen continents. I would hug You ;)

[@TimmyTheToolman]

Good to hear you were able to fix your issue and our video assisted you. Thanks for taking the time to comment. We appreciate it!

[@Gretzky2857]

I just replaced both sensors and it wasn’t too bad. I have a 2002 4Runner SR5, 4WD with 156,000 miles. My specific part numbers are Denso 234-9002 (upstream) and Denso 234-4261 (downstream). All in, it was about $189 which is a far cry from the approximate $800 quote I got from Toyota, wow! Timmy thank you so much for your videos, everything is explained so well it which makes it very doable. From the time I got my truck on ramps to putting my tools away it was about 1.5 hours. Just took my time and had patience getting off a few of the nuts being that everything was original and I live in beautiful Indiana with salty roads!! Anyway thanks a ton TT , do this job yourself guys and save a ton of $$$ and have the satisfaction of doing it yourself!!

[@TimmyTheToolman]

Hey Tom, glad the job went well for you. $800 is a crazy amount for this job. I bet it felt good doing your own work and knowing all the money you saved yourself. Great job and you're very welcome. Thanks for taking the time to comment and share your success story with us. Happy Wrenching!

[@jamesfarmer2748]

Just finished replacing my upstream o2 with a new denso. No major rust issues but the previous owner rounded both nuts off. Had to use alternate rounds of pb blaster and propane torch to eventually get them off with some vice grip pliers. I was hoping for immediately better mpg but time will tell.

[@TimmyTheToolman]

Well James, you won the war and that's what counts. Hopefully you'll find an improvement in mpg.

[@curtisf1276]

4 years later...my have times changed. $193 just for the upstream sensor. THANK YOU for saving me a lot of headache. I have a 2000 gen3 4runner (original owner) that I purchased in AZ, it has the CA emissions sticker under the hood. A lot of the parts stores do not even acknowledge this detail, and would have ended up getting wrong part.

[@TimmyTheToolman]

You're very welcome Curtis.

[@janaemcdaniel6596]

That's likely because yours is the CA model. I just bought both upstream & downstream from Amazon, DENSO brand,, for $124 tax & shipping included.

[@davidloera15]

@@janaemcdaniel6596Hi. I just bought my upstream from Amazon at $150 alone. Auto parts were charging $200. You got a deal. I changed upstream to clear code p1135, but now I’m getting code p4020. I’m going to change the downstream hoping that will clear the code. Crossing fingers it’s not a bad cat

[@richlien5598]

As always great video and thanks so much for sharing your experience. I replaced the O2 sensor, cleaned MAF and still got the CEL. Finally replaced the oily crusty PVC valve. No more CEL and better gas mileage.

[@TimmyTheToolman]

Good to know you figured out your issue and improved your mpg.

[@actionjackson9290]

Thanks to your video, I just replaced my upstream and downstream O2 sensor on my '99 4Runner and I feel like my truck has become more fuel efficient. Living in Canada, my downstream O2 sensor gasket was rusted after 20 yrs. My next project is replacing rear wheel seal...I'm watching your video multiple times. Keep up the good work!

[@TimmyTheToolman]

Hey Action Jackson, you're name wouldn't be Carl Weathers by chance, eh? Good to hear our videos are helping you out. Good luck with the rear axle seal job. Happy Wrenching!

[@jvogler_art4708]

Have the exact same story. No rust on my truck whatsoever, but the downstream was rusted and corroded and crumbling. The new o2 sensors made a gigantic difference.

[@lifeguard92646]

Thanks Tim, I changed both O2 sensors today in my '03 Tacoma. Easy-peasy after watching your video. No more check-engine light. I always search your channel before any repairs. Cheers mate!

[@TimmyTheToolman]

Glad our video helped you out Damien.

[@aharris8222]

I'm swapping out the O2 sensors as a last resort to fight my high Idle on my '99 4 rnr. I was chasing a mis-fire and tried Seafoam and the idle bumped up and has continued to climb to 1400-1800 rpm. I have new TPS, IAC, spark plugs and wires, fuel injectors, gaskets, MAF sensor, new hoses from smoke test for vacuum leaks. temp sensor check out OK. No slop in throttle body input shaft. THX for all the great videos, lungfish

[@TimmyTheToolman]

Hope you figure it out.

[@Claude-om9og]

Did you find the problem? I just watched a video with the same high rpm problem and it ended up being a bad thermostat not allowing the coolant temp to get hot enough to tell the IAC to close and lower the rpm.

[@Swimnbud]

Thanks!

[@TimmyTheToolman]

You're very welcome!

[@WMAT77LL]

Just done this on my 04 v6 Manual trans, the sensor was easy to unbolt but getting the wire harness unplug took me a while,the wire went up above the trans I couldn't see so had to do so feeling around I guess Auto and Manual trans are lil different thanks for sharing the info about the downstream and the vid

[@TimmyTheToolman]

Those connectors can be a pain in the butt to disconnect. Thanks for the comment and you're very welcome.

[@BrockOBauma]

Same deal on my manual T100. The connector is mounted on top of the tranny.

[@scubbarookie]

Hey Tim thank you for this detailed instruction.... Your videos are probably the best in their applications and detail! Take care brother! 👍🏞🏜

[@TimmyTheToolman]

You're very welcome and we appreciate your compliment. You take care as well.

[@johnaustin2276]

Gonna do the down stream on my 02 tacoma and my mechanic suggested to use a 6 piont on the bolts to lessen the chance of stripping. Thanks for the video.

[@TimmyTheToolman]

Hey John, yes, a 6 point socket or 6 point box end wrench will definitely lessen the chances of stripping one of the nuts. Your mechanic shared good advice. Make sure to pretreat the nuts with some penetrating oil especially if you have some corrosion. Good luck with the job and Happy Wrenching!

[@DoubleHaulCharters]

I just did the AFR on my Tacoma. The nuts seem to be made of a softer than normal metal. Make sure whatever tool you decide to use is fully seated on the nut before applying torque.

[@johnaustin2276]

DoubleHaulCharters thanks for the info.

[@davidpenney4171]

Both O2 sensors on my '96 T100 V6 are original, 128k miles. The nuts are so corroded I've had to order the upper exhaust manifold/catalytic converter pipe as well as the cat. Will have a muffler shop finish the job.

[@TimmyTheToolman]

Yeah, a muffler shop can install a new O2 sensor bung for you if rust has eaten up too much of the studs.

[@efil4kizum]

both 02 sensors on my '97 Taco 5VZFE MT are original at 344k miles... had a clutch job done and rebuilt R150F that took 12 weeks to complete with exhaust opened for removal/assembly of the clutch... got the truck back and NOW get 50 miles LESS per tank... is it these 02 sensors? truck has No CEL triggered @davidpenney4171

[@TimmyTheToolman]

@@efil4kizum Calculating by tank is not the most accurate way to determine mpg. You fill your tank, reset your trip odometer, and then drive. On your next fill up, you divide the miles you drove by the gallons it took to refill your tank and that's how you properly determine mpg. If you're O2 sensors are original, it wouldn't be a bad idea to replace them. There's no guarantees it will increase your mpg, but there's a chance it will.

[@efil4kizum]

@@TimmyTheToolman thank you for the instruction on the best way to measure MPGs... here is how i do it for decades on this truck with an ongoing ledger... i wheel it until the low fuel red light comes on... wheel another 20 miles or so to the next spot for some fresh tacoJuice... fill up until the pump handle clicks. keep pumping the juice in slowly to round it up... i can usually fit in more than an extra gallon before fuel starts spitting back out at me LMAO... Many will frown upon that method but i have YET to find any issues doing this over 200k miles of doing it that way... then normal driving (mostly freeway at 65 to 80 with an occasional 95mph when it needs the exercise) yields very close to 360 miles before the red low fuel light has triggered for 20 miles... now it barely gets to 300 miles on that tank over the past 2k miles... this is called the hardcore TacoLife living midWest style... i wheeled it through the heart of Minneapolis on i94 this week and did NOT SPOT 1 Gen1 Tacoma nor Gen3 T4R... its very sad to be all alone out here in the rusty crusty saltbelt 8^(

[@davidpenney4171]

Job completed, and check engine light is gone. I had to buy an aftermarket catalytic converter and down pipe from the manifold, both discontinued by Toyota. So this was an expensive repair.

[@8953147]

If you have a graphing scan tool, monitor both upstream and downstream O2 sensors. If the downstream sensor mirrors the upstream the CAT is dying. The downstream sensor should be steady in its output, as it reports to the PCM how the CAT is responding. Great video as always my brother Tim!!

[@TimmyTheToolman]

Thanks for the info Brother Jake. I have that Torque Pro app but I don't think that would offer the information you're talking about. Somebody else mentioned using Techstream but it requires a windows based operating system and all I have is a Mac now.

[@8953147]

Timmy The Toolman Any hand held graphing scan tool, $200-300 range would work.

[@TimmyTheToolman]

Gotcha. I'll have to look into finding a good one.

[@jb_1167]

Thanks for putting this video together. Had to replace the forward o2 sensor on my '98, and this showed me exactly where it was. The flex-head ratchet suggestion made the job a lot easier in the tight space. I still had to fix that the PO put 2 SAE nuts on one of the studs (one too large to touch threads, and the other clamping it down, but screwing up the top threads on the stud), but that's what tap & die kits are for, and even that wasn't hard. The guidance was much appreciated.

[@TimmyTheToolman]

Previous owner put SAE bolts in?!? Some things people do is unreal man. Thanks for taking the time to comment and adding your experience to hopefully help others. We really appreciate it Jonathan!!!

[@uzm2589]

Followed this step by step and the CEL on my 99 SR5 is gone!!! Love this channel

[@TimmyTheToolman]

Glad this worked out for you Tito. Thanks for taking the time to comment. Happy Wrenching!

[@israelrodriguez6986]

Just did this job right now, thanks for the videos yall make Timmy and Shawn, i learn alot from them. The results for me were a success.

[@TimmyTheToolman]

Good to hear Israel. Glad you had success with this job using our video.

[@kennysmoke]

I have a 98 4 Runner and live in the rust belt of WNY, but the vehicle originally came from Canada. I'm doing a cat back exhaust replacement tomorrow and was curious about the O2 sensor removal. Very informative video.

[@TimmyTheToolman]

Good luck with the job. Glad you found the video helpful.

[@alirazmjou2149]

Thank you so much for this video متشکرم از شما آقای محترم

[@TimmyTheToolman]

👍🏻

[@weekendclimber]

Timmay, to speed up the EFI recalibration you should pull the EFI fuse for an hour or so. This will erase all data it's using and start you fresh. Good video, and good information all around!

[@TimmyTheToolman]

Thanks for the tip. Glad you like the video.

[@moose354]

Timmy - why didn't you go for the trifecta and clean the throttle-body too. Great walkthru on the O2 replacement. I had to replace the downstream on my 3.4 liter Tundra because the heater element died.

[@TimmyTheToolman]

My throttle body was already clean from a recent valve cover gasket job. But yeah, not a bad idea to clean the throttle body and also clean the IAC valve.

[@inhocsigno9151]

Anti-seize on the threads of the mounting studs before putting the nuts on helps the next time the nuts are removed.

[@TimmyTheToolman]

Yeah, I agree with that. Thanks for the comment.

[@VeryPersian]

I had to have a new flange made at the exhaust shop. Those studs rust quick. The one they made for me used bolts instead of studs which should last longer with stainless steel bolts.

[@jamesflores9456]

where do you live?... mine came off without a problem... didnt even use penetrating fluid

[@ponyboyack00]

I've got to do this to my 99 SR5 Highlander edition. It's 48 state Federal living in the great state of CA, you don't even want to hear my unnecessary California Smog issue story. But, it's been getting poor MPG, like maybe 15. I've been trying to figure it out, stumbled onto the O2 sensor idea in a forum, and thankfully the great TimmyTheToolman has addressed it in a video. I'm hoping to get at least 2 MPG more after this. It's running slightly oversized tires, but has been since I bought it 10 years ago.

[@TimmyTheToolman]

Hopefully it improves your gas mileage. Let me know how it turn out. I think mine improved a little but it's hard to say how much.

[@ponyboyack00]

Will do. I'm going to take a few tanks and get a good avg. mapped out. Will try to get an idea of specific Hwy avg. too. But I've been trying to figure out my MPG drop off and on for a while now. Was considering the deckplate mod, and even bought an Airaid wondering if the cracked rubber on OEM intake tube was a problem. It's been tuned up, cleaned up the throttle body, MAF etc. I'm hopeful with the O2 sensor/s, just deciding weather to do both. Might as well I guess. 177k, from Utah, so salted roads, and Sacramento summers. These 3rd gens are tanks, but I am eyeing a LX470, or newer 4Runner. With my mileage so poor, a LC or LX isn't much different..

[@ponyboyack00]

@@TimmyTheToolman It seems to just be the driving conditions for my MPG. Recently we took it for a longer, mostly freeway trip and got over 20 mpg with 90% HWY driving. So I have determined it is the driving conditions. Seems to get 14.5 - 16.5, with mostly city z 60% city, but over 20 mog on the HWY. So I am leaving the sensor alone for now. Mine is aeruouslt rusted, so not worth the trouble unless malfunctioning. Hoping for a door lock actuator replacement video, with the cheap motors instead of the full part. My Drivers lock is failing, particularly if the door is getting direct sun. There are write ups on the forums. But I imagine a lot of these are starting go out at this point. Could be worth a video for you, maybe not? Anyway thanks for your vids, they are above and beyond the best... I'm hoping you get into 100 series Landcruisers next, I have been eyeing LX470'S lately..

[@TimmyTheToolman]

Yeah, probably a good idea to leave that sensor alone. We will definitely be doing a driver door lock actuator sometime soon. I need it on my 98. My door lock doesn't always open all the way. It closes fine though. Glad you think so highly of our videos. I would actually like to own an old FJ40 or a 1st Gen 4runner.

[@jordancrockerlv7489]

I’m having the same problem with my 95 4Runner, I think I might follow your lead and replace my sensors as well I’m getting around 15 mpg on a good day lol

[@CrazyforCruiser]

I have an old LS400 with 300k miles and it was burning more fuel than my Land Cruiser. LS400 dual exaust and it has 4 O2 sensors. Before replacing sensors it was doing 6 MPG after O2 sensors now the mileage has greatly improved.

[@TimmyTheToolman]

That's good to hear it worked to improve you mpg.

[@calebrichter2565]

found the info i needed in your video description! was worried I didn't get the right sensors but mine is a '96 and I have two of the same 02 sensors so I should be all set. Thanks for all your help!

[@TimmyTheToolman]

Glad our video could help you out Caleb. Happy Wrenching!

[@raymondroyce4471]

You are a true professional, explaining and working. My sincere congratulations.

[@TimmyTheToolman]

Thanks Ramon. We appreciate the nice compliment. Happy Wrenching!

[@williamavery1758]

Oh wow very good video I have a 1998 Toyota Camry V6 3.0 and im getting ready to do the other upstream 02 sencer cause the same thing my gas mileage is not that good I think it can get alittle better. Plus on my scan tool all the monitors are good but my 02 sensors one is saying incomplete. Bank 1 sencer 2 has to be changed im pretty sure, but my Mechanic is gonna put the scan tool with live data on tomorrow to make sure I change the right sensor. And hopefully my has mileage will go back up, and im gonna have him spray the mass air flow sencer as well

[@TimmyTheToolman]

Good luck with the job. Hope the O2 sensor swap fixes your issue and improves your gas mileage.

[@williamavery1758]

@Timmy The Toolman Thank you brother

[@TimmyTheToolman]

@@williamavery1758 You're welcome.

[@racerxnk]

Love seeing your rust free vehicles. A little jealous too:)

[@TimmyTheToolman]

Yes, we are spoiled in the California Bay Area.

[@Rhaspun]

Go to South Main Auto. That guy works in New York state. I find it unbelievable how much rust can build up every where.

[@gewglesux]

@@Rhaspun same here... it's that liquid Acid they put down here..Everybody leases here! Those of us who like to keep our autos are screwed.

[@tynado1173]

Same

[@gewglesux]

@@tynado1173 I'm re doing my exhaust so i'm going to replace my sensors anyhow. The current one is melted on with rust.

[@kellsENY]

Thanks for your video!! We need more people like you videoing and explaining your job. Thanks !!!

[@TimmyTheToolman]

You're very welcome and thanks for the kind words. Happy Wrenching!

[@rozhill4500]

All videos should be this good.Thank you

[@TimmyTheToolman]

Thanks! We appreciate the compliment.

[@israelrodriguez6986]

I'm just throwing this out there, someone may actually have an ansr to or at the least a great suggestion for repair. My dads 2002 toyota 4runner had the TRAC OFF and the VSC TRAC light on without the check engine light. I simply disconnected the negative cable for a few minutes and put it back on, it cleared the lights. But in the event that they possibly return, would anyone have experienced this or just know what could be a route to take in clearing them permanently??? Thank guys! And great video, Tim. Keep up the great work!!!

[@TimmyTheToolman]

Hey Israel, I don't have personal experience diagnosing this issue but I do know it's come up on T4R.org. I think a Google search will bring you to several forum threads on the subject.

[@DarrenMyrum]

hey tim thanks for video up here in WA we dont have emissions anymore we did for awhile ,I am wanting to get rid of the cat converter, cant find anythhing on youtube, can you suggest some ideas or point me in the direction , 2000SR5 4RUNNER THINKING ABOUT PUTTING A V8 IN AROUN 10000 .THANKS TIM ANS SHAWN FOR ALL YOUR GOOD KNO EDGE YOU REALY HELP US OUT ALL THE TOYOT...A WORLD LOVES YOU . DARREN

[@TimmyTheToolman]

@@DarrenMyrum Eliminating the catalytic converters is something we don't have experience with since we live in California with strict smog laws. A muffler shop would be able to help you with the job, but dealing with the O2 sensors and the ECU to not have a constant check engine light is something I'm not sure there's a work around, but maybe there is. We have a video for a V8 Swap. kzbin.info/www/bejne/fJTIaHydgrmXgcksi=dRvCPHpt0rN4gFKT

[@TyMan970]

toyota tim you are the man, as always.

[@TimmyTheToolman]

Thanks Ty.

[@robertovalls]

Very thorough, I learned and also subscribed, great video!

[@danielmiles6858]

It always seems you do your videos at the same time I need them. I just had a code come up for my downstream 02 sensor. Last time it was timing belt and water pump. Great Video

[@TimmyTheToolman]

D Miles good luck and happy wrenching! I hope our next video comes as timely as these as well!

[@danielmiles6858]

Timmy The Toolman , I live about 5minutes from the Atlantic Ocean. The bolts are soooo rusted theres no threads on either one. Any suggestions

[@TimmyTheToolman]

Sounds like you need to go to a good muffler shop and see what they can do for you.

[@dand4564]

Another excellent video. Such a clean underbelly compared to here in wisconsin. Thanks!

[@TimmyTheToolman]

Thanks Dan, We're glad you like the video. Yeah, we don't deal with rust in the Bay Area of California. You're welcome and thanks for the comment.

[@jeremyoshea7941]

I know you’re really good at answering questions when you’re able to when you have the time really appreciate the videos to I’m over here in New Hampshire Jerry’s got a Camry we just ran into the California situation with the Cadillac converter the exhaust is rotted the converter still good anyways I have a 02 Tacoma fortunate that the salt hasn’t gotten to it I keep it under coded got it in good shape anyways the door tag says California but underneath the hood on the left side it says Canada I’m not sure how to find out about the O2 sensors And if we have to go with a California O2 sensor or if there is even The same situation with emissions I guess on what part of the tag would tell you the mechanic figure it out the California thing with Kari’s car thanks again for your time

[@TimmyTheToolman]

So the emissions sticker under the hood says it was built to Canada spec?

[@RedRoyce]

thank you for the great video!! I have a 2004 Tundra and have to bank 1 sen 1 out so I'm doing this very thing. So cool you show just how i'm going to have to do it!! Thanks

[@TimmyTheToolman]

You're welcome and glad you like the video. Good luck with the replacement.

[@p0kemon4]

Did it clear the code? I have the same problem with my 03 Tacoma and after changing the sensor it came back on after a few miles. Not sure if I should change the down stream co2 sensor as well?? Any help I’ll greatly appreciate it

[@p0kemon4]

I want to also add that I cleared the check engine light with an obd scanner, idk if it might be better to disconnect the batter instead to reset the whole system?

[@genxiong2695]

Quick question: If you are no longer living in California can you get the non-California EPA part instead?

[@TimmyTheToolman]

I'm not sure. Your vehicle was built to the California emissions spec, so I would assume you would have to use the California spec to avoid a check engine code.

[@genxiong2695]

@@TimmyTheToolman I agree just need a second opinion. I have a 2000 model and the upstream part (Denso 234-9002) is expensive compared to the downstream. Oh well. As always, thank you for the quick reply!

[@richlien5598]

I also have the 2000 model federal emission. 234-9002 connector doesn’t match up. So used the Denso 234-4162 which I crossed reference through Timmy Denso link. Replaced PVC valve and clean MAF and inspect hoses for leaks and cracks. No more CEL and back to spec.

[@ndeeeed]

I think one of my friends got changed 212$ to get the part and labor on his 00 Tacoma to change one o2 sensor . I can’t believe it was this easy

[@TimmyTheToolman]

Hey Daniel, a lot of auto mechanics is pretty straightforward like this job is and it is surprising how much a shop will charge you for something that takes them 15 minutes to replace. This is one of the reasons why we are trying to empower people to do their own work. The other reasons are it's a good learning experience and a skill you can use over and over again, and then there's the great satisfaction you get when you successfully perform a job. Happy Wrenching!

[@BillKirkpatrick]

Excellent explanation of maintenance service, well done!!

[@TimmyTheToolman]

Thanks Bill!

[@wildmustangart1577]

Tim, I know this isn't the subject of this video, but it's nearby. I suspect maybe my Catalytic Converter is bad, I'm suffering a loss of acceleration/power. I don't suspect an engine problem. The 99 4Runner with 3.4L has 380,000 miles on it with the original Cat. Would that mileage alone be enough for the Cat to fail, or would there HAVE to be some underlying problem? Voltage fluctuates below .7v. I know that is a symptom. I'll do a temp test next. Is age alone enough for failure? Thanks!!

[@TimmyTheToolman]

A good muffler shop can tell you if you have a bad cat. They drill a hole and put a probe in to figure out if the cat or cats are bad.

[@nickschuldt9229]

I seen you do work on the 4.7. Was wondering if you have or know how to get the complete wire diagram for the O2 sensors on the 4.7 06 4Runner.?

[@TimmyTheToolman]

You'd have to buy a subscription to Toyota Tech Info. I buy 2-day subscriptions and download what I need. techinfo.toyota.com/techInfoPortal/appmanager/t3/ti?_nfpb=true&_pageLabel=ti_home_page&goto=https%3A%2F%2Ftechinfo.toyota.com%3A443%2Fagent%2Fcustom-login-response%3Fstate%3DshJX0Ta1BXIK0Y3GK5F26E-qIeA&original_request_url=https%3A%2F%2Ftechinfo.toyota.com%3A443%2F

[@jj2956]

Hey Timmy, My check engine light came on giving me a code that my rear 02 sensor was the culprit. Quick look underneath and saw that studs were extremely rusted. Brushed them off with wire brush and sprayed them with PB blaster. First nut came off no problem, second nut came off easily to halfway, and then nut started to really make a screeching sound when I turned nut. I would go back and forth with nut spraying with PB blaster and as I got to the last quarter inch the stud started spinning no matter the direction I turned, and then the stud broke off flush. I put new 02 sensor on with one nut and clamped the other side down with a hose clamp as a temporary fix. I turned over 4Runner to see if I could feel any leaks and discovered about three inches in front of 02 sensor on top of the muffler piping there was a nice size leak. Then everything started to make sense. My muffler had to be replaced about a year ago and the muffler shop ended up having to weld the forward muffler pipe to the catalytic converter pipe together because they said the flange rusted out. Well the leak I’m experiencing is exactly at the weld on top of the pipe which is located three inches in front of 02 sensor. I remember the mechanic calling me saying I’d probably have to replace my 02 sensor. I thought at the time how the hell did that go bad. While at that time I had no idea what an 02 sensor was so I asked how much and once he gave me the price I said to hold off if the one is still good. He said he could try putting back on but most likely will have to be replaced soon. Well a few weeks go by and sure enough my check engine light comes on. Take my vehicle to a shop and they confirm my 02 sensor was culprit. They reset check engine light code and said it would come back on most likely and sure enough it did. I then started watching your videos performing maintenance myself saving a ton of money, learning about my vehicle, and slowly acquiring lots of tools. I eventually got my own obd2 reader to monitor my coolant and transmission temp after I installed a cooler as well as used it to check/clear codes specifically the 02 sensor that kept tripping. The only reason I put off replacing 02 sensor for so long is because of all the rust. Anyhow after breaking my stud off I suspect there was no issue with my 02 sensor in the first place and it was the leak in my pipe a few inches ahead of the sensor. Now almost year and half later I am going to call the shop explain the above to them and hope they’ll repair leak in pipe and weld on a stud for a reasonable price considering the circumstances. I am confident that their poor weld job was tripping the 02 sensor code in the first place and they just reset the code before giving my 4Runner back to me. If shop is not willing to offer a reasonable price I might just order everything ahead of tail pipe and replace it myself. My concern will be removing pipe ahead of the cat because of all the rust! Do you see any other options?

[@TimmyTheToolman]

Replacing the exhaust manifold on that side might be your only option if it can't be repaired by the muffler shop. I haven't pulled off the exhaust manifolds off an engine inside an engine compartment yet. The only ones I've removed have been from an engine that was already pulled out from a rig. It might be a little tight getting to all the fasteners but I think you shouldn't have too much problem. I guess the rusty nuts would probably be the biggest concern.

[@MC-nd3zl]

Would be great if Denso's "find your part" section of the website worked.

[@TimmyTheToolman]

Must be down for some reason. I just checked myself and the site doesn't load. Maybe they'll have it up and running soon.

[@MC-nd3zl]

@@TimmyTheToolman I have a 2002 Toyota 4runner SR5 4wd Automatic w/ 3.4 V6. I found a part number from www.yotadirectparts.com/ using my VIN. I searched some different websites and it looks like Rockauto has the best prices for a Denso. I was just hoping to find Denso's exact part number for this vehicle. The alternate PN (8946735011) for the Denso product on rockauto ( DENSO 2349002) did match the Toyota PN from yotadirect (89467-35011) so I assume I found the right one. Just weird they list an upstream and a downstream when my vehicle only has an upstream.

[@TimmyTheToolman]

@@MC-nd3zl You should have a downstream O2 sensor. Something isn't adding up.

[@MC-nd3zl]

@@TimmyTheToolman Whoa......guess I missed the other one the first two times I went under and looked. It does have two!

[@TimmyTheToolman]

@@MC-nd3zl That's good. I thought somebody did some janky work on your rig and eliminated the rear O2 sensor.

[@robertshirlingjr.6988]

Timmy i went to denso website & put in my model,year & motor size. Im having a p1135 code. But it doesn't ask if its a California emissions or not. So just order the upstream one. Thanks

[@TimmyTheToolman]

You're welcome. Hope it fixes your issue.

[@oscarruiz5076]

Do you have a video on the p0446?

[@TimmyTheToolman]

Sorry Oscar, we don't.

[@HT7980]

The sensors in your links say that they don’t fit a 02 4runner. Not sure what year yours is but are all 3rd gens using the same sensors?

[@TimmyTheToolman]

They don't all use the same sensors. Use the Denso website link in the video description and look yours up.

[@HT7980]

@@TimmyTheToolman have you had any issues running denso sensors? Joe joe is saying it will set off my engine light.

[@TimmyTheToolman]

@@HT7980 No, I haven't. Denso is the company who made the OEM sensors.

[@HT7980]

@@TimmyTheToolman that’s what I thought. thanks for the info!

[@TimmyTheToolman]

@@HT7980 No problem.

[@malendamiller9891]

Sorry to be elementary, but do you need to disconnect the battery before you start? Also, is there a way to feel the 14 fp without the torch test tool?

[@TimmyTheToolman]

When disconnecting electrical connectors, it's never a bad idea to disconnect the battery. I'm sorry, but I don't understand the second part of your question.

[@curt8641]

@@TimmyTheToolman I think he's talking about a Torque Wrench. The general feel of 14 FP is a little less than your German measurement that you use, GuetenTeight..

[@TimmyTheToolman]

@curt8641 Oh yeah, I think you're right, but the Gudentite spec is universal. Whatever you're tightening, you get it, Gudentite, based on the size of the bolt or nut you're tightening. I learned at a pretty young age how to tighten things without stripping or breaking them. You have to understand mechanical advantage, that a longer lever will allow you to deliver more force than a shorter lever. Lots of people live and die by torque specs. They don't know what to do if they can't get their torque wrench onto a fastener.

[@curt8641]

@@TimmyTheToolman Thank you for your content Timmy, you're my goto guy, especially for my 4runner issues. I still have some. I"d like to hit you up for some more insight if i could.

[@TimmyTheToolman]

@@curt8641 You're welcome. What issues does your rig have?

[@luisolitoquit4481]

I loved watching your video. I got a 97 4runner limited with 178,000 miles in it. I went for my biennial smog certification at a star certified station and it failed because the NOx was too high. The mechanic told me that it might be the oxygen sensor. My question is do I need to change both sensor or I can do with the upstream sensor only. One more thing Timmy, I tried another Star certified smog station because I wasn't sure about the first one maybe he just want to rip me off with unnecessary repair and sure enough my truck pass the inspection.Thanks for any reply.

[@TimmyTheToolman]

If you decide to replace one sensor, I'd suggest going ahead and doing both. That was smart of you to try out a different smog station.

[@luisolitoquit4481]

@@TimmyTheToolman Thanks for the good suggestion. You're the man.

[@TimmyTheToolman]

@@luisolitoquit4481 You're welcome Luis.

[@michaelrostrata7456]

Great video. Very informative. So I will be replacing the o2 sensors on my 97 4runner. Got a system too lean code and My question is how can you tell the difference between the upstream and downstream sensor? I don't want to mix them up when I replace them. Thanks!

[@TimmyTheToolman]

Well, just replace them one at a time and you can't mix them up. They have different part numbers so keep them in the box until you're ready to install them.

[@craigjones9723]

Having trouble getting the bolts removed on a 98 4runner. Any advice? Thanks for a reply.

[@TimmyTheToolman]

Heat from a butane torch and penetrating oil. Keep repeating until you get them loose.

[@valdiviajr1]

Hopefully I'll pass the smog check after changing the two 02 sensors

[@TimmyTheToolman]

Yeah, fingers crossed it works out for you.

[@chazzieB2]

Nice camera bud, made the procedure look much easier

[@TimmyTheToolman]

Good to hear Chazz.

[@zman92630]

Thank you for the plethora of information! Great video! My mpg is garbage for my '03 SR5 (about 13/city), but of course I have lots of overlanding weight added (skid plates, rock sliders, roof rack, bigger tires, etc.) Evem though I have no codes thrown, I'm wondering how much ROI in mpg I would get for spending $350 on new O2 sensors ('03 takes 2 upstream, 2 downstream.) Is it worth it?

[@TimmyTheToolman]

Hard to say if it's worth it Chris. These rigs get crappy mileage when they are weighted down. If anything, maybe just replace the upstream sensor because that's the air/fuel sensor.

[@curt8641]

I"m with Tim on this, Mine gets less than acceptible gas mileage, So i look at it this way, Spending the money may not be worth it, but better mileage means better efficiency, which means less stress on the moving parts, less heat, less carbon build up, longer running engine. Money spent VS MPG, no. But worth it? Yes

[@santoslaguna58]

When I removed the gaskets my tacoma, they too were on backwards. I’m not sure if they were changed at some point or if that’s how they came from the factory

[@TimmyTheToolman]

I wonder if the gasket orientation even makes a difference. It might not.

[@joet3123]

Thank you for the video. I have a problem with rust on mine. The nuts are completely rusted and stripped. Any tips to get them off?

[@TimmyTheToolman]

Heat, penetrating oil and see if you can clamp onto them with some vice grips to spin them off. They also make nut and bolt extractors like these that would be the right tool for the job. Bolt Biter Extraction Socket Set amzn.to/32YpFOh

[@mrbeezzyy631]

Their are these extraction sockets they sell at Home Depot give those a try

[@anthonym844]

Good Video ! Thanks You always inspire me to do the job wright!!!

[@TimmyTheToolman]

Thanks Anthony.

[@robertplant9694]

Make sure you have dual electrode plugs. I always find these runners with incorrect spark plugs

[@TimmyTheToolman]

Yes, you are correct Rob. Dual electrode plugs are the correct ones for our rigs.

[@j.d.williams8145]

I bought mine used and when I changed the plugs recently it had single electrode plugs, I reinstalled the doubles as stated. Been doing lots of cleaning to the engine trying to get my mpg up. I am changing the o2 sensor tomorrow. Hope it works.

[@jimkiltz9955]

Timmy The Toolman my 4Runner misfires and runs poorly it has single electrode plug do you think that would be related

[@mcfmwjd]

Do you have a trick to separate the plastic connector? I cannot get the damn thing apart. I'm pushing hard as I can on the tab but not getting it pulled apart and I don't want to maybe pull wires apart.

[@TimmyTheToolman]

Try cleaning behind the release button with some electrical contact cleaner. They sell it at auto parts stores. Then, try pushing in on the connector while pushing the release tab and then pull back and hope it releases. Good luck!

[@mcfmwjd]

@@TimmyTheToolman

[@mcfmwjd]

Thank you for the info. It worked. Do you happen to know if the rubber part those clips attach too are a replaceable part. If so , can they be just pulled out? My are now not attached . That part held them in perfect location.

[@TimmyTheToolman]

@@mcfmwjd I don't know if they are replaceable or not. You can always use zip ties to hold them in place.

[@integridad7]

The downstream has a longer cable

[@TimmyTheToolman]

And it has a different part number too.

[@aqualung1466]

Terrific video - thank you!

[@TimmyTheToolman]

Thanks and you're very welcome.

[@AKcabins]

Great video as always!!!

[@TimmyTheToolman]

Thanks!

[@ciscokid0307]

Hi Timmy,is there a drive cycle instruction procedure on your manual to reset the catalyst monitor? seems like alot of people are having trouble activating their catalyst monitor sensor after disconecting the batery and there is a debate on how to activate your I/m monitor sensors for a smog check. if you can answer this question and make a video I think it will help a lot of toyota owners and thanks for all the awesome videos you have made.

[@TimmyTheToolman]

Francisco Valle if I remember correctly from a recent smog on one of our many 4runners, the procedure to reset the emission systems basically requires you to drive at or above 55 mph for 20-30 minutes. Sean has recently replaced an 02 sensor and took it to the smog shop and they said the system want ready yet and to drive it for 30minutes however we learned later that it’s 20-30 minutes at approximate highway speeds.

[@babaoriley5751]

Awesome video. Very helpful thx

[@TimmyTheToolman]

Glad you found it helpful. You're very welcome.

[@theshocker4626]

Tim. The Denso website doesn't show a diff O2 sensor for Kali versions for 01 or 02 trucks

[@TimmyTheToolman]

That's because by that time, trucks across the country were all built to the California spec from what I've heard.

[@gunsfishand4x4]

Yes I ordered this one for my 02 and there is no oval plate attached. Just a threaded sensor...

[@gewglesux]

Hey dude.. just a question with a multi meter Do you have any idea what the resistance of the bad sensor vs a good one?

[@el__2handed]

Timmy, I picked up a 97 with 175k miles and it does not have not the most detailed service records. I had the sparks plugs changed recently by my mechanic. I want to tackle the O2 sensors and MAF, but I also saw the Seafoam treatment you did on your 2000. Would you recommend doing the Seafoam first before changing the O2 sensors and cleaning the MAF?

[@TimmyTheToolman]

If would do the seafoam treatment first. You're introducing the seafoam directly into the throttle body so you could clean the MAF before or after because the seafoam isn't going to contact it.

[@el__2handed]

@@TimmyTheToolman Thank you very much.

[@selimlilic633]

Nice video I need to replace a o2 sensor on 97 4runner limited 4x4 is it the same part number as yours

[@TimmyTheToolman]

Glad you like the video. Good luck with the job.

[@majamurawska248]

I have a 4th runner from 2000. there is another cube in the sensor behind the catalyst and before. I think something is wrong. do you know this problem. Thanks

[@TimmyTheToolman]

I'm not exactly sure what you're saying. I don't know what you mean by "cube in the sensor". You will have two sensors, one upstream of the catalytic converters and one downstream of the catalytic converters.

[@mrbig7343]

I have a 2000 Toyota Camry 2.2 l 5sfe motor O2 sensor looks like the one you have in your hand but I could not find one in a parts store in Australia looked online and found something similar that fitted 100 series landcruiser in America I think it's called an E300 not 100% on that one but it said it would fit the land cruiser as well as a Camry is this true

[@TimmyTheToolman]

I have no clue. I suggest you look up the part on the Denso Find my Part website we link in the video description and find the correct sensor. You'll get results for the upstream and downstream sensors so be sure to pick the right one and then use that part number to search for it online. Amazon will most likely have it.

[@dominicbassis4462]

Great video will try it on my truck.

[@TimmyTheToolman]

Glad you like the video. Good luck with the job.

[@gunsfishand4x4]

Question: I ordered the correct part for my 02 4R and it does not come with oval plate attached to it?! Toyota says it’s the right part... it appears to just thread in. It’s Denso oem. Have you heard about this? Did they change the 01-02 O2 sensor?

[@TimmyTheToolman]

That's weird. As far as I know, none of them thread into the exhaust, they bolt onto it via the studs sticking out that the oval flange of the sensor slides over and the nuts secure it. Sounds like you got the wrong part. Did you look up the part number via the Denso link we provide in the video description? A quick look under your rig will tell you if our original sensors are just like the ones we show in the video. But again in our experience even the 01-02’s have the oval plate gasket to ensure there isn’t an exhaust leak for both the O2 sensor & the air to fuel ratio sensor.

[@daycinvac]

Tim, thanks for what you do. Your my go-to-guy on You tube for my 2000 Tundra. I have over 420,000 miles on it. I drive the hwy everyday. My 2000 Tundra V6, we have a code of P0125, (Sufficient Coolant Temp for Closed-Loop Fuel Control) The dealership replaced the Thermostat and Coolant. However, after 1.3 miles the check engine came back on. They check again, the same code came up. I'm thinking maybe, the top engine ECT Sensor or the bottom Oxygen Sensors ? Your thoughts? Also, Tim you were going to list the web sight that you use to find parts, or part number less cost than what the dealers uses. Dave

[@TimmyTheToolman]

I haven't troubleshooted the P0125 code before so I wouldn't be much help to you on that issue. Doing a search for the possible causes and diagnosing the easy things first to rule out is what I would do. In the video description, we provide a link to site to look up the part number for the O2 and Air/Fuel sensors. Once you have the right parts numbers, just do a Google search and you'll probably find the sensors you're looking for on Amazon for a fair price. When I'm buying Toyota OEM parts, I usually use Camelback Toyota in Arizona. Their prices are competitive and they ship quick. Amanda is in charge of the online sales for Camelback and she's really helpful.

[@daycinvac]

Tim, please let me know when you feel more confident on that P0125 Code. This light came on two weeks ago. It was a hot muggy day. I changed out air filter, fuel cap, cleaned the master air censor. However, after visiting a dealership read a P0125 code and that is all. We all thought the thermostat is opening to soon. We replaced the Thermostat and Coolant. Reset the computer, and light came back on. I think we are all puzzled. I could replace the ECT Sensor, and reset the computer. About a 3 hour job. Its located on the very top of engine, right behind the Timing Belt Cover. Please let me know your thoughts. Dave

[@TimmyTheToolman]

@@daycinvac Ok, if I ever troubleshoot this code, I'll let you know what I come up with. But, a quick search on this problem pointed to the Air/Fuel and O2 sensors being bad. You can test them but with 420,000 miles, I'd say just replace them. I did that on my rigs just for the chance that it might improve my gas mileage and improve the performance of my engine. These sensors can get "Lazy" and not work as well. Check this video out and make sure to rear the video description: kzbin.info/www/bejne/eaXRmHSMra-roac

[@jacobchandler7953]

Great video. The content was good, the Sound quality and Video were spot on. I had one question about my 2002 Toyota 4runner. My engine light vsc trac vsc off were on, I got the engine code and it was Bank1 Sensor 1 O2 Sensor. I ordered and installed a "Denso" replacement, the lights went off but now I get a stutter from the car. It feels like a loss of power and a hesitation. Would I need to look into the Mass Air Flow Sensor? or tune up post O2 sensor install. "Back Story----->" Sensor was bad for about a month, I didn't have money so I couldn't replace it. Car was a daily 20min round trip driver that ran solid before and during the lights being on. Any help would be appreciated, thanks in Advance

[@TimmyTheToolman]

Glad you like the video. First, I'd just double check you got the correct sensor for your year and transmission. Was this the upstream or downstream sensor? If it's the upstream, it should be an air/fuel sensor and not an O2 sensor. Also, other manufacturers will list the associated Denso part number but the sensor isn't a Denso. Is the one you got a Denso sensor? People have had problems with non-Denso sensors. If you indeed got the right sensor, starting with a cleaning of the MAF sensor sounds like a good idea. With your O2 sensor bad, the information reporting back to your ECU about air/fuel mixtures wasn't correct. Now, with a dirty MAF, you could be running too lean. I'd also clean the throttle body. Don't just shoot the throttle body cleaner in there and let the dirty run-off drain into the IAC because that can cause you more problems. Spray some throttle body cleaner on a rag and wipe out the black deposits on the inner bore and baffle. You can pick up MAF cleaner and throttle body cleaner at any auto parts store.

[@davidweldon8309]

Timmy The Toolman ppl

[@HalloweenMachine525]

Hi Timmy, First, Thankyou for all the amazing videos. I owe you for all the money I've saved. The rear main seal being the biggest job so far. I have a 99 T4R V6 4WD Auto, I'm in Canada and only have one CAT. when on the Denso site you linked should I go for the Exc. Calif upstream and downstream? any Help is very appreciated :) Mat

[@TimmyTheToolman]

Take a look under your hood at the emissions sticker. It might say whether or not your rig was built to California emissions spec or not.

[@NoHandleNameScrewTube]

My front sensor plug is fastened on top of the transmission. Cannot see it. Can’t get to it. Cannot get both hands in. This will be interesting. Okay update... can reach your right hand up over the left trany tail and right thumb will push in the sensor clip. Then pull the sensor side. If you have someone to pull it forward while you press your good. It’s tricky but doable. Thanks for the video help.

[@TimmyTheToolman]

Yeah, I remember it was a pain to get to. Good job gettin er dun.

[@Gunner_0306]

Hey Timmy, love your videos. I have a 19 T4R Pro, 16 Tundra, 1986 T4R 22RTE and a 96 T100. I reference your videos for jobs I haven’t done. I recently got the P0171 code on my T100. I replaced the spark plugs and wires back in November, radiator and thermostat in February, transmission flush in March. I’ve cleaned the MAF and just changed both O2 sensors. Should I leave the code on and see if it goes away on its own? That way I can see if it’s something else?

[@TimmyTheToolman]

The code won't go away on it's on. The check engine light will stay on until you clear the code. Cleaning the MAF most likely fixed the issue.

[@Gunner_0306]

Timmy The Toolman I cleared the code after I cleaned the MAF sensor and it came back again when I did that. I’ll clear out the code again now and see what it does. Thanks again!

[@TimmyTheToolman]

@@Gunner_0306 Well, hopefully it goes away.

[@Gunner_0306]

@@TimmyTheToolman it worked. I cleared the code and so far it hasn't came back on. I could tell the the upstream sensor had more black carbon caked on it and is the one that was possibly throwing the code. Thanks again. -Dan

[@TimmyTheToolman]

@@Gunner_0306 Good to hear you fixed the problem.

[@ianteeley519]

You said it needed to go through 2 tanks of gas before you could tell if it was the right solution... so what was the result? Was replacing the O2 sensors the right fix? My 1997 4Runner I just purchased failed California smog test and the gentleman told me I probably needed new O2 sensors, so thank you for doing this video, it's incredibly helpful.

[@TimmyTheToolman]

My gas mileage improved very slightly after the sensor replacements. Hopefully your rig passes smog.

[@skidaddleskadoodle563]

When cleaning the surface for the o2 sensor, did you cover up the hole or no

[@TimmyTheToolman]

No, I didn't cover it. If you have big pieces of gasket to remove, it might be a good idea to cover the hole so the debris doesn't get stuck either in the catalytic converter or muffler.

[@andyz3925]

Can a leak near(collector area) a Cat cause the engine light to turn on. Our local Autozone guy says its the O2 sensor that needs to be replaced?

[@TimmyTheToolman]

An exhaust leak could definitely be the cause for a CEL code to arise.

[@johngacy6367]

Timmy I finally crawled under my rig to look at my upstream sensor to check the condition of the nuts, turns out the nuts are almost completely rusted out and gone. I might have to get a tap and die set to try and salvage the threads. Any advice?

[@TimmyTheToolman]

Hard to say. If the studs are too far gone, your best bet might be going to a muffler shop so they can weld on a new O2 sensor bung for you. It probably wouldn't cost you that much.

[@johngacy6367]

@@TimmyTheToolman thanks timmy

[@TimmyTheToolman]

@@johngacy6367 No Problem

[@kegcoffeetable]

Good video, I have a 0420 code on my 03 tacoma. Have tried sea foam in every way , crakecase, gas, and air intake . The code came back on though, I'm thinking of replacing the up stream o2 sensor, which read 3.00 vts . What you think, thanks for your advise . Kg

[@TimmyTheToolman]

If the ohms resistance is out of spec for the O2 sensor, then I'd replace it. I do think a P0420 code would be more of an issue with the downstream sensor. If it's neither the upstream or downstream sensor as the culprit, it may be a situation that you have to replace the catalytic converter. But, if it were me, as a last ditch effort before having to replace a very expensive catalytic converter(s), I'd try a product called Cataclean. It's got mixed reviews but maybe it will work to clean out a partially blocked up catalytic converter and allow the code to go away and you can pass a smog inspection and get your vehicle registered.

[@unodfredy]

Correct me if I'm wrong but I looked up on All Data my codes which are P2241 and P2238 for my 03 4Runner sport. Those would be the sensors right next to the manifold on the 4th gen correct? And they're upstream AFR sensors?

[@TimmyTheToolman]

Hey Fredy, I found this link and I think you will find if helpful: www.autocodes.com/qa/51208/what-do-codes-p2238-p2241-mean-for-2004-toyota-4runner-sr5-v6

[@TJAzton]

Excellent video as always! Great job!

[@TimmyTheToolman]

We're glad you think so. Thanks for taking the time to comment.

[@LMichelle_bklyn88]

Should you remove the negative battery terminal first before changing the O2 sensor?? Just saying...

[@TimmyTheToolman]

You could but it's really not necessary for fear of shorting something out. I don't know if one of the wires in these plugs has a 12V constant, but even if they did, you'd have to try to ground it out since the connectors are recessed in the plugs. It would be beneficial though to reset the ECU so the computer will more quickly adapt to the new readings it's getting from the sensor. So, for this reason, disconnecting the battery and resetting the ECU would be a good idea. Thanks for the comment.

[@javivivero5119]

Hi Timmy Great vídeo! The check engine light of my 4runner 96, just turn on, troubleshooting P0420. 1.- Catalytic converter with defects 2.- operation condition o motor fail 3.- vacuum considerable leak. Based in your experience, do you know the probable cause of this code?

[@TimmyTheToolman]

Hey Javi, this P0420 code, like many CEL codes can have many different causes. This code pops up due to the downstream O2 sensor picking up a problem with the exhaust gases it's reading. The sensor is saying there's a problem with the Catalytic Converter Efficiency. If it were me, I'd first try replacing the downstream O2 sensor and see where that gets me. Your last resort is actually replacing the catalytic converter(s) because that's lots of money.

[@javivivero5119]

@@TimmyTheToolman Hi Timmy, thanks for the advise, did you get the oem o2 sensors from amazon? Other thing, I sent you some pictures vía whats app

[@TimmyTheToolman]

Yes, I bought the sensors via Amazon.

[@BrisaHalviatti]

This is perfect! Although I need some advice: Roxanne is an Auto to 5spd swap. So while she has a MT the ECU and harness still believe she's auto. Should I order an O2 sensor that aligns with my ECU or with the actual components in the vehicle? 😅

[@TimmyTheToolman]

Brisa Halviatti do the current 02 sensors have a part number written on them?

[@BrisaHalviatti]

@@TimmyTheToolman too rusted to see :/

[@TimmyTheToolman]

Brisa Halviatti yikes. We’re you the one who posted a thread on this topic recently on t4r.org?

[@BrisaHalviatti]

@@TimmyTheToolman yep! Posted after I commented, I read daily and forget I can ask there too 😅

[@TimmyTheToolman]

@@BrisaHalviatti Get the O2 sensor that aligns with your rig like it was originally built with the auto trans.

[@king49334]

Keep up the good work

[@TimmyTheToolman]

Thanks, we will.

[@billythomas4527]

Hey Tim !! Are you located in Cali ? I got a CEL on and I need new 02 Sensor. The code calls for the Bank 1 Sensor Number 2, so should I swap both ? And would NGK sensors be just as fine ? I am located in Canada. Was gonna use those same 02 Sensor as you since I have a 4WD automatic 99 4Runner

[@TimmyTheToolman]

I would renew both sensors and use Denso sensors since those are OEM.

[@billythomas4527]

@@TimmyTheToolman Timmy. Please help ! I already ordered Part Number 234-4162 from Denso. However I am still looking to get the second 02 Sensor I need. In your video you get the 234-4154 however on the website it calls that it is for the manual transmission. I am confused can I just get the same Part number twice and use them both ? Which one do I need ? I have a 1999 4Runner V6 5VZE Not in California. Please someone help ! My truck started running super rough. Very very bad. I also have a lean fuel trim code AND a knock sensors codes.....Got new plugs just trying to order the other 02 sensor I need. Help !!!

[@TimmyTheToolman]

@@billythomas4527 Does your rig have 4wd? Do you have an automatic or manual transmission?

[@billythomas4527]

@@TimmyTheToolman Automatic. 4WD yes

[@TimmyTheToolman]

@@billythomas4527 Based off what I saw on the Denso website, you would buy the 234-4162 for both the upstream and downstream oxygen sensors. The vehicle I did the video on is a 1998. That's why I have different sensor part numbers. If you do a search for a 1998 with 4wd and an auto trans, you'll see why I used those part numbers.

[@DanKelley83777]

Not what I'm looking for, but I'm looking for a video of replacing the abs censor on 2003 Tacoma front left. Thanks for any help.

[@TimmyTheToolman]

We don't have a video for it but its should be pretty easy. The sensor plugs into the knuckle and is secured with a 10mm bolt. You would disconnect it there and then follow the line up until you can find a connection you can disconnect. If it were me, I'd try to find one at a wrecking yard like PicknPull and grab one off a wrecked 1st Gen Tacoma or 3rd Gen 4runner. We do have a video that shows how to disconnect the sensor from the knuckle. In this video, kzbin.info/www/bejne/Y6S8Y5SwrrF1q6s, go to play time 6:11 and you'll see how we do it.

[@ellechingona339]

OMG I SAW YOUR VEHICLE ON BASCOM AND HAMILTON! YOU FAMOUS BRUH!!

[@TimmyTheToolman]

Well, howdy neighbor.

[@TheWeirdSide1]

The site didn't prove useful for me to find downstream 02.. It only listed a part number for 02 sensor with no plug terminal. I found another denso with pigtail that claims to be the downstream/cali emissions.. But I don't trust anything on these sites..some don't even have a part number. btw, amazon has identical 02 sensors with same part number and they are WAY cheaper than local auto parts stores or other sources, as the video host related. Oriellys wants 105 plus tax, whearas amazon is 55!

[@TimmyTheToolman]

That's interesting the Find Your Part website didn't work out. Both times I replaced O2 senskrs on my 3rd Gen 4runners, I got the part numbers from that site and ordered them from Amzon for the same reason you mentioned.

[@abovethenotchliving2397]

Great video Timmy, very informative, clear and concise. Is there any chance you can buy just the gasket for the downstream O2 sensor somewhere? Or would I need to purchase the whole sensor? I'm planning on replacing the exhaust from the cat all the way back on my 03 Tacoma 3.4l and I'd really like to re-use the downstream O2 sensor because it appears to be in great shape, however I know you're not supposed to re-use the gaskets. If I could just get the gasket that would be great. Thanks

[@TimmyTheToolman]

I don't know if you can buy just the gasket because I've never tried. You could visit your local Toyota dealer and ask them or possibly an auto parts store might carry it like O'Reilly's.

[@abovethenotchliving2397]

Ok I'll give the local O'Reilly's a try. Thanks@@TimmyTheToolman

[@driskolestateshow]

Is Denso a recommended brand? When I look up O2 sensors I see a brand called Moca with quite a few options. And the pricing isn't as much.

[@TimmyTheToolman]

You should only consider DENSO. That is the OEM spec. - Sean