DIY : changing the Oxygen / O2 sensor on Yaris hatch MANY PICS

[auxmike]

This is just a pictorial of what you will see and what I used to do the job. Do this at your own risk! You can get burned and really screw up your car trying to remove these parts. If you get stuck, you may need to hire a mechanic to to fix your mess, $$$.
I was able to successfully change out both my AF Sensor and the lower oxygen/O2 sensor. I learned real fast that doing this with cold pipes is futile. Upon running the car and getting things hot the job moved quickly.
I started by trying to remove the lower sensor with a cold exhaust and it turned about half a turn even using a large pipe wrench AND a floor jack to push up on the darn wrench! It would not turn.Period. I tried again the next night with a hot exhaust and spraying some WD40 on the point where the sensor meets the threaded bung. I rocked the tool back and fourth as I got it to start turning while continuing with little shots of the WD40. It was SO much easier with a hot pipe! There are pics showing how bad the threads were stripped on that lower sensor, damage from working with a cold pipe and almost snapping off the sensor... The sensors connector plug is INSIDE the car, you will need to remove the center consol to unplug it and feed the new wires in.
The top one was done using the same technique. That one was EASY. I only needed a 3/8 drive ratchet with the shorter cast steel tool to crack it loose. After hearing how members trying to remove these top units were unable to, I wonder if they used heat to open up the threads first, or if I got REAL lucky taking the risk getting it out without hiring a mechanic.
There's a black metal plate that's bolted onto the engine just above the axel boot. Remove the nut from the right side and the bolt from the left side using a 12mm dep socket. I used a 1/4 drive no problem. If you don't remove this plate first don't bother attempting the job.
I've added many pics. Some show a few variations of tools you can use to turn that stubborn sensor. Having them all lets you switch between them as needed. WD40 is a lot better than it gets credit for. After I started the car there was some smoke coming off the pipes as the lubricant burn off.
I was super happy with the results!

[auxmike]

#2

[auxmike]

#3

[auxmike]

Notes;
Denso is OEM evidently, Not NGK/NTK. I thought otherwise.
Sensors cost: Top. $160, Bottom $125. Not cheap but 100% correct with proper wire lengths and fantastic quality. Don't buy the generic one that requires splicing. Pennywise, pound foolish. I like going the cheapest route too, but that top sensor is a super important part and if it's not just right a CEL might go off and you won't be happy.
THe sensors both have 50,000 miles of service. The grey one is from the top. They look pretty good after all those miles. No black soot. I've never seen such a clean set before! Guess I'm not burning oil, LOL! You can't see the fasteners on the black metal plate, but I shoved the camera up into the engine so you can. I used rhino ramps, NOT a jack. I did'nt disconnect the battery, but it's probably safer to. The sensors come pre coated with anti seize. 22mm is the socket size. A 7/8 inche wrench should work too. Don't use a hammer!

[yarisugi]

Thanx for DIY. I didn't know there was a special socket for that. May I ask why you replaced them? Was it because of a check engine light problem?

[auxmike]

No check engine, just a fanatic owner. I figure after 50K of burning Hell the things might be getting a little tired. I used to change my Saturns single wire Sensor every 30,000 mlies. Always with the $56 dealer part too. My old '97 Saturn had a recurring light for both sensors. Car ran kinda bad too, not much power. Well, I found both the sensors for $49 the pair shipped on Ebay! The bottom was Bosch, the top some other brand. Both with exact fit connectors. I saw no point in buying OEM for a 15 YO car with over 170,000 miles on it. The car has so much power now, like new!
I'd say leave the bottom Yaris one alone after seeing how nice mine looked. That is unless you get a specific code for it. The top one is worth swapping out to keep it running smooth with good power and MPGs. My butt dyno swears the car feels "faster" too....

[Klink10]

Thanks Mike for posting with pics and info.

[auxmike]

It's my pleasure!:thumbsup:

[jaherrera1]

my english is bad.

My yaris (TOYOTA YARIS (NCP90L-AGMRK)) have code P0031 HO2S Heater Control Circuit Low (Bank 1 Sensor 1). it has two oxygen sensors, which one should I replace according to the diagram below ...

http://www.toyodiy.com/parts/p_G_200711_TOYOTA_YARIS_NCP90L-AGMRK_8401.html?hl=89465A

which one is Bank 1 sensor 1... the part number 89465-52370 or 89465-52380 number

[jaherrera1]

which of the two shown in the photos is the bank 1 sensor 1 ... the one with the blue in the middle or the other

[jaherrera1]

please sombody help me, here in venezuela nobody knows which of the two shown in the photos is the bank 1 sensor 1 ... the one with the blue in the middle or the other

[auxmike]

I think the top one would be sensor 1. Neither of those part numbers matches the ones I have in my pictures for my 2008.

[auxmike]

Don't forget to chock the wheels....

[dfhnpdx]

OEM Denso sensors are $61 and $97 at RockAuto.com...+ 12 for shipping...Dont pay dealership prices...

[BMGYaris]

the wide range O2 sensor-aka the air/fuel sensor- is bank 1, the one found up front just under the engine. Pep boys wanted 250 for the sensor and 200 dollars labor. Thanks to these pictures I got the sensor for 119 from advance auto parts, rented some oxygen sensor tools-for free-and got the job done in about 15 minutes of actual hands on work. Note, my bank 1 sensor was super easy to pop off, right away with like a 3 inch long socket wrench (not much torque at all). hardest part for me was disconnecting couplers, but it wasnt too hard. Ha, 200 labor. Will never go to pep boys again.

[JarHarms]

auxmike, thanks for the write up and tips!!
I just changed the front O2 sensor in my '07 hatch while I was under there doing the oil/filter change. Maybe took an extra 15 minutes. Removing that axleshaft shield improved the working room. I did not have the fancy offset sockets but was able to use a 22mm box/open wrench. Although there was not much room to swing the wrench so next time I'll get one of those sockets. The exhaust was sort of warmed up but luckily the sensor loosened right up and had no stripped threads. :w00t:

My '07 and the original O2 sensor has 160,099 miles on it. The mpg isn't what it used to be and well beyond the winter blend fuel change. So if this sensor really has a 50,000 mile service interval, I may see an improvement. I'll be checking the next few fill up to see if that is the case. Used the Denso direct fit sensor rather than the Toyota boxed Denso sensor, they are identical except for the etched printing on the sensor bodies. $103 shipped from Rock Auto was easier to justify than the $120+ Toyota one.

[auxmike]

Glad to hear it!

[Hard_Yaris]

in my 2007 yaris sedan i replaced the o2 sensor with little effort... i found removing the battery helped.

I used a long handle 1/2" driver with an 3" extension in conjunction with the special o2 sensor tool. the 4" extension was a bit too long which caused the driver to push against the clutch cable, but i had a 3" impact extension that worked great.
I did but a small amount of anti seize on the oz sensor threads.

[Hard_Yaris]

OK... HELP please..

I am still getting the po420 code after replacing the sensor closest to the motor. Right away I noticed the increase in performance... then i tripped the code again...so

Do I have to replace the second sensor as well...? My car is at 160,000Km. original exhaust... what should I do to fix the code?

[Melloreel]

I can't help with the codes! But I did want to note that my first taste of sensor hell was with an 04 rav4. I was not aware of the term "disimilar metals" until then. All the lubricant in the world will not unweld the two metals hence stripped threads!
I was going to take it to dealer for repair, but being mr handy I chose to replace it myself. This is when the nightmare started. Spent hours trying to break sensor loose, then when I did it just spun in the hole. Long story short. Had to weld a threaded plug back in header. Asked dealer what he would have done if he stripped it? He said replace header, and charge me for it. Said it happens all the time? Oh! 900 to replace header. Why does'nt factory put never seize on?

[SignPirate]

I got 75000+ mi on my 07 hatch no wonder why the exhaust stinks. Guess ill be changing those out next oil change. Thanks auxmike for your VERY helpful post/pics.

[auxmike]

It's my pleasure. That bottom one was real stuck in and the threads got a bit chewed up. The top one came off with very little effort..

[I_Love_My_Yaris]

Hello

Auxmike, your car is petrol, right ?
I have a diesel, D4D, so the O2 sensor is in the same location ? In my case is only one or two ?

My problem is that my little bug is takeing 10-11 l/100 km......like duble. I tested itt but are no erors. I suspect the O2 sensor to be responsable for this. What do you think ?

Thanks

[auxmike]

I'm not familiar with the diesel since we don't have them in the USA .
I honestly don't know!

[sperginjm]

How did you remove the center console on the yaris to disconnect the down stream o2 sensor

[auxmike]

If memory serves me well you first unscrew the console where the cup holder is at its rear by the handbrake. There's a screw or screws in the bottom of the cup holder well. They may be covered by a felt disc. You remove those. Then you need to lift up/pry that plate that has switches in it so as to let it pass down through the console she'll or you may need to remove the wire harness plug from each switch. Then you just tip up the console a bit from the rear and pull back. There's two pins in the front , so when you pull back they come out of their holes.
I haven't done this since the DIY review and am going from memory only.
Let me know how you make out😇

[Cigar_Maverick]

My "New to me" 2007 Yaris 5 SPD manual Trans hatchback has a check engine light that indicates the O2 sensor needs replaced. The car has 106,000 miles on it. Would it just be good practice to change both the O2 and Fuel/Air sensor? Rock Auto has the DENSO 2344069 Downstream for $58.79 and the DENSO 2349052 UPSTREAM for $84.79. O'Reilly Auto Parts has a tool loaner program that includes the sensor wrench. Provided I heat up the engine, it sounds like a straight forward project. Just need your expert opinions on replacing one or both. I have no idea if the previous owner had replaced either, ever.

[WeeYari]

That's pretty early for an O2 sensor failure. Sorry I have no advice as I've not had the need to tackle the job.

I personally would have made the purchase deal contingent on that issue being taken care of.


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[Cigar_Maverick]

I personally would have made the purchase deal contingent on that issue being taken care of.

As usual, my hindsight is 20/20

[WeeYari]

Have you cleared the code to make sure it is truly a reoccurring failure?

[Cigar_Maverick]

Have you cleared the code to make sure it is truly a reoccurring failure?

I have not. I can take it back to the parts store to clear unless there is a way to do it at home?

[WeeYari]

unless there is a way to do it at home?

Only with an OBD scan tool.

I usually will do a reset to make sure a cel was not triggered by a hiccup before I spend my cash.

[Cigar_Maverick]

Only with an OBD scan tool.

I usually will do a reset to make sure a cel was not triggered by a hiccup before I spend my cash.

I'll give it a shot. If I get the error again, I'll replace both.

[WeeYari]

There is also a thread on here somewhere documenting the case of a member with an issue with the one of the O2 sensors. Problem was a broken or mouse chewed wire!

Also, the code will point to the exact sensor (upstream or downstream O2) issuing the fault. I would only replace what the code indicates and not other stuff just for the hell of it. Sensor failures are rare at 106K miles.

[Cigar_Maverick]

Being a new owner to the car and not knowing it's history, I was just going to err on the side of caution and replace the sensors. However, I'll get it reset and drive it a tad more.

[Cigar_Maverick]

Took the car out and warmed up the pipes on the 2007 Yaris. Got the O2 Sensor and Air/Fuel sensors removed pretty easily. Bought DENSO sensors from Rock Auto. The O2 sensor in PN 234-4069. The O2 sensor looks a LITTLE different. Just want to be sure I'm ok to install it in the morning. See the picture below of the old/new O2 sensor:

http://i1191.photobucket.com/albums/z461/rmorman1/2007%20Toyota%20Yaris/200720Toyota20Yaris20O220Sensor.jpg (http://s1191.photobucket.com/user/rmorman1/media/2007%20Toyota%20Yaris/200720Toyota20Yaris20O220Sensor.jpg.html)


On an unrelated note, when I took the console out, I saw these unused wires. This car does not have a lot of options, so I was just wondering what these would have been for. Power lock/windows?? see below:


http://i1191.photobucket.com/albums/z461/rmorman1/2007%20Toyota%20Yaris/01ec0282-3849-4ea6-a544-bdde3afb3ab0.jpg (http://s1191.photobucket.com/user/rmorman1/media/2007%20Toyota%20Yaris/01ec0282-3849-4ea6-a544-bdde3afb3ab0.jpg.html)



Also, I assume I use all of the lube on the threads that came with each sensor? Can't use TOO much can ya?

THANKS!
Russ

[07liftback]

...

On an unrelated note, when I took the console out, I saw these unused wires. This car does not have a lot of options, so I was just wondering what these would have been for. Power lock/windows?? see below:
...

Looks like it's for the power locks. My Yaris came with power locks and the master switch is right next to the hand brake and shifter.

I just did my oxygen sensor and although it seemed impossible to reach from the top at first, it was MUCH easier getting at it from the front rather than crawling under the car. The only reason I got under the Yaris was to spray the PB blaster on it since I couldn't see what I was spraying when hovering above it.

Using a 3/8" drive ratchet and a oxygen sensor socket, I wasn't able to get leverage either above the car or below it so I had to attach a "cheater pipe" on the handle. It's basically a metal pipe from an old bedframe that I place over the ratchet and was able to get superb leverage without kicking or hammering the ratchet. I could probably use this cheater pipe without the PB blaster prep and still do okay.

Anywho, does anyone know if it's absolutely necessary to reset the ecu by unplugging the battery or will the car relearn the readings from the new oxygen sensor? I will continue without resetting the ECU to see when my MPG will finally improve.

[Cigar_Maverick]

Anywho, does anyone know if it's absolutely necessary to reset the ecu by unplugging the battery or will the car relearn the readings from the new oxygen sensor? I will continue without resetting the ECU to see when my MPG will finally improve.

Honestly, I'm trying to remember if I unhooked the battery or, more likely, went to the local parts store and had them clear the errors. Almost certain I just had the codes cleared. No errors since.

[07liftback]

Honestly, I'm trying to remember if I unhooked the battery or, more likely, went to the local parts store and had them clear the errors. Almost certain I just had the codes cleared. No errors since.

Did mpg improve right away?

[Cigar_Maverick]

Did mpg improve right away?

Unfortunately, that is hard to say... The weekend I put the new one in, I also switched to Mobil 1 synthetic Advanced Fuel Economy, put a new air filter in and new plugs. I had just bought the car and didn't know the maintenance history. The total gained me 2.5 MPG. Going from 37.5 to 40. I am led to believe that, in my situation, the new sensor has minimal effect. That having been said, as they say, your results may vary. In hindsight I might have done a more controlled experiment, but I just hammered it all out at once. Maybe somebody else can chime in who has more experience with just installing the new sensor.

[MUSKOKA800]

Any gas mileage improvement found after replacing one or both sensors???

[07liftback]

Any gas mileage improvement found after replacing one or both sensors???

Mileage improvement should only increase if replacing the oxygen sensor before the catalytic converter. The second oxygen sensor after the catalytic converter only tells the computer that the catalytic converter is still functioning but will not adjust air or fuel mixture.

That's why the first oxygen sensor is often referred to as the air fuel ratio sensor.

[CB900F2]

Hey all..

I decided to check out my Air/Fuel sensor and based on the service manual inspection page(EC-18) From terminals 1>>2 it should read approx. 1.8 to 3.4ohms, mine read 2.8 ohms, but when I check terminals 1>>4 it should read approx. 10K or > ohms, but I read open.. No reading.. I am not throwing any engine code, so its seems odd to me..

Does anyone have a spare sensor they are also measure and see what you get on the 1>>4 terminals?..

I get about 490KM on approx. 38 liters of gas.. I drive pretty hard , and that's about 7.7L per 100KM.. which seems OK...

Any thoughts ?

Thanks guys!

[CB900F2]

Anyone ? :iono:

Hey all..

I decided to check out my Air/Fuel sensor and based on the service manual inspection page(EC-18) From terminals 1>>2 it should read approx. 1.8 to 3.4ohms, mine read 2.8 ohms, but when I check terminals 1>>4 it should read approx. 10K or > ohms, but I read open.. No reading.. I am not throwing any engine code, so its seems odd to me..

Does anyone have a spare sensor they can also measure and see what you get on the 1>>4 terminals?..

I get about 490KM on approx. 38 liters of gas.. I drive pretty hard , and that's about 7.7L per 100KM.. which seems OK...

Any thoughts ?

Thanks guys!

[zerosl]

Darn, I got the p0031 error code as well after I replaced my donut gasket.

Did anyone confirm which sensor as corresponded to this code?

[Teddy Thornell]

I have a 2012 Toyota Yaris 5-door and could not for the life of me find the location of the downstream O2 (Bank 1/Sensor 2) wire harness. Remove the center console and pull back the tab of carpeting in the front. The "plug" is located right there (see pic). The harness comes exits the body of the car on the side of the metal that the plug part is mounted on. Hope this saves someone time....

https://drive.google.com/open?id=1vBIwYqZbUHyctc_golf9Tv-hZ1Ssq6v0

[EricC]

I have a 2012 Toyota Yaris 5-door and could not for the life of me find the location of the downstream O2 (Bank 1/Sensor 2) wire harness. Remove the center console and pull back the tab of carpeting in the front. The "plug" is located right there (see pic). The harness comes exits the body of the car on the side of the metal that the plug part is mounted on. Hope this saves someone time....

https://drive.google.com/open?id=1vBIwYqZbUHyctc_golf9Tv-hZ1Ssq6v0

Hey! I'm about to embark on replacing this sensor in my 2012 Yaris. Your photo didn't post, can you try it again?

[skuff33]

Anyone ? :iono:
Sorry to resurrect this thread but in the event it helps somebody I also got open readings on pins 1 and 4 for both sensors, new out if the box from denso.

[2007yarishatch]

I think I'll remove mine, clean it with a wire brush, and reinsert it

[komichal]

Just sharing my experience - recently I received error P0420 which indicates deteriorated catalytic converter. The light came back a few days after I erased the code. 2007 car with 172tkm (107t miles). I decided to change the O2 sensors as I learnt that they should be preventively changed in 160 tkm due to their laziness they build over time.

After the change the error is gone and the car is considerably more agile. Both Denso direct fit sensors together cost some 130 USD here. The upper one went out quickly while the one down the cat was a bit harder. Still - I used the WD40, a special nut, ratchet and a piece of pipe and it went off, even from a cold exhaust pipe. I was getting ready for some serious battle (even bought a torch for this) but in the end it was not necessary. Yay!

Btw I do not think that cleaning it with a wire brush is a good idea. The sensor is inside a metal cap, you can never reach it with the brush. And even if you do - you will destroy it.

[fazil]

i recently changed my 2006 Mk2 Yaris 13. Terra (120.000km) upper side oxygen sensor.

The engine light was on for the last 5 years and checked with the service, confirming it was faulty oxygen sensor. Toyota dealer asked around $300 for the change.

Then after tons of research i bought a matching Denso sensor (DOX0109) that was similar to the original one without the socket. It had bare wires and connectors inside. You need to cut the existing socket and swap it on to the new one. Even the wire colors are the same.
I put it and yes, it works perfectly.

It all cost around $45 Now the fuel consumption is as good as new. Like 1-2 litre/100km difference with the new one.

So take it as a spare if you find. You'll need it.
Also the car had emission problems, i hope it's also fixed. I'll see in the next inspection.