Oxygen sensor - collar around it??

I dislike special tools. This thread is a great example of a car company needlessly screwing over the DIY mechanic.

The Toyota special tool, 09224-00010, is made by OTC and retails for $75!

The OEM 25249 is a 7/8" / 22mm O2 sensor socket that retails for $9.99. This should fit, but as r0b_ found out, it (or one like it) is too big.



I tried the OEM socket today. Too big, doesn't fit inside the collar. But, it is just a hair too big, literally! It only took 10 minutes on my Craftsman hobbyist grinder to take off enough material.



Actually getting a 1/2" drive breaker bar on it will be a challenge. I'm hoping that I don't have to do this anytime soon.

 

So after all that work, did it fix the code? =)

 

Well, I did satisfy my own curiosity, and thought I would share my findings for others that might be faced with this problem. And grinding the snot out of something isn't work!!!

I hope r0b_ was able to make progress.

 

Nice work. Now that you are ready to replace the A/F ratio sensor, you'll probably find that it will last for the remainder of your 2005 ownership...

 

Yup, being prepared with a special tool almost guarantees that you will never need it.

 

I have a similar shield on the O2/air sensors on my motorcycle. The important difference being that there was an ear to the collar on both sides that held the shield in place, remove the two screws on the shield, and it was easily removed to get to the sensor.
What the shield may be, and I am guessing, is just a shield against a rock getting thrown up as you are driving and damaging the sensor. A heat shield kind of doesn't make sense as doesn't the OS sensor work only when it is heated up? Adnd aren't the header pipe and muffler pipe pretty hot on a running car? or are you guys thinking heat shield to keep the heat in on a cold day? When I first read it, I thought you mean to keep the sensor from getting too hot from the surrounding engine bay.

 

they are definately not the same part, if you go to the Bosch website it has the different parts numbers. Also the Autozone and Kragen websites also list different parts for upstream and down stream.

 

I am getting code p0420 and want to replace the air/fuel ratio sensor and cannot figure out who to reach and remove the connector to the sensor. Can somone tell me how to do it? I read several threads about it and saw instructions for the rear O2 sensor but not the fwd air/fuel ratio sensor.

I hope to remove it from below and avoid removing the inverter. From under the car I can see the cable leaving the sensor and I think I see it terminating in a connector on the left side of the engine. I can barely snake my arm up there and touch it, but I cannot get a good enough grip to press a release button and pull it free. I figure there must be an easier way so I decided to ask for help before proceeding.

I got the rear O2 sensor changed in about 45 minutes.

Thanks in advance for your help.

Doug

 

I just finished changing the upper A/F sensor on my 05. Here is what I did after reading many threads...

1. Jack up the car and place on four jack stands so its high ennough to get under.
2. unbolt the lower heat shield on the exhaust manifold ( two 10mm bolts which may be rusted and break off. One broke for me but the other one is enough to hold it in place)
3. Use a dremel tool with metal cutter wheel, snake up the dremel so its parallel with the ground and above the sub-frame. Then you can use the dremel to cut a slit, or L-shape slit in the shield around the sensor.
4. replace the heat shield and Lower the car. the rest of the work is from under the hood.
5. Open the hood and remove the wipers, plastic vent covers under the wipers, and wiper tray (you dont need to remove the wiper motor from the tray). Disconnect wires so it can be removed completely from the car.
6. now you can get this tool from autozone or pepboys on the sensor. (The long silver one only will fit). You need to lay on the air cleaner housing and really get in there.
7. Where the sensor wire clips to the car harness, there is a plastic clip mounting it to a metal bracket, if you unclip it you get more room for the wrench...Use a 1" Open end wrench to turn the O2 sensor socket to unbolt the sensor. The other end will go between the fuel lines and the inverter housing. You have to play with it to get the right amount of room. Also a large adjustable cresent wrench will come in handy since they are shorter and will provide more angular movement in that space. There is also some room between the exhaust pipe and the firewall to use the 1" wrench/adjustable wrench.
8. After the sensor is removed but wire is still clipped to the harness, you can snake it through to the front of the car to access the clip easier and unclip.

Reverse to install (except clip it to the harness LAST to allow it to spin when bolting on).

These steps worked really well for me you just have to get in there to see the space to work with.

 

Driving a 2007 Prius I got a P0420 code and was recommended to use fuel cleaner, replace my spark plugs, replace my engine air filter, replace my O2 sensor, and replace my Air / Fuel ratio sensor first before I even considered replacing my catalytic converter. I was able to do all of that pretty easily, but I was unable to remove my AIR / FUEL RATIO SENSOR (not the O2 sensor) because I didn't want to take out the inverter. I eventually gave up trying to replace the Air /Fuel Ratio sensor as the P0420 code went away, but I am stuck with a new Denso Air / Fuel Ratio sensor and a modified O2 socket (that I bench grinded to fit into the Air / Fuel Ration Sensor heat shield). I am wondering if I should get rid of both of those, or if I should hang on to them. If I did hang on to them and followed Kevin3's above instructions then I have a few questions:

I just want to make absolutely sure that you cut out the heat shield of the AIR / FUEL RATIO SENSOR (not the O2 sensor) while you are under the car?

If so, then while you are over the engine (with the mentioned panels/parts removed for better access) do you take the Air / Fuel Ratio Sensor off with an 1" open-ended/adjustable wrench because there is no longer a heat shield in your way?

If so, then how did you reinstall everything? I would imagine the removing all this would be much easier than reinstalling a new especially considering that you will need to apply some kind of anti-seize and apply the appropriate amount of torque to the modified O2 sensor socket.

Was reinstallation of the new sensor somehow easier? If so, then let me know how. Sorry about the incredulity, but I am not sure what to believe since it seems like it worked out for you as you also had some good tips about the wiring attachment.

 

This is a really old post but anyone looking for the Toyota oxygen sensor socket tool, I've found one from tool source.com for $104.95

Oxygen Sensor Socket - Toyota | OTC - SPX | 09224-00010-01

If anyone knows a place to get one cheaper please let me know, I need to change out my top O2 sensor for preventive maintenance.

 

You don't don't need a special tool for the O2 sensor replacement. All you needs is an O2 sensor socket that you can get pretty much anywhere for $10. The A/F ratio sensor needs a special tool that only Toyota makes or else you can grind down a regular O2 sensor socket until it fits into the A/F ratio sensor heat shield. I replaced my O2 sensor using a $10 O2 sensor socket, and then I grinded the O2 sensor socket down until it would fit into the A/F ratio sensor heat shield. I never ended using either my replacement A/F ratio sensor or the modified O2 sensor socket as all my codes went away with what I had done up to that point, not mention that I couldn't even get to my A/F ratio sensor to take it off let alone to put a replacement A/F ration sensor back on. All I can say is if you really need to replace your A/F ratio sensor (and not your O2 sensor) make sure that you can get to it first.

 

Some of the tools are too thick. So, buy one and use an old fashioned grinder and take a few mils off. I did this and it worked like a charm. I picked mine up from Harbor Freight and modified it a little.

 

I have been a quest myself and I stumbled onto this by pure chance 26 bucks plus shipping, I just ordered it, will update how well it works.
Shielded Oxygen and Fuel Sensor Socket | Schley Products, Inc | 66750B

 

I just replaced my A/F ratio sensor on my 2006 Prius. I ordered the Schley 66750 tool from Amazon ($25) and found that I had to grind off about .150" to get the diameter down enough to fit into the shield of the OEM sensor (1.200"). The depth of the tool is perfect for fitting into the shield and engaging the hex-nut portion of the sensor. Perhaps the 66750(B) tool would work better without grinding (it was $35 on Amazon).
I removed the tray that houses the wiper motor and arms and did not need to move the inverter. Once I got the sensor tool ground down to size, I found it easier to work under the car with it up on ramps.
I heated up the bung with a small MAPP/ O2 torch and the sensor came out with no fuss! I did not need to remove the exhaust manifold heat shield like the original poster.

I replaced my sensor with a Bosch 15974 sensor from Amazon ($100). So far, the P0031 code has not returned.

 

Schley 66750B starts at $33 incl shipping on Ebay. It specifically says for shielded Oxygen sensors as found on Toyota starting year 2003. I may need one, thanks for the reference.

 

Ok, for Those of you who have a welder/torch & grinder/dremel handy, here's a cheap solution.
What you need:
7/8" deep 12-point 3/8 drive (thin wall) socket, 5-1/2" long steel rod or bar.
Measuring from the bottom splined end (that goes on a bolt head), cut the socket to a 1-1/2" long collar. Toss away the top part (drive-end). Using a cutoff wheel on a dremel or small grinder, cut a 1/4"-5/16" notch up the entire length of the socket collar so it resembles a tubing wrench. On the top end of the collar, directly opposite the notch, weld or braze on the "handle", be sure the collar has at least 1-1/4" length from underside of handle to tip of collar so it will fit all the way in the sensor cup.
Raise the vehicle, you can access the sensor below by reaching between subframe & axle, a person with slim arms 28" long to fingertips can reach up between axle & oil pan to undo the connector with zero disassembly. (I did it).
View attachment 117131

 

Found this tool on Amazon: CTA Tools 2064 for $18.85. I have not used it personally, but Amazon reviewers say they've used it to change a Prius sensor.