There is a flat tang the connector attaches to. You must lift the release tab on the sensor end of the connector and slide it towards the sensor to release it from the tang. Once free push the bigger tab to separate the connector.

 

So there are more than one little pivot tab / tang thing for me to pry open in order for the connector to come free?

 

Yes two release tabs. One to free from metal bracket one for connector to wire harness. The one to free from bracket is under the connector one the bracket side. Sorry it is hard to explain on the internet without a pic.

 

Thanks a lot - will report back with details to help future generations once I figure it out!

 

Hi! I am having the exact same problem (complete with shredded hands) and wish you had reported back with more details. Guess I'll just have to figure it out like you did!

 

After much searching, I finally found a similar situation with a photo at the following link:
E-130: DIY-Oxygen (O2) Sensor Installation - Rear Upstream A/F aka P2251 - AcuraZine Community
In case the link changes, the relevant part is copied here:


Quote:
Remove the old O2 sensor
5. Find sensor - it's located in Bank 1 of the engine, on the passenger side, between the engine and firewall. You'll see it - trust me. The sensor is pointed towards the ground, with wires pointed in the air.
6. The sensor unscrews with an O2 socket wrench, or (if you're lucky like me) a large adjustable wrench. A socket wrench or adjustable wrench will fit down there, so lean against the passenger fender (cover it with a workmat if you have one), and get your head and arms in there. Some (like me) had better luck with a warm engine, but it's just an option. Lefty-loosey...and once you get some give, don't unscrew it all the way.
7. Now unclip the harness - there are two mounting points, (i) a piggytailed clip facing the engine, and (ii) the standard O2 sensor harness clip facing the cabin. Do the one facing the engine first - push the metal piece away from the harness, towards the engine, and slide off the O2 sensor harness off the piggytailed connection. Now that the harness is free, you can easily unclip the harness. Unscrew the rest of the way, and remove.
* Unfortunately, I spent the most time on this because I didn't realize there were two clips holding it to the car. Once I removed the piggytailed connection, the other one was easy.

Unquote

I know this is not exact, but it gave me a good enough idea to get mine loose after a few hours of trying! After that it's easy, and the car is running better, the CEL is off, and passed state inspection. Probably improved mileage as well! BTW, wait at least 100 miles before getting inspected or the computer will say "Not Ready" on the F/A sensor reading.

 

That picture really helped me out - it seems to be almost impossible to unplug the oxygen sensor without removing it from the bracket. I was pushing down on the rotten tab for some reason, but once I saw the pic it made sense and it came right apart - once you have the two connectors free from the bracket, they come apart easily (I thought they were bound up with dirt, but that was not the case)

van started throwing P2251 and P0134, so I was thinking maybe a bad connection. The cables look fine, and both connectors (engine harness and oxygen sensor) looked good - I cleaned them out with connector cleaner just the same, dried them out and remated them - we'll see if the code comes back. If it does, the sensor needs replaced, I guess. (for a while, the car would throw P0420 or the combination above, but my wife said it was usually after hitting a bump on the highway, so I thought maybe a bad connection. If it's not there, I shudder to think how fun it's going to be to chase down a pinched harness somewhere else in the engine compartment...

 

I found this helped a lot:

1) Study the new sensor - note the location you need to depress to release it from the metal tab.
2) No the bump on the other side, this is where the the other 1/2 of the connector latches.
3) The biggest help for me was to unplug the front pre-cat sensor. That way you get to actually see/feel how the sensor gets release from the tab and how to separate the two halves.

 

Well, codes are back so I ordered up the replacement sensor. bummer. On the bright side, it looks like getting it out shouldn't be too much of a chore.

 

Borow a crowfoot O2 sensor wrench from some place like AutoZone if you can. With the right tool the hardest part of the job is getting to the electrical connector.

 

Oh - I am all set for tools (I have an offset oxygen sensor socket as well as a tall inline sensor socket (I actually prefer the latter, as it's less likely to rock off the sensor when cranking on it)) - as long as the threads aren't too badly bound up, it should come right out (I'll hit it with a little pb blaster and let it sit for a bit before I put a tool on it) - on other cars I have worked on, it's been more of a challenge access-wise (the front sensor on a 2.0L WRX is an example - it's in the exhaust manifold, and is angled a bit, so access is very limited.

 

That had to be the easiest oxygen sensor removal I have ever done! No penetrant needed or anything, it just came right out! I ended up using an inline (tall style) sensor socket - I think access is actually better for that. I removed the center coil pack (otherwise the socket would have rested against it) and it came right out. I checked the front sensor to see if it was held in there similarly, and it came loose easily as well. Torque spec is only 33 ft-lbs, and it looks like they actually had it torqued to spec! The new sensor came with anti-seize on the threads, but most of it had fallen off in the bag so I re-applied some (if anyone else is doing the same, make sure the stuff you use is marked sensor-safe - otherwise as the carrier burns off, or if you get some on the sensor head and it then burns off, the decomposition products can damage the sensor element)

Hoping the sensor fixes the codes and it isn't damage elsewhere on the wiring harness! (I figure at 172k miles it's pretty normal to have an oxygen sensor go south)

 

DrD: Did the CE light go off?

I was having trouble with the connector for the front pre-cat sensor: just pried it off, tearing off a side of the connector. Nylon-tied it back onto it's tab.

 

I just replaced this sensor on my 05 Touring last night. I probably would still be trying to get the plastic connector to release had it not been for this thread!!! Thank you so much! It is exactly as mjody said above. You have to press the release and slide the connectors towards the passenger or sensor side before they will disconnect from each other. After that, it was downhill. Cleared the codes and so far so good!

 

My sensor came out so easily I thought it was finger tight.
That connector... stupid hard. I got it off the holder from below then off its mate from above. I have tools for just such things (18" long bent needle nose, extended vise grips about the same length) but they werent much use cuz you cant see when your hands in the way.

 

THIS! THIS RIGHT HERE IS WHY I FREAKIN' LOVE THE INTERNET! After over an hour of pushing in that top tab and pulling down with no results other than torn up arms I found Jambo1's post that showed the front clip that you had to do first with the sideways slide. BOOM! Totally got it! Totally saved me some bucks and time without my car! Thanks so much for posting this, you have done Ody owners a great service!

 

I have an alternative solution borne of pain and frustration.

The first connector that must be released is a pain to get to release. We are working blind. However, the metal tang that this connects to is part of the connector to the Oxygen sensor itself, not the harness.

Assuming the objective is to change the O2 sensor (and not to test the sensor), the plastic part of the connector that connected to the metal tang is going to be replaced anyway. Use a screwdriver to destroy the plastic connector next to the metal and out pops the connector.

 

Resurrecting this old thread. This effing connector is driving me nuts. Any additional tips? It appears the tab that disconnects the connector from the metal bracket is on the bottom, correct? Does this tab need to be depressed toward the passenger cabin, or pulled out toward the grill???

Edit: I got it!!! The tab is on the engine side of the clip, on the bottom on the clip. I had to depress the tab toward the cabin, and then push/pull the clip down toward the ground and off the metal bracket. This is what threw me, because I read either here or elsewhere that the clip needed to slide off toward the passenger side, but for me it had to slide down. Good luck to anyone else trying to do this!

 

GLee is correct. On my 2007 exl, the O2 sensor connector was difficult to remove. I was depressing the tab and pulling down (towards the ground). It’s not going anywhere because the O2 connector is mounted to the metal bracket/tinge/mount. I found that if you get a small screw driver and slide it up (away from the ground) through the tab, you can push the female connector up off the O2 connector. The O2 connector will be left on the metal tinge/mount. At that point you can depress the tab and pull down the O2 connector off the metal tinge/mount.