Downstream O2 Sensor removal issues

[prico82]

So I am having trouble removing the downstream O2 sensor (after cat) on my 2002 Camry, 4 cylinder SE, 140,000 miles. I was hoping someone could give me some pointers! I want to be cautious because I want to remove the sensor, but want to reuse it.

I have 2 issues:
1) Unscrewing the sensor from the exhaust pipe: Tried this after a long drive (parts were hot), but it still wont budge. I am scared that putting too much force on it may put adverse stress on the corroding exhaust system. Definitely seized shut. Would spraying WD40 or other lubricants render the sensor useless?

2) Getting the connector off:

The red circle above shows a metal part that the connector sits on. Do I simply slide the connector off to the left or is there something else that needs to be done? I'd hate to pull it off and not be able to put it back due to me breaking something.

After removing the connector from this metal holding plate, how do I disconnect the male and female connector ends? Is there a release of some sort near the top of the connector (blue circle), or should I simply pull on it? Again, I am trying to avoid braking anything.

I'd greatly appreciate any help or insight. I have the Haynes book, and didn't see any details regarding any of this.
Thanks

[untitlejk]

I just went through alot of time under my 08 Camry after installing headers and as far as the 02 sensor goes:

1. use the WD40. It will not damage the sensor. I heard there's something better called PB Blaster. just make sure you're turning it the right way, lefty loosey righty tighty

2. most harness plugs usually have a small tab that you push down. find that and it should come right off. use a flashlight

[gdanaher]

The thing in the red circle baffles me. I have never seen that. See if it will slip out and then you can depress the tabs on either side of the connector and pull it off.

I am fond of Liquid Wrench for something like this. It comes in a bottle that will dribble on to the threads. More of a penetrating oil than WD40. Let it set for some time and do all of this when the engine is cold. Hot metals expand, and cold metals contract. If it is still stuck, get some ice and chill the areas around the thread. Any contraction at all could help break the seal. Or, living in Pennsylvania, wait until January to work on this.

[SimonRage]

Originally Posted by gdanaher

The thing in the red circle baffles me. I have never seen that. See if it will slip out and then you can depress the tabs on either side of the connector and pull it off.

I am fond of Liquid Wrench for something like this. It comes in a bottle that will dribble on to the threads. More of a penetrating oil than WD40. Let it set for some time and do all of this when the engine is cold. Hot metals expand, and cold metals contract. If it is still stuck, get some ice and chill the areas around the thread. Any contraction at all could help break the seal. Or, living in Pennsylvania, wait until January to work on this.

I can back this one up... first, get the engine warm (not hot) and buy a penetrating lubricant from the auto parts store. Brand isn't that big of a deal... just make it's a penetrating lubricant (heh). Spray a good amount on there and wait.

The light heat will cause the metal to adjust a bit as it cools - which will help further draw the lubricant in. On my Jag, I spent about an HOUR trying to muscle the damn thing off. Then, I tried the approach above and could literally back it off by hand. Give it a shot and let us know how you get on.

P.S.
Every drop of lubricant that gets on the exhaust will smoke when you fire the car back up and it gets to temperature. You can't avoid that, but it'll all burn off after the first drive.