How do you remove this 02 Sensor adapter/plug/connector?

I will be trying to remove and replace an 02 sensor. I was trying to get a jump start tonight and at least unplug the 02 connector. I have been trying (embarrassingly) for the last 30 plus minutes.

I know the grey part in the red circle gets pushed up but thats it. All the replacement 02 sensors I have have an end connector the size of the yellow circle. It looks like that is one big piece on the current one.

Anyone know how to remove this? Thanks

The white color piece has a tooth that is showing through in the center of the upside down U shaped part of the black piece. I’d try pulling up on the white piece until the tooth is just touching the black part, then prying the black part forward, away from the white piece and pulling up on the white piece.

Could be completely wrong, as usual.

1 Like

I see it now, Ill give that a try.

:smile: lol

With the new sensor in hand, it should be obvious how they come apart and if you have difficulty it will be easy to see what pieces are safe to destroy because they are part pf what you are throwing out. Plastic connectors are the bane of my car fixing experience. I didn’t grow up with them and they grow brittle with age and in the cold. I no longer have the keen eyesight I had before 60 and I think to two connecters should be always made of different colors so you can tell what is part of the male and female ends.


Excellent idea to make the assessment with the replacement connector in hand. Without a photo of that … hmmm … that white tooth sticking up looks to be what you need to overcome somehow. Either you press the tooth down, or you pry the black part up and over. Or some combo of the two, enough to allow the black part to clear the white tooth as the connector is backed out. Be sure to take a look at the other side of the connector too, b/c there may be another white tooth poking out on that side. A small dental-type mirror might work for seeing back there. Usually to get the two parts of the connector to budge apart, some sort of prying action is required at first, as they tend to get stuck fast together over time. Sometimes it just isn’t possible to disconnect some connectors without breaking them. If you think you may be facing that problem, try to break the side that you are replacing. If you break the side you are wanting to keep, usually that’s not a show-stopper, but you’ll have to go to the dealership for a replacement.

1 Like

That did help. I can now see how it is held on. Still can not get it off though :smile:.

Here is me tinkering with it :laughing:

This is the new plug. Those two protrusions in the center on both sides are solid, so I guess the piece that goes over that has to be lifted.

Thanks guys

Success. It is the small hump in the O2 Sensor side of the harness at around 5:47 in the first video. You have to use a flathead and pry the engine side of the case over that hump. I did crack the edge of the casing, but it still snaps into place.

In the future if you are working when it’s really cold, warm up the connector with a hair dryer. You don’t need to get it so hot that you can’t handle it, but if it’s warmed up it’s more flexible.

1 Like

Yeah I think its easier if you don’t have gloves on so you can get a grip. Like you found out, I just take a very small screw driver and slip it under the tab enough to clear the locking tab and pull on the connector at the same time until it clears the tab. I’m sure there is a professional tool out there used for this.

1 Like

Good for you OP for sticking with it and removing that stubborn connector. Thanks for letting us know how you finally got it free. Best of luck.

1 Like

Good idea but I do not have any outlets nearby. I do have a 100 ft. 12 gauge extension cord, have to check if a hair dryer is in spec to use with it and if it reaches my car. Thanks

So I did end up replacing the 02 sensor. Used some PB blaster at first and nothing. Then used a propane torch for 2-3 minutes and it came right off with a shallow 02 sensor socket and an 11" 3/8 breaker bar.

Now the problem came with the new sensor not screwing in but after a few tries over a few hours I got it to screw in. I hope all the handling of the sensor did not damage it. I have read that you literally can not touch the sensor tip with anything ( I had it on the ground, in and out of the exhaust and got a spec of antiseize on it). Only time will tell. Cleared the codes and drove it for about a half hour. Will get a drive cycle in tomorrow.

Shops have a special tool that cleans up the threads for that problem. Called a thread chaser. Other posters here have suggested absent a thread chaser to make your own using the old part or a bolt of the same size and pitch, and file a small notch at 90% to the threads which creates a cutting surface, and use it to clean up the internal threads. I’ve never tried that but it seems like it would work pretty good.

The most common cause of contamination failures for O2 sensors is RTV (silicone rubber). A diyer’ will use that type of sealant somewhere upstream of the sensor – even as far upstream as the intake manifold I think can still cause a problem – and soon the O2 sensor fails.

1 Like

George, for many years now there have been sensor-safe RTVs

And they’re clearly marked as such

Are you using bathroom RTV on your engine? Automotive RTV is not a common cause of oxygen sensor failure.

1 Like

fyi, here’s a few links on the o2 sensor contamination subject

That first tech tip bulletin is from 1991, back then we had to be sure to use RTV for modern oxygen sensor equipped vehicles. All of the RTV that I have been supplied with in the last twenty five years has been oxygen sensor safe.

I don’t see many O2 sensor failures, I don’t believe RTV contamination in the repair profession is “common”.

The 99 cent stores still sell red rtv in a small tube. It says it’s for automotive use, and it has a STRONG odor. I suspect it may not be “sensor-safe”

As far as the manufacturer, it’s not anybody I had heard of before

But I agree that failed sensors, due to rtv contamination is not common

1 Like

Twenty years ago Chrysler/Mopar began using a new differential RTV, red/orange in color, specifically designed for use with 75W90 gear oil, it has a strong odor. Differential RTV would be the wrong product to reseal a timing chain cover, if mechanics must be warned about this there is a problem.

1 Like

The 99 cent store RTV is so generic, it wasn’t very specific, except that it was supposedly for automotive use.

No further information. No mention of gear oil and/or differentials

Aren’t 99 cent stores . . . and the various spin-offs, such as the dollar store . . . the kinds of places that sell motor oil that is not suitable for modern automotive engines?

I seem to remember we talked about this a few years ago . . . ?

1 Like