Welding 2nd O2 Lambda sensor hole shut

[S1Driver]

I'm tired of plugging the second o2 sensor every time I swap CAT's (because I'm lazy) so I just need a simple answer to a simple question. Can the sensor stay in the engine bay and not throw a engine light because now it feels it's not getting air, tripping it into thinking it's not working? Please read the question again, understand which o2 sensor I'm talking about, I don't want suggestion about the spark plug method, I don't want to hear about the [̲̅$̲̅(̲̅5̲̅)̲̅$̲̅] spacer, I just need to know if lambda will work plugged it sitting somewhere in the engine bay not giving me CAT efficiency codes. The reason I'm asking is because once I tack it into place it's 4 life and I don't want to find the hard way. I feel like I already know the answer but I just need to make sure from experienced DIY masters This will make my life easier not reaching for the 20-22mm wrench every time I feel like swapping.

[jakermac]

The DME will report an O2 sensor fault code if it sits in free air while the engine is running. And it won't happen instantly. The DME will have to see a few driving cycles before it reports the code.

[Dubbedown]

^^whs

Curious why do you swap cats?

[S1Driver]

Alright thanks for the quick reply. Daaamn it, I firmly believed it will work perfectly but I'm glad I asked first since once welded it and the thread ruined it will be another can of worms. I guess I will stick to spannering it on and off when needed. I'm disappointed, how have they designed it to be so clever and worst of all why does it take 2-3 days of driving before it register anything...
I don't even want to get the spacer now. I guess if I find a bolt that size or a spark plug, I could give it a try just to confirm and eventually report back.

[jakermac]

Yup. Spark plug will plug the hole perfectly. 18mm threads.

[r0nd3L]

There are plugs that do specifically this, just search for oxygen sensor plug.

[jakermac]

There are for sure. But sometimes it's easier to find a spark plug, depending on the locale.

[Cobra1956]

Do more research. Your o2 sensors should just read different. If I recall the system works like this: MAF to first o2 determines air fuel mix. First O2 to second o2 determines if cat is working. As long as there is a different reading you should be good.