correct. In saying that, I hoisted up my car earlier today and we found out there was 2 extension harness plugged in, so 4 all up. We unplugged 1 extension on each side to clean it up. The current ones are heat shielded.

Bank 2 or the right hand side had a broken clip, so nothing was locking it together. We suspect that could be the culprit to the P2241. We de pinned and re pinned it with the clip from the extra extension harness that we removed, and now we've got P0051. So what does this mean? nfi. i am not sure if its harness is cooked or the o2 sensor is cooked now.

EDIT: turns out the one of the wires for the extension harness was not crimped in and got loose over time.

From what i have read, removing the extension harness is more of a hassle. Any form of heat shield is good, as long as its not touching the down pipe!

 

Forgot to update this after my fix. Pinged Rafi from RR and he recommended going ahead and getting the harness from PPE along with the sensor. Replaced both and no issues since.

 

BOLD is mine for emphasis. This is why Lexus puts so much effort into their wiring harnesses. They're still not perfect, but they're really the target for any OEM. Very few aftermarket harnesses are built to the same standard as Toyota/Lexus, and many are really just very poorly constructed. I've had brake wear devices for the wife's GS F from aftermarket sources, and I won't run them. The pins are junk, the crimps are junk, even the wire is sketch. I am very confident the inherent reliability of Toyota's automobiles is directly related to the fanatic attention to detail in their wiring. It's truly rare to have a wiring problem from the factory, and the wiring problem in my Supra only showed up when it was 15 years old and I'd done probably 20 ECM swaps with it over time.

 

P2241 popped up couple weeks ago, thank you everyone who chimed in to this thread.
I went under the car to inspect, while my upstream sensors were replaced not too long ago, I was suspicious of the extension. I unplugged the connector that goes to the sensor, as the other one is pretty impossible to access with the thick Sikky V2 headers and an extra suspension brace.
Well, upon unplugging, bunch of sand crap came out of the connector, so I have blown some air through it used some electrical spray cleaner. I checked the live data stream, everything looked spot on and even for both banks. One week later, no cell, even the permanent P2241 is gone, so happy to report, it is all sorted.

So before replacing anything, given no obvious signs of damage, cleaning the bottom connection should be the first thing to try, hope this helps the next guy.