I thought i gonna share it for posterity and i hope it will help some.
It wasn't really my idea, I've found some vague advise now buried under tons of forum threads that it is possible, and not wanting to strip and fight all that stuff that is covering lambda sensor at the top of the engine i gave it a go.
If your hand is slim enough to fit in between exhaust pipe and body you may be able to slide the oxy sensor socket over the sensor and with some 50cm of extensions, UJ adapter and extension bar break it loose and than remove without much hassle.
Here is setup



And here breaker bar, shorter would do but it was best i've found lying around



PS
Should i reset ECU now or it is safe to skip on this part and let it re-learn his things?

Bests
J.

 

Hi,

Thanks for sharing! What car did you work on? Is it an AJ26 or an AJ27 engine?
I'm asking because I might face the replacement of an upper O2 sensor in a few weeks. And since it is the sensor on the driver's side I'm not very keen on removing and disassembling all this stuff above it.

I didn't reset the ECU when I did my O2 sensors on the passenger's side. Worked fine. I can't remember having seen any advice on doing so either.

Cheers, Alexander

 

I tried that route, but mine were in there a bit tight, so I wound up doing this, I did upper and lowers, both sides..... https://www.jaguarforums.com/forum/x...cement-195018/

 

I'm unsure for that model of car but generally it's such a vital sensor the PCM will relearn very quickly. Let it idle for a few mins and do some coast downs (from about 50mph allow car to slow a lot without actual braking) if you can, just to help it - unlikely to be required but if you have the right stretch of road (be safe) then worth a go.

 

It is AJ26 engine with only upstream sensors.yes it is tight there but it is tight also on the top of engine. in any case slim hands are a must.
Finally i did hard reset ECU for peace of mind, gonna need few more drive cycles to get it re-learned, my trims looks quite better now but i didn't have a time to test it properly yet.
Highhorse, oh God, you pulled your converters out, +++ for the willpower ..and the tutorial