Ptrigg17

My 2012 E550 Cabrio with 35K flashed the dreaded check light yesterday, went to AutoZone , code P2626 , O2 sensor pumping current trim circuit/open bank 1 sensor 1. I would like to replace the sensor myself but I cannot locate it. I checked from underneath and above , I can see the converter but no sensors. I am considering removing the inner fender liner next. Has anyone attempted this and can help me locate the pre cat sensor on the passenger side of my M278 engine.

Chevota

It should be right under your left foot or toes when in the right seat. I think it's pointing at your foot too, otherwise it would hit the eng mount. I think, itza fuzzy memory....
It's gotta be there before the cat, obviously, so just feel around. A little mirror on a telescoping rod, sold for exactly that, is super helpful for stuff like this, but either way I bet it's much easier to find if you're under the car.
Just be sure an use jack stands b/c I have two near skill crushing stories from not using them! One a jack slipped, the other the jack failed, instantly! :o Don't want that on your head stone

Ptrigg17

Do you think I will be able to see it by removing the inner fender liner, then no risk by getting under the car.

konigstiger

As a matter of reference (not 207, engine removed) replacement part #s:

Ptrigg17

Thank you, will take another look. Just called a local (Sarasota Fl) independent shop, $135 to diagnose and $250-300 to replace the sensor. I can buy the sensor from Parts Geek for around $80 .