I have been getting this code on and off (when I reset it) over the past year, I decided today to investigate after reading about it probably needing a new sensor as my mileage is almost 100K.

Anyhoo, upon poking around under the car I found the sensor was actually loose, no the nuts did not come loose, they have rotted away! I was able to wiggle the small shield around the sensor off the studs and then just pull the sensor out of the exhaust pipe with no effort at all. No wonder I have been getting a fault code the thing must have been either leaking gas or sucking in air and one of these affected the Nox readings. It needed the threads cleaning and a bit of exhaust sealer (as the old gasket had rotted into dust!) and now seems to be fine, time will tell if it has affected the sensor permanently or not.

Might be worth a squint under your chariot to check out these 13mm nuts......as Lexus seem to use just bog standard mild steel nuts, nothing at all left of them except for a bit of dross stuck in the stud threads which needed cleaning out before new stainless steel nuts were used as replacements.

 

Yup, I had that code as well. My sensor was rusted on, and so were the nuts. After replacing the sensor, the code have never returned.

 

Hyper, my point was that I never had to replace the sensor it was the small air leak that the rusted nuts had caused by degrading the seal between the sensor and the exhaust flange, I merely had to replace the nuts and clean the sealing surfaces.......and so far no more code.

Although I read these forums previous to crawling under the car and in anticipation I had already bought a new sensor, I now have a sensor for sale!