I changed the Bank 1 Sensor 1 O2 Sensor a little over a year ago and yesterday for the same error code after checking with the Scanner when check engine light went on.

Its a 2000 Lexus LX470 with 116,000 miles on it.

Any suggestions? Change the sensor again?

 

Change bank 2 sensor 1. Meaning change the other sensor in the front

 

I just bought a '99 LS400 169,000 miles two weeks ago, had to have emissions/inspection as I bought it from a service member with out of state plates (my state/county requires both emissions/inspection). Passed fine two weeks ago, but yesterday I got the same code. Question is why change his other sensor, when the code on my scanner (and presumably his) clearly states 02 Sensor Heater Circuit Bank 1? I would just ask for more information. Should I replace them both at the same time? I really like the car, I have two more years until next emissions, so unless it acts up, or my gas mileage deteriorates, I'm not in a big hurry. Thanks, ahk.

Edit: His was the other side, but again, why change the other one?

 

For some strange reason once one 02 sensor goes out, the other one goes out soon after. The heating element burns out & once you put a new one in it puts a strain on the old one it eventually will burn out & cause the check engine light to come on