2002 S40 "lean bank 1"
 

im getting trouble code showing lean bank 1 a friend says this means the ox sensor is failing but my car has 2 ? my second question is a code idle higher than expected about a year ago i had the idle control valve replaced pluse other things to the tune of 1700+ dollars and im sure i got ripped off cause within a week code came back please help !!

The 2nd O2 sensor is to check that the cat converter is working correctly.

Your problems may be related. A vacuum leak will cause a high idle and will make the car run lean. Do you hear a hissing sound at idle?

Do you have other symptoms like extended cranking before the engine starts?

thanks for the info , i havent noticed any hissing but ill start checking vac lines , and engine starts perfectly no extended cranking

Good. The extended cranking is a bad fuel pressure regulator so I was trying to rule that out as a bad regulator could cause the engine to run lean also.

I recently replaced my lower O2 sensor as well. I bought the "exact fit" Bosch from Advance Auto Parts so I wouldn't have to splice the generic one into my existing harness. If money is tight the generic works just fine though. Replacement was fairly easily as long as you have the correct wrench. I couldn't get the special O2 socket to fit so I used a 3/4" wrench from under the car.

02 sensor
 

Sorry for added to an old post. I have the same code bank 1 lean, should i replace the front or rear sensor with this code?

See my post in your own thread.