2000 Lexus Es 300 O-sensor

[greek271]

Ok guys maybe you can help. Here is my problem. My lexus is showing the "code p0171 Bank #1 too lean". I know it is the oxygen sensor, but I don't know which one to replace. Is it the front, back??? How do i figure this out?

Thanks,

Kris

[Martin Tran]

Ok guys maybe you can help. Here is my problem. My lexus is showing the "code p0171 Bank #1 too lean". I know it is the oxygen sensor, but I don't know which one to replace. Is it the front, back??? How do i figure this out?

Thanks,

Kris

My car threw the exact same code, and it was due to a dirty MAF sensor. Clean the MAF with some electrical contact cleaner - I had to clean mine twice. The code hasn't reappeared in 2 months.