Oxygen Sensors

MY CEL is on Again in my wifes beetle 1.8T, I had the code read a few weeks back and have done everything on the list of things to look at, except replacing the O2 senors and catalyst. Is it best to just replace both O2 sensors at the same time. Or is the front / back one more important then the other.

the front upsream 02 is more important, the one after the converter is usually used just to measure how well the catilitic converter is performing, the front one is responsible for fuel control

thank you, I'll post the results of how it turns out

hey I'am sorry I should have read your post more carefully ,on your list of things to replace it says the catalyst, if the catalyst is bad it may have a code set for the rear 02 sensor and maybe it's just a bad catalyst or just a bad rear sensor .you can have the catalyst tested at an emissions shop, and the fault code usually denots wich sensor is at fault upstream or down stream. hope I haven't steered you wrong.