I have a question ,I have a smog test coming up for my 01 HD2500 6.0 L.I know I need to replaceBoth 02 sensers.My question is can they be cleaned to work again or do I need to replace with new.I just priced them and they will be about 80 bucks each if I do the labor.thanks,Joe

 

I doubt it...they'll probably still set codes if cleaned

 

Yeah, replace only. Look around for the cheapest price. Sometimes you'll find them cheaper online then your local parts shop.