View Full Version : oxygen sensors quick question. 1 code, but should i replace both pre cat O2's?

Kronic Budz
05-15-2012, 01:54 PM
I have a 1997 2.8 a4. It has 167k miles, iv taken very good care of the car but the check engine light finally came on. It was the code refering to a bad 02 sensor infront of the driver side cat. Boshe sensor costs $120, but is it worth just replacing both? My buddy says no, but i think it would only help my car considering it would only improve gas mileage and the health of the car.

What would you do? I have invested a good amount of money into the car and will plan on keeping it for a while. Oppinions?

thanks for the heads up


05-15-2012, 03:09 PM
if it works it works keep the old one.. its not hard to replace a sensor so when and if the other one goes then replace it then

05-15-2012, 03:32 PM
What Schaefer said, it's a complete waste of money to replace both, if the downstream is still working you'll be wasting money, who's to say the 2nd sensor will ever go

05-15-2012, 04:47 PM
I would replace both at the same time. I'm surprised the secondary O2 sensor hasn't shit the bed yet.