850 Wagon, Check engine light?

It is probably coincidental that the muffler and O2 sensor are going bad at about the same time.

John

O.K. thanks the input.

It is certainly possible, especially if the sensor identified is the #2 sensor, the one after the converter. It makes sense to me to have the muffler work done and then see if the O2 sensor codes go away. My hunch is that they will, but that's only a hunch. If the codes point to the #1 sensor, the one before the converter, it is less likely.

Mike

Mike, on the receipt under comments it said something like "error code o2 #2"

I didn't know there were two o2 sensors. It has been a few days and the check engine light has NOT come back on yet... I think I'll follow your advice, have the muffler done before having the sensor done, especially if the check engine light doesn't come on right away. I assume if the sensor was really really bad, then it would come on pretty quickly.

Thanks,

-Atif

Sounds good to me. The front O2 sensor provides the feedback to adjust the mixture, while the rear one just monitors the output of the catalytic converter to see if the whole system is working right - particularly the converter. It doesn't take much air on that one to convince it something is wrong. The second sensors were mandated by the US OBDII standard in 1996, but I imagine other countries required them earlier than that.

Mike