what repairs are required for O2 censor
Why do you think it needs repair?
Did the check engine light come on, did you get it read, if so what was it?
Is it running ok?
We need more info
Just because the Check Engine light is on, does not automatically mean that the oxygen sensor is at fault. There’s a whole load of other things that can make it turn on, so the first thing to do is get the codes read. Autozone will do this for free, so get them read and post back here.
Before the OBDI and OBDII Power Control Modules, there were some cars that had a reminder to service the emisssion system. This light came on after a set number of miles. The service involved looking at the various emissions systems and replacing the O2 sensor which was usually lazy by then. This is no longer the case. As budd mentioned have the PCM scanned for fault codes; post those back; and we can go from there.
Hope that helps.