Before I begin I will say that I did research previous threads however I feel my situation may be a little different.

About 2 months ago I got the CEL and took it to Autozone, got code p2098, bank 2 02 sensor I believe. During this time I figured I would use up the tank then get new gas and check later on. Anyways the CEL went away randomly for a day or two, then came back. A few days later I had battery problems (it was pretty cold for a few days) so had to get a jumpstart.

Anyways I checked today to make sure the p2098 was the reason of the CEL but now it appears to be a p0400, the which is a problem with the EGR from what I've seen. So I realize these are slightly correlated, would fixing the EGR resolve the problem or is the underlying issue still the 02 sensor?

I should clarify I had an exhaust shop check from cracks and a leak, which they confirmed there was not - contradicting what the dealership told me (they wanted to replace both cats and 02 sensors (the car only had 2 o2 sensors according to them for $5k)

Any help is greatly appreciated!!!