The check engine light on my Cooper S with 87000mi has started coming up periodicly. It seems to appear and disappear randomly. This last time, it seems to want to stay on so I got my code reader and it returned 2 codes.

P0138 and P2096.

Both of these seem to be in the same area. Any thoughts on how I should proceed?

Order a pair of O2 sensors. got the post cat i2 removed and installed a new one. When I started the mini up I now have 4 codes. none matched any of the codes I have before. I can clear them but the come back .. All I did was change the oil and remove the post cat i2 sensor. Hope to try and do the pre cat today.

I am not sure I understand why changing the post cat would have caused these error codes to appear

p0037
p0340
p0031
p0445

I've been dealing with this for the last couple of months. Check engine light will stay on of a few days and then go off for a few days. Mechanic thinks it's a hairline crack in exhaust manifold, but didn't have the equipment to test. My light just came on again and when I googled p1038 and P2096, this thread came up. What did yours turn out to be? Sorry to hear about your other codes.

I replaced the post cat O2 sensor and all of the codes except for P0130 went away. Since my Coop still has the original O2 sensors, I am going to try and replace the Pre Cat O2 Sensor (needed to be done regardless). I am not sure how I am going to get my wrench in there to get it out. I had to use a 5lb sledge to get the post cat sensor moving. I couldn't use an O2 sensor socket. Had to use a sawsall to cut the top of the O2 Sensor off so I could get a 22mm socket on it.