O2 sensor problem

My XJ is throwing a O2 sensor code. It has Califonia emissions on it...upon inspection the one sensor after the first set of cats (right off the header) was well missing sorta. I bought an O2 sensor for it but the plugs dont match up. They are both round but the one on the sensor has raised "slots" and they dont line up with the other plugh on the harness. Any suggestions? I dont understand how this could happen. I double checked the part number as well.

You might need to cut and splice on the connector from the old sensor. Are the wire colors the same as the old one?

Thats the problem...the sensor that was in there did not have a connector on it. I just took these pics with my phone...maybe it will help. I doubt it though because they all look so similar.

I'm not sure why your O2 sensor harness is all the way over by the shift linkage on the transmission, it should be down on the passenger side by the rear o2 sensor or up by the manifolds. All the sensors have connectors, you probably just haven't found it yet. Unless some previous owner of the jeep hacked it up and did a bad job installing the previous sensor, that is...

Well this thing has 4 o2 sensors. It has cali emissions...2 cats on the manifold and a sensor in front and behind each cat.