I have gotten the old oxygen sensor out..Have the replacement but can not get to the harness to disconnect. I am not sure if there is a lever to push or some other access besides being underneath the car...any ideas...I can touch the harness but can not get to the back to pull it apart.

 

oh by the way it is an 2002 disco 2!

 

There is a clip on the side you need to press but the problem is that after years of heat and whatnot they pretty much get fused together somewhat you may need to use a screw driver and "carefully" pry the clip open. That was the most frustrating part of doing the O2 sensors IMO.

 

Try hitting it with a bit of silicone spray. It will help it slide out. The plastic does get stiffer as it ages, so have fun!

 

i don't know if the d2 is the same as the d1 but the plug is held to the back of the cylinder head by a metal "hook" you should be able to snap it out of it so you can at least pull the connector to wher you can see it.

 

Once it heats up a little here in the midwest I am going to hit it with some silicone spray....The main problem I am having is getting my hand back to the harness...from the looks of the new harneess the part that is going to remain is very small....Worst case scenario I could just cut and splice the wires???

 

Where the rear o2 sensors are it is just tight but once you get them of the metal tab they are stuck on you can reach them a bit better and then you can work them off.