Hi Folks,
Trying to replace both B1 S1&S2 sensors on a C5 4.2L and managed to get the first sensor out (drivers side) but can't seam to get the plug out. Is the a specific technique to pulling these out? Don't want to use any brute force. See attached picture.

Also, another question while I have our attention
The fault codes state there are issues on O2 sensors B1 S1 and B1 S2. I don't have a manual and I ordered them from Amazon and both came with a plug that had 3 wires together and one separate. Do these sound like the right plugs? I was reading another post and one had a plug with 4 wires together and one separate.

 

Pull the black plastic piece away from the firewall. There is a "U" that it clips into. After that, you can use your finger or a small flat head to depress the pin that is locking both ends together. You'll have a better idea of what I'm talking about after you pull it out of the "U".

If I recall correctly, I believe the O2 sensors should have four wires.