There is a notch at the bottom of the OBD II connector that "lock" in place, if you squeeze on the sides and then pull you should be able to get it off.

If that does not work you can try prying gently with a small screwdriver right around the interface between the cable and the car plug near the notch, you will see the notch if you feel around the bottom of the OBD II connector - it's a bit inconvenient  to see the bottom of the cable  when attached though...

Thanks
Paul

Hi JMJNet,

I've never come across that problem with all the cables I've used, but I heard from a user some time back who had the same type of problem. He said he worked around it with a hair dryer. Heated the cable connector and then slid it on. It then assumed the new size and slipped off relatively easily from then on.

Probably worth giving it try.

Regards
Graham McKechnie
GLM Software
www.glmsoftware.com