Hello everyone! I've been having issues with my car's OBD not communicating with the diagnostic tool and I've been trying to figure out what could be the cause of the issue. My cigarette lighter socket wasn't working either so I figured this must've been an issue with the OBD fuse but I pulled it out and it doesn't seem to have blown. I was considering checking to see if other fuses for the cigarette lighter were blown (specifically fuses 30, 84, 85) later today and while that might fix my cigarette lighter socket, I'm not sure it'll fix the OBD communication error. I was reading somewhere else on this forum that I have to check if I'm grounded and see if B+ is at the DLC but I have no idea what that means at all.

Side note; when replacing fuses, should I disconnect my car from its battery?

Also, this is kind of my first time self-repairing my car so if you choose to offer advice, please put it in layman's terms.

Thank you.