Does the connector look damaged or the pins look a bit weird? If you look at the back of the connector there's two tabs that secure it.
Kind of forgot sbout this for a while, is there a "faceplate" for the OBD? I seem to recall you posting it on a different thread and it was quite cheap. I'm thinking of trying to replace that and see if it cures the problem rather thsn have a shop troubleshoot it for me. They were able to get a connection but I can't with the SG so it seems like it might be the issue.