Re: HELP getting error message from odb port. Can't get email S test done
Another possible guess is interference by any added electronics. There is a history of tagged on equipment stopping ODBII port communication even though the ECM aka ECU and other modules are able to communicate enough to operate.
My ODBII port was flaky as a result of bad contacts in the fuse box under the steering column. You may want to clean the contacts (there are a lot of them). I couldn't get my DAD unit to work with it. I swapped out the Fuse Box with a new one, finding corrosion on the contacts of the one I removed. I used spray contact cleaner on all the connectors that plugged into the new Fuse Box.