In case you forgot my post from a couple weeks ago, my Hyundai Accent
GT failed the smog test in CALIF due to an OBD2 Communication/System
Malfunction Light.

Hyundaitech, here, suggested it could be their equipment not
communicating with my car as opposed to my car having a problem, so I
checked for that on the net, even called the manufacturer of the smog
equipment and both sources said that was not the case. I also called
the testing garage to ask them if it might not be possible their
system was not communicating with my car correctly, and they assured
me that was not the case.

So, I took the car back in to the original testing place to track down
the problem, because I didn't have time to spend a day down where the
nearest Hyundai Dealer is.

Left it with the garage, and about an hour later they called me back
and said, "The problem was with our scanner. We took it to another
testing station and their system was able to read it."

So they refunded my money and I took it to the other tester and it
passed with flying colors.

So Hyundaitech was right after all, and all the experts who told me it
wasn't "their equipment" were wrong. Even the manufacturers of the
smog testing equipment!

The downside of all this is:
1) I had to make several trips back and forth to the garage, some by
bus since I had to leave my car behind with the garage, and I wasted
all that time, and the time on the net and on the phone, before
finding out it was THEIR mistake.
2) The place that could communicate with my car was a Test Only
station so they charged me $60 instead of the $29 I could have got it
done for at just any station. But I couldn't "shop around" because I
had to go with the station that I knew could work with my car, and
didn't have time nor patience to shop around for it.
3)I had to pay a $19 penalty for filing late, due to being jerked
around by the testing station.

The upside is it could have been worse; I could have been cheated by a
dishonest garage who told me I needed some expensive work when all I
needed was to take it to another testing station.

So all in all, I'm just glad to be done with this sh*t and next year I
just have to check with the cheaper testing stations to make SURE they
will communicate with my car's computer.

Thanks to all the people who responded to my original post about what
the problem was, especially Hyundaitech who wins the gold star for
having had the correct answer.