2003 Ford Excursion OBD Realtime Sensor Data Not Communicat

Hi,

I recently moved to CA where I need to have my truck smogged. Part of the test consists of a OBD diag and they are telling me there is nothing wrong, but the data from the OBD is not communicating with their computer. He said to drive it 50 or so miles, which I did and still no OBD results. Looking at his computer system, it looks like it cannot read realtime data. I have no problems with the truck, no check engine, no aftermarket accessories and no other problems to speak of. I am going to take it to another shop but at the end of the day, I am confused why the computer is not returning OBD information. Could the computer be bad? Could it be that they have a bad terminal to read my information?