OBD non communication

Went for Wisconsin emissions today with my 2005 Chevrolet Avalanche The inspection sights main OBD computer gave a Non-Communication code. Tried 3 different lanes at the sight, and still no communication with my Chevrolet Avalanche. Went home and plugged in my Actron OBDII tester. Worked great, PASS, No codes found! Went to Autozone and them put thier scanner on, Passed, No codes found. Went back to testing sight, they were having problems with thier mainframe computer. They reset thier system, and still no communication with my Chevrolet Avalanche . The manager said it was due to me having an "aftermarket electronic item" installed, an electric trailer brake for my travel trailer. I think not. My truck runs great, no codes, no misfires, no blue smoke. What a joke. Anyone have any ideas?
Gus...

Help me out, what is an "Avy?" Is that supposed to be short for Aviator, or Avalanche? Remember, you're on a general forum here, not a vehicle-specific one.

Does your Actron scan tool give you information as to what protocol it is using to communicate with the system? Maybe the inspection station's machine is not compatible with the OBD-II protocol used by your vehicle. Maybe next time you go back you need to take your Actron with you to show them it does in fact communicate. Also, any chance you know someone with the same model year and engine to confirm or reject that it's a protocol issue?

-Rod

Try another inspection station, I had one that would always tear my windsheld wiper.

Hey, Rod,
thanks for the help. I forgot about the general forum. Avy is Chevrolet Avalanche.
I took the vehicle to a different testing station in the City of Milwaukee and it passed, no codes found. I still think the first testing station main frame computer was on the fritz. A guy with a Ford F-150 had the same problem. The testing station manager would have nothing to do with my "testing equipment".
Thanks..
Gus

Glad you got it squared away. Hopefully you didn't need to pay for the first inspection.

-Rod