OBD II port not communicating with state (TX) emissions test equipment. all fuses check good. Can OBD II diagnostic tool reads with no problem. during emission test setup tach and temp intermittently go to zero, abs light comes on and stays, MIL lights and then goes out. state equipment never reads any data from car. When unplugged and restarted all systems and readings return to normal. Car has no issues or dtc codes. This has been repeated at two separate testing facilities. Including the facility that tested and certified the car in 2011 - same car same equipment. Any ideas if this is a software failure or a wiring failure?