I do mean the Head Unit and no, there are no other add on modudules to test, just the XM Tuner. The XM Tuner (GEX-P920XM) has been replaced. I am trying now not to use the XM module to see if it still crashes. If it was the IP BUS, would it matter if the XM Tuner was still plugged in? It hasn't ever happend if I select another source. It happens multiple times per commute with the XM tuner selected. They have had the unit apart multiple times, so I would hope that they have looked at the pins at least once. I am not the radio install expert, thus the reason I paid to have mine professio