I just had my radio checked out and repaired due to a volume issue. The volume adjusts up or down without touching the unit. The change is just enough to have to adjust back due to being too low or too high or you can just wait for it to adjust back by itself. I was told that the radio is OK and that the radio communicates with the cars computer and the issue may be the speed sensor. On some cars the volume will adjust with speed due to an increase in interior noise. Does anyone know about this with the ML series? Thanks