The audio system will fade out after about 45 minutes of driving. It will fade until no sound can be heard regardless of source. The only way to get it to come back is to reset the system or shut off the car. I am not sure what is the root cause but it seems to be related to when the heat is running. Also the problem was first discovered in winter time and did not have the issue on long trips last year in the summer. It is extremely annoying for long road trips.