Lack of audio or cell phone functionality may be related to the failure of the audio gateway module.Google+
Car Problem Reports
Mercedes-Benz E350 4MATIC Failed Gateway Module May Cause Lack of Audio/Cell Phone Functionality
Mercedes-Benz E350 4MATIC Problem
Average Mileage: 51,530 mi (10,123 mi - 120,000 mi)
Battery was going dead after sitting for a few days, I found the negative terminal totally loose (floating around) Ironically, the dealer was the last one to work on it when they replaced the center camshaft. I charged the battery and car worked fine except the radio didn't work- the mercedes logo comes on & then disappears. The dealer says they want $2600 to fix this issue but cannot guaranty I don't have other thing drawing down the battery.
Visitor, 2008 Mercedes-Benz E350 4MATIC, 24,000 mi
Has never worked from day 1, dealer is lost and can not fix it and charges me for inspection every time, claims this is not covered by warranty.
Just a lousy car