Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
The audio gateways are known for causing these messages. This was the first year for the Audio Gateways and there were many problems. It is the amplifier and main controller unit all in one. Its located in the left side of the trunk panel, kind of buried behind some sheet metal. You can order a new one from a dealership (recommended) or from ebay. I'll attach some instructions on how to replace it.
Here is the document of the Audio Gateway replacement instructions.