Does the car have a phone or Voice control?
Do you have any Tele-aid faults showing?
Find the fuse chart in with the tools and pull out these
fuses. 18, 61, 63, 64, and 66.
Let the car sit for 20 min and put fuses back.
Hopefully the ring will reset and comeback.
If not, there is a hard fault with a D2B component.
We have a special tool at the dealer called the Berger Tester
that can be substituted for a suspect item.
It is basicly a D2B repeater.
Good Luck.
DR.D

__________________
Dr.Diesel -
Shop Foreman
Master Guild Mercedes-Benz Technician.

Think the dealer is expensive? Do you know how much it costs to train a dealer tech? Or buy the required MB special tools to have on hand?