Mercedes-Benz R-Class Owner's Manual page 216

i
Large buildings, bridges, power lines or
large transmitting masts as well as metallic
objects in or on the vehicle may interfere
with the compass display.
Setting the compass*
You will only see this function if Audio 20 is
installed in your vehicle.
Use the following zone map to determine
X
your geographical location.
Controls
Features
Z
213