Have taken this from another forum but I think the member is on here as well. Although for a W211, same may apply? Give it a go and see what happens.
211 E class As of 1/9/03 and all W219 CLS Class
a) Turn ignition key to '1'
b) Press the lower system selection button (left hand edge of steering wheel) until you have the Basic display with mileage or temperature in the display
c) Press the odometer reset button briefly 3 times and you see the voltage display on the cluster and a ping is heard
d) use the scroll down arrow button until you see the 'Service menu'
e) Use +/- buttons to select the menu item "Confirmation" then press the lower system selection button to confirm ("Complete service" is highlighted in display)
f) Confirm full service by pressing lower system selection button ("Service Confirmed" appears)
g) Press top system selection button until you get back to Service menu
h) Use +/- buttons to select the 'Special Work' menu and Press the lower system selection button to confirm
i) Use +/- buttons to select Service 13 & press lower system selection button to confirm
j) Use +/- buttons to select the oil grade you used & press lower system selection button to confirm (nb, where only 1 grade of oil is allowed, there wont be a selection available)
k) repeatedly press bottom system selection button until out of service mode
