Page 122 of 474

121 Controls in detail
Control system
Control system
The control system is activated as soon as 
the SmartKey in the starter switch is 
turned to position1. The control system 
enables you to
call up information about your vehicle
change vehicle settings
For example, you can use the control 
system to find out when your vehicle is 
next due for service, to set the language 
for messages in the instrument cluster 
display, and much more.
The control system relays information to 
the multifunction display.
Multifunction display
1Main odometer
2Trip odometer
3Current program mode 
(automatic transmission* only)
4Status indicator (outside 
temperature/digital speedometer)
5Current gear selector lever posi-
tion/gear range 
(automatic transmission* only)
iThe displays for the audio systems (radio, 
CD player) will appear in English, regardless of 
the language selected.
Warning!G
A driver’s attention to the road and traffic 
conditions must always be his/her primary 
focus when driving.
For your safety and the safety of others, se-
lecting features through the multifunction 
steering wheel should only be done by the 
driver when traffic and road conditions 
permit it to be done safely.
Bear in mind that at a speed of just 
30 mph (approximately 50 km/h), your 
vehicle is covering a distance of 
44 feet (approximately 14 m) every second. 
     
        
        Page 232 of 474

231 Controls in detail
Audio system
Accepting an incoming call
If the telephone is active in the background 
(reception symbol is visible in the display), 
the audio source is muted when an incom-
ing call is received. A ringing tone can be 
heard and the caller’s telephone number, 
or the name under which the telephone 
number has been saved in the telephone 
book, appears in the display. If the caller’s 
number is not relayed, 
CALL will appear in 
the display.
Press s button.
The call is accepted.Muting a call
It is possible to mute a call; the caller is 
then no longer able to hear you.
Mute on
PressMUT soft key.
MIC MUTE will appear in the display.
Mute off
PressMUT soft key again.
Terminating a call
Press t button.
The current call is terminated and the 
muted audio source becomes active 
again.Accepting a second incoming call
If you receive another call during an 
already active call, you can accept the 
second call and switch between the two.
Accepting a second call
Place new call by entering 
telephone number manually.
You are connected to the second 
caller; the first caller is kept on hold.
iYou will be notified of the second call acous-
tically, but you will not see this in the display. 
     
        
        Page 378 of 474
377 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
±Display Malfunction
Drive To WorkshopCertain electronic systems are un-
able to relay information to the con-
trol system. The following systems 
may have failed:
Coolant temperature display
Tachometer
Cruise control display
Have the electronic systems checked by an 
authorized Mercedes-Benz Center.
NCheck oil level
when next refueling
.
SLK 280 and SLK 350 only:
The engine oil level has dropped to 
a critical level.Check the engine oil level (page 296) and 
add engine oil as required (
page 299).
If you must add engine oil frequently, have 
the engine checked for possible leaks.