231 Starter switch
Te ch n i c a l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index Important!
If the electronic key is left in the starter switch 
position 0 for a extended period of time, it can no longer 
be  turn ed  in  t he lock . In  t his  cas e, rem ove electron ic  key 
from starter switch and reinsert.
Caution!
To prevent accelerated battery discharge and a possible 
dead battery, always remove the electronic key from the 
starter switch. Do not leave the electronic key in starter 
switch position 0.Notes:
A warning sounds when the driver’s door is opened 
with the electronic key is in starter switch position 1 
or 0.
With the engine at idle speed, the charging rate of the 
alternator (output) is limited.
It is therefore recommended that you turn off 
unnecessary electrical consumers while driving in stop-
and-go traffic. This precaution helps to avoid draining of 
the battery.
Unnecessary strain on the battery and charging system 
may be minimized by turning off the following power 
consumers, for example:
Heated seats, rear window defroster. In addition, the 
automatic climate air volume control should be set to 
the lowest position. 
251 Driving instructions
Te ch n i c a l
data Instruments 
and controlsOperationDrivingInstrument 
cluster displayPractical hints Car care Index If the vehicle is parked af ter being driven on salt treated 
roads, the braking efficiency should be tested as soon as 
possible after driving is resumed while observing the 
safety rules in the previous paragraph.Winter driving
Have your vehicle winterized at your authorized 
Mercedes-Benz Center before the onset of winter.
•Change the engine oil if the engine contains an oil 
which is not approved for winter operation. For 
viscosity (SAE / CCMC class) and filling quantity, 
seepage357.
•Check engine coolant anticorrosion / antifreeze 
concentration.
•Additive for the windshield washer and headlamp 
cleaning system: Add MB Concentrate “S” to a 
premixed windshield washer solvent / antifreeze 
which is formulated for below freezing 
temperatures, see page 302.
•Test battery: Battery capacity drops with decreasing 
ambient temperature. A well charged battery helps 
to ensure that the engine can be started, even at low 
ambient temperatures.
Wa r n i n g !
If the vehicle becomes stuck in snow, make sure 
that snow is kept clear of the exhaust pipe and 
from around the vehicle with engine running. 
Otherwise, deadly carbon monoxide (CO) gases may 
enter vehicle interior resulting in unconsciousness 
and death.To assure sufficient fresh air ventilation, open a 
window slightly on the side of the vehicle not 
facing the wind.