Page 375 of 474
374 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
•Coolant
Stop, turn engine 
off
.
The coolant is too hot.
Among other possible causes, 
the poly-V-belt could be broken.Stop the vehicle in a safe location or as soon as it is 
safe to do so.
Turn off the engine.
Apply the parking brake (page 59).
Check the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise, the engine will 
overheat due to an inoperative water pump which 
may result in damage to the engine. Contact an 
authorized Mercedes-Benz Center.
If it is intact:
Wait for the message to disappear before restarting 
the engine.
Doing otherwise could result in serious engine 
damage that is not covered by the Mercedes-Benz 
Limited Warranty.
(Continued on next page) 
     
        
        Page 381 of 474

380 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
KRetractable Roof Operation
Please WaitThe on-board voltage is too low.Start the engine.
The hardtop drive system was 
shut down for safety reasons after 
multiple, consecutive attempts to 
raise or lower the hardtop.After about 10 minutes you can open or 
close the retractable hardtop.
Switch on the ignition (page 37).
Repeat the opening or closing 
procedure.
Retractable Roof
LoweringThe retractable hardtop is not 
completely opened or closed. The 
roof hydraulics will start to lose 
pressure.Make sure the retractable hardtop is 
completely opened or closed 
(
page 240).
Retractable Roof
Operation Only At StandstillYou have attempted to open the 
retractable hardtop while driving.Stop the vehicle in a safe location and try 
to open the hardtop again.
Retractable Roof Not
Opened/Closed CompletelyYou are driving with the retract-
able hardtop not properly locked.Stop the vehicle in a safe location. Ob-
serve the traffic situation around you.
Push the retractable hardtop switch for-
ward or rearward until the retractable 
hardtop is completely closed or open 
(
page 240). 
     
        
        Page 382 of 474
381 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
IPlease
get a new key.The SmartKey is malfunctioning.Contact an authorized Mercedes-Benz 
Center.
Remove KeyYou have forgotten to remove the 
SmartKey from the starter switch.Remove the SmartKey from the starter 
switch.
.3rd Brake LampThe high mounted brake lamp is 
malfunctioning. This message will 
only appear if a critical number of 
LEDs have stopped working.Contact an authorized Mercedes-Benz 
Center as soon as possible.
AUTO-Light
InoperativeThe light sensor is malfunctioning. 
The headlamps switch on automati-
cally.Contact an authorized Mercedes-Benz 
Center as soon as possible.
To switch off the headlamps (U.S. vehicles only):
In the control system, set lamp operation to 
manual mode (
page 143).
Switch off headlamps using the exterior 
lamp switch (
page 109). 
     
        
        Page 386 of 474

385 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
.Marker Lamp
Rear RightThe right rear side marker lamp is 
malfunctioning. This message will 
only appear if a critical number of 
LEDs have stopped working.Contact an authorized Mercedes-Benz 
Center as soon as possible.
Tail Lamp, Left
Auxiliary Bulb OnThe left tail lamp is malfunctioning. 
This message will only appear if a 
critical number of LEDs have 
stopped working. A backup bulb 
has been brought into use.Contact an authorized Mercedes-Benz 
Center as soon as possible.
Tail Lamp, Right
Auxiliary Bulb OnThe right tail lamp is malfunction-
ing. This message will only appear if 
a critical number of LEDs have 
stopped working. A backup bulb 
has been brought into use.Contact an authorized Mercedes-Benz 
Center as soon as possible.
Switch Off
LightsYou have removed the SmartKey 
from the starter switch, opened the 
driver’s door and left the headlamps 
on.Switch off the headlamps (page 61).
Switch off lights or
remove key
.
The exterior lamp switch is set to 
positionU, and you have forgot-
ten to remove the SmartKey from 
the starter switch. The parking 
lamps remain switched on.Switch off the headlamps (page 61).
or
Remove the SmartKey from the starter 
switch. 
     
        
        Page 395 of 474
394 Practical hints
Unlocking/locking in an emergency
Unlocking the vehicle
If you cannot unlock the vehicle with the 
SmartKey, open the driver’s door and the 
trunk using the mechanical key. Removing the mechanical key
1Mechanical key locking tab
2Mechanical key
Move locking tab1 in direction of 
arrow.
Slide mechanical key2 out of the 
housing.Unlocking the driver’s door
Insert mechanical key 2 into the 
driver’s door lock until it stops.
Turn mechanical key 2 counterclock-
wise to position1 until the locking 
knob moves up.
The driver’s door is unlocked.
Pull the door handle to open the 
driver’s door.
iUnlocking the vehicle with the mechanical 
key and opening the driver’s door or the trunk 
will trigger the anti-theft alarm system 
(
page 90).
To cancel the alarm, insert the SmartKey in the 
starter switch.
1Unlocking
2Mechanical key 
     
        
        Page 420 of 474

419 Practical hints
Flat tire
PressI on electric air pump switch2.
The electric air pump switches on and 
inflates the collapsible tire.
Inflate the collapsible tire to approxi-
mately 51 psi (3.5 bar).
This takes about 5 minutes. Air 
hose4 and union nut5 can become 
hot during inflation. Exercise proper 
caution to avoid burning yourself when 
using the equipment.
Press0 on electric air pump switch2.
Turn the SmartKey in the starter switch 
to position0.
The electric air pump is switched off.
If the tire inflation pressure is above 
51 psi (3.5 bar), release excess tire 
inflation pressure using the vent screw 
on air hose4.
Detach the electric air pump.
Reinstall tire valve cap.
Store electrical plug3 and air 
hose4 behind flap 1 and place the 
electric air pump back in the trunk.
Lower the vehicle (page 420).
!Compare the recommended tire inflation 
pressure for your vehicle with the tire inflation 
pressure on the yellow label located on the spare 
wheel rim.
If the tire inflation pressure on the yellow label 
on the spare wheel rim differs from the values 
given in this Operator’s Manual, inflate the 
collapsible tire to the recommended tire inflation 
pressure given on the yellow label on the spare 
wheel rim.
!Do not operate the electric air pump longer 
than 6 minutes without interruption. Otherwise it 
may overheat.
You may operate the electric air pump again 
after it has cooled off.Warning!G
Follow recommended tire inflation 
pressures.
Do not underinflate tires. Underinflated tires 
wear excessively and/or unevenly, 
adversely affect handling and fuel economy, 
and are more likely to fail from being over-
heated.
Do not overinflate tires. Overinflated tires 
can adversely affect handling and ride 
comfort, wear unevenly, increase stopping 
distance, and result in sudden deflation 
(blowout) because they are more likely to 
become punctured or damaged by road 
debris, potholes etc. 
     
        
        Page 433 of 474

432 Practical hints
Fuses
The electrical fuses in your vehicle serve to 
switch off malfunctioning power circuits.
If a fuse is blown, the components and 
systems secured by that fuse will stop 
operating.If a newly inserted fuse blows again, have 
the cause determined and rectified by an 
authorized Mercedes-Benz Center.
A fuse chart explains the fuse allocation 
and fuse amperages. It is located in the 
fuse box in the passenger compartment 
(
page 433).
The electrical fuses are located in different 
fuse boxes:
in the passenger compartment on the 
driver’s side (
page 433)
on the driver’s side of the engine 
compartment (
page 433)Before replacing fuses:
Apply the parking brake (page 59).
Make sure the gear selector lever* is 
set to positionP (
page 157) (manual 
transmission to Neutral).
Turn off all electrical consumers.
Turn off the engine (page 61).
Remove the SmartKey from the starter 
switch.
Warning!G
Only use fuses approved by Mercedes-Benz 
with the specified amperage for the system 
in question and do not attempt to repair or 
bridge a blown fuse. Using other than 
approved fuses or using repaired or bridged 
fuses may cause an overload leading to a 
fire, and/or cause damage to electrical 
components and/or systems. Have the 
cause determined and remedied by an 
authorized Mercedes-Benz Center.
iA blown fuse must be replaced by an 
appropriate spare fuse (recognizable by its color 
or the fuse rating given on the fuse) of the 
amperage recommended in the fuse chart. 
Any Mercedes-Benz Center will be glad to advise 
you on this subject.
iIn case of a blown fuse contact Roadside 
Assistance or an authorized Mercedes-Benz 
Center.