Page 374 of 481
373 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
#There is a malfunction in the electronic
system.Have the system checked at an autho-
rized Mercedes-Benz Center as soon
as possible.
#Battery/Alternator
Stop VehicleThe battery is malfunctioning.
Considerably greater brake pedal force is
required and the stopping distance is in-
creased.Stop the vehicle as soon as it is safe
to do so. Adjust driving to be consis-
tent with reduced braking responsive-
ness.
Call Roadside Assistance.
Notify an authorized Mercedes-Benz
Center.
#Low Voltage
Start EngineThe battery has insufficient voltage.Start the engine (page 51).
2Brake WearThe brake pads have reached their wear
limit.Have the brake pads replaced as soon
as possible.
!Brake pad thickness must be visually in-
spected by a qualified technician at the intervals
specified in the Maintenance Booklet.
Page 377 of 481

376 Practical hints
What to do if …
During severe operation conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbolDisplay messagePossible cause/consequencePossible solution
DCoolant
Stop Vehicle,
turn engine off.The coolant is too hot.Stop the vehicle in a safe location or as soon
as it is safe to do so and immediately turn
off the engine.
Only start the engine again after the mes-
sage disappears. You could otherwise dam-
age the engine.
Apply the parking brake (page 53).
Observe the coolant temperature indicator
in the instrument cluster (
page 26).
If the temperature rises again:
Contact an authorized Mercedes-Benz
Center immediately.
Warning!G
Driving when your engine is badly overheat-
ed can cause some fluids which may have
leaked into the engine compartment to
catch fire. You could be seriously burned.
Steam from an overheated engine can cause
serious burns and can occur just by opening
the engine hood. Stay away from the engine
if you see or hear steam coming from it.
Stop the vehicle in a safe location away from
other traffic. Turn off the engine, get out of
the vehicle and do not stand near the vehicle
until the engine has cooled down.
!The engine should not be operated with the
coolant temperature above 248°F (120°C).
Doing so may cause serious damage which is not
covered by the Mercedes-Benz Limited
Warranty.
Page 382 of 481

381 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
FPlease don’t
forget your key.This display appears (for a maximum of
60 seconds) if the driver’s door is opened
with the engine turned off and no
SmartKey in the starter switch.
This message is only a reminder.Take the SmartKey or SmartKey with
KEYLESS-GO* with you when leaving
the vehicle.
Change
Key BatteriesThe SmartKey with KEYLESS-GO* batter-
ies are discharged.Replace the batteries (page 402).
Key
Not DetectedThe SmartKey with KEYLESS-GO* is not
recognized while the engine is running
because
the SmartKey with KEYLESS-GO* is
not in the vehicle
there is strong radio-frequency inter-
ference
Stop the vehicle as soon as it is safe to
do so.
Search for the SmartKey.
Otherwise the vehicle cannot be cen-
trally locked nor can the engine be
started again after the engine is
stopped.
Key
Not DetectedThe SmartKey with KEYLESS-GO* is mo-
mentarily not recognized.Change the position of the SmartKey in
the vehicle.
Operate the vehicle with the SmartKey
in the starter switch if necessary.
Page 399 of 481
398 Practical hints
Unlocking/locking in an emergency
Unlocking the vehicle
If you cannot unlock the vehicle with the
SmartKey or KEYLESS-GO*, unlock the
driver’s door and the trunk using the me-
chanical key. Removing the mechanical key
1Mechanical key locking tab
2Mechanical key
Move locking tab1 in direction of ar-
row.
Slide mechanical key2 out of the
housing.Unlocking the driver’s door
Insert mechanical key2 into the driv-
er’s door lock until it stops.
Turn mechanical key2 counterclock-
wise to position1 until the locking
knob moves up.
The driver’s door is unlocked.
Pull the door handle to open the driv-
er’s door.
iUnlocking your vehicle with the mechanical
key and opening the driver’s door or the trunk
will trigger the anti-theft alarm system.
To cancel the alarm, insert the SmartKey or
SmartKey with KEYLESS-GO* in the starter
switch.
1Unlocking
2Mechanical key
Page 418 of 481

417 Practical hints
Flat tire
1Flap
2Air pump switch
3Electrical plug
4Air hose with pressure gauge and vent
screw
5Union nut
Open flap1 on the air pump.
Pull out electrical plug3 and air hose
with pressure gauge4.
Make sure the vent screw on air
hose4 is closed.
Remove the valve cap from the tire
valve.
Screw union nut5 onto the tire valve.
Insert electrical plug3 into vehicle
cigarette lighter socket (
page 249).
Turn the SmartKey in the starter switch
to position1.
or
Press the KEYLESS-GO* start/stop
button on the gear selector lever once
without depressing the brake pedal.
Press I on electric air pump switch2.
The electric air pump should now
switch on and inflate the tire.
Inflate the tire to approximately 51 psi
(3.5 bar).
This takes about 5 minutes for the col-
lapsible tire. Air hose4 and union
nut5 can become hot during infla-
tion. Exercise proper caution to avoid
burning yourself when using the equip-
ment.
Press 0 on electric air pump switch2.
Turn the SmartKey in the starter switch
to position0.
or
Press KEYLESS-GO* start/stop button
on the gear selector lever twice without
depressing the brake pedal.
The electric air pump should now be
switched off.
If the tire inflation pressure is above
51 psi (3.5 bar), release excess tire in-
flation pressure using the vent screw.
!Do not operate the air pump longer than
8 minutes without interruption. Otherwise it may
overheat.
You may operate the air pump again after it has
cooled off.
Page 422 of 481

421 Practical hints
Battery
Disconnecting the battery
Depress parking brake firmly or move
gear selector lever to positionP.
Turn off all electrical consumers.
Remove SmartKey from starter switch.
Vehicles with KEYLESS-GO*:
Press the start/stop button until
the engine shuts off.
Open the driver’s door.
Open the trunk.
Read and observe safety instructions
and precautions (
page 420).
Remove the luggage box (page 397).
Disconnect battery negative lead2.
Remove cover1 from the positive ter-
minal.
Disconnect the battery positive lead.
Removing the battery
Remove the screw-nuts securing the
battery.
Remove the battery bracket.
Pull out the battery ventilation tube
from the battery (depending on battery
arrangement in your vehicle model, the
battery ventilation tube is located on
the left or right side of the battery).
Take out the battery.
!As with any other battery, disconnect the
battery if you do not intend to operate your vehi-
cle for an extended period of time to prevent bat-
tery discharge or connect an accessory battery
charge unit expressly approved by
Mercedes-Benz for your vehicle model to main-
tain the battery charge. Contact an authorized
Mercedes-Benz Center for further information.
The battery, the battery ventilation hose and the
lateral plug must always be securely installed
when the vehicle is in operation.
!Never loosen or detach battery terminal
clamps while the engine is running or the
SmartKey is in the starter switch. Otherwise the
alternator and other electronic components
could be severely damaged.
Have the battery checked regularly by an autho-
rized Mercedes-Benz Center.
Refer to Maintenance Booklet for maintenance
intervals or contact your authorized
Mercedes-Benz Center for further information.
Warning!G
With a disconnected battery
you will no longer be able to turn the
SmartKey in the starter switch and
pressing the KEYLESS-GO* start/stop
button on the gear selector lever will
have no effect
the gear selector lever will remain
locked in positionP
Page 427 of 481

426 Practical hints
Towing the vehicle
Installing towing eye bolt
Front of vehicle
1Cover on right side of front bumper
To remove cover:
Press mark on cover1 in direction of
arrow.
Lift cover off to reveal the threaded
hole for towing eye bolt.
!Towing of the vehicle should only be done
using the properly installed towing eye bolt. Nev-
er attach tow cable, tow rope or tow rod to the
vehicle chassis, frame or suspension parts.
iWhen towing the vehicle with all wheels on
the ground, please note the following:
With the automatic central locking activated and
the SmartKey in starter switch position2, or
KEYLESS-GO
* start/stop button in position2,
the vehicle doors lock if the left front wheel as
well as the right rear wheel are turning at vehicle
speeds of approximately 9 mph (15 km/h) or
more.
To prevent the vehicle door locks from locking,
deactivate the automatic central locking
(
page 116).
iTo signal turns while being towed with the
hazard warning flasher in use, turn SmartKey in
starter switch to position2 and activate the
combination switch for the left or right turn
signal in the usual manner – only the selected
turn signal will operate.
Upon canceling the turn signal, the hazard warn-
ing flasher will operate again.
iThe selector lever will remain locked in park
positionP and the SmartKey will not turn in the
starter switch if the battery is disconnected or
discharged. For more information see “Battery”
(
page 420) or “Jump starting” (page 423).
For information on manual unlocking of the gear
selector lever, see (
page 400).
Page 429 of 481

428 Practical hints
Fuses
The electrical fuses in your vehicle serve to
switch off malfunctioning power circuits.
If a fuse is blown, the components and sys-
tems secured by that fuse will stop operat-
ing.If a newly inserted fuse blows again, have
the cause determined and rectified by an
authorized Mercedes-Benz Center.
A fuse chart is located in the fuse box in
the passenger compartment. The fuse
chart explains the fuse allocation and fuse
amperages.
The electrical fuses are located in different
fuse boxes:
Fuse box in passenger compartment
(
page 429)
Fuse box in trunk (page 429)Before replacing fuses:
Apply the parking brake (page 59).
Make sure the gear selector lever is set
to positionP (
page 169).
Turn off all electrical consumers.
Turn off the engine (page 60).
Remove the SmartKey from the starter
switch.
Vehicles with KEYLESS-GO*:
Open the driver’s door.
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 ap-
proved 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 appro-
priate 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 As-
sistance or an authorized Mercedes-Benz Cen-
ter.