Page 400 of 521

399 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
#
Battery/Alternator
Stop vehicle
The battery is malfunctioning.
The electrohydraulic brake system re-
quires electrical energy and therefore has
only limited operation. Considerably
greater brake pedal force is required and
the stopping distance is increased.
Stop the vehicle in a safe location as
soon as it is safe to do so. Adjust driv-
ing to be consistent with reduced
braking responsiveness.
Notify an authorized Mercedes-Benz
Center.
Low voltage
Start engine
The battery has insufficient voltage.
Start the engine (
page 50).
Malfunction
Electrical consumers
switched off
The consumer battery has insufficient
voltage and can no longer supply the con-
venience functions such as seat ventila-
tion*.
The electrical consumers will come back
online as soon as on-board voltage is suf-
ficient.
(
Backrest, right rear
not locked
The rear seat backrest is not engaged.
Adjust the rear seat backrest until it is
fully engaged in position.
Backrest, left rear
not locked
The rear seat backrest is not engaged.
Adjust the rear seat backrest until it is
fully engaged in position.
Page 401 of 521

400 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause/consequence
Possible solution
2
Brake wear
Visit workshop
The brake pads have reached their wear
limit.
Brake pad thickness must be visually
inspected at the intervals specified in
the Maintenance Booklet.
Have the brake pads replaced as soon
as possible.
T
Reduced braking power
Depress brake
pedal fully
The electrohydraulic brake system is in
emergency operation mode. Consider-
ably greater brake pedal force is required
and the stopping distance is increased.
The maximum speed is limited to 55 mph
(90 km / h).
Do not drive any further.
Stop the vehicle as soon as it is safe
to do so and notify an authorized
Mercedes-Benz Center.
Prevent the vehicle from rolling away
by blocking the wheels with wheel
chocks or other sizable objects.
Call for Roadside Assistance.
(USA only);(Canada only)3
Reduced braking power
Start engine
The battery has insufficient voltage and
cannot supply sufficient power to the
electrohydraulic brake system.
Start the engine (
page 50).
The message disappears when suffi-
cient voltage is available.
!Brake pad thickness must be visually
inspected by a qualified technician at
the intervals specified in the
Maintenance Booklet.
Page 405 of 521

404 Practical hintsWhat 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 symbol
Display messages
Possible cause/consequence
Possible solution
Ï
Coolant
Stop, engine off
The coolant is too hot.
Stop the vehicle in a safe location or
as soon as it is safe to do so.
Only start the engine again after the
message disappears. You could other-
wise damage the engine.
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.
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 411 of 521

410 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause/consequence
Possible solution
Y
Hood open
You are driving with the hood open.
Close the hood (
page 319).
F
Key
Check battery
The SmartKey with KEYLESS-GO* batter-
ies are discharged.
Change the batteries (
page 431).
Key
not recognized
The 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 in a safe location 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 recognized
The 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 nec-
essary.
Key
still in vehicle
A SmartKey with KEYLESS-GO* left in the
vehicle was recognized while locking the
vehicle from the outside.
Take the SmartKey out of the vehicle.
Keyless Go
Check system
The KEYLESS-GO* system is malfunction-
ing.
Visit an authorized Mercedes-Benz
Center as soon as possible.
Page 427 of 521
426 Practical hintsUnlocking/locking in an emergencyUnlocking the vehicle
If you cannot unlock the vehicle with the
SmartKey or SmartKey with
KEYLESS-GO*, 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 ar-
row.
Slide mechanical key2 out of the
housing.Unlocking the driver’s door
1Unlocking
Insert the mechanical key into the
driver’s door lock until it stops.
Turn the mechanical key counterclock-
wise to position1.
The driver’s door is unlocked.
iUnlocking your vehicle with the me-
chanical key will trigger the anti-theft
alarm system. To cancel the alarm, do
one of the following:
Press button Œ or ‹ on the
SmartKey.
Insert the SmartKey in the starter
switch.
Vehicles with KEYLESS-GO*
Pull the outside door handle.
Press the KEYLESS-GO* start/stop
button.
Page 442 of 521

441 Practical hints
Flat tire
Flat tire
Preparing the vehicle
Park the vehicle in a safe distance from
moving traffic on a hard, flat surface
when possible.
Turn on the hazard warning flasher
(page 146).
Turn the steering wheel so that the
front wheels are in a straight ahead po-
sition.
Set the parking brake (
page 61).
Move the gear selector lever toP.
Vehicles with SmartKey:
Turn off the engine (
page 62).
Remove the SmartKey from the starter
switch.Vehicles with SmartKey with
KEYLESS-GO*:
Turn off the engine by pressing the
KEYLESS-GO* start/stop button on the
gear selector lever once (
page 62).
Open the driver’s door (this puts the ig-
nition in position0, same as with the
SmartKey removed from the starter
switch). The driver’s door then can be
closed again.
Have any passenger exit the vehicle at
a safe distance from the roadway.
Mounting the spare wheel
iOpen door only when conditions are
safe to do so.
Warning!
G
The dimensions of the spare wheel
(Minispare or collapsible tire) are different
from those of the road wheels. As a result,
the vehicle handling characteristics change
when driving with a spare wheel mounted.
Adapt your driving style accordingly.
The spare wheel is for temporary use only.
When driving with spare wheel mounted,
ensure proper tire pressure and do not ex-
ceed a vehicle speed of 50 mph (80 km/h).
Drive to the nearest Mercedes-Benz Center
as soon as possible to have the spare wheel
replaced with a regular road wheel.
Never operate the vehicle with more than
one spare wheel mounted.
Do not switch off the ESP
® when a
Minispare or collapsible tire is mounted.
Page 452 of 521

451 Practical hints
Batteries
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.
!Never loosen or detach battery termi-
nal clamps while the engine is running
or the SmartKey is in the starter switch.
Otherwise the alternator and other
electronic components could be se-
verely damaged.
Have the battery checked regularly by
an authorized Mercedes-Benz Center.
Refer to Maintenance Booklet for main-
tenance intervals or contact an autho-
rized Mercedes-Benz Center for further
information.Warning!
G
Do not place metal objects on the battery as
this could result in a short circuit.
Use leak-proof battery only to avoid the risk
of acid burns in the event of an accident.
Warning!
G
The electrohydraulic brake system requires
electrical power to operate.
A malfunction in the vehicle’s power supply
or electrical system may impair brake sys-
tem operation and switch it into its emer-
gency operation mode. The same applies if
battery is disconnected. To brake, the driver
must then apply significantly greater brake
pedal pressure and depress the pedal much
further to obtain the expected braking ef-
fect. If necessary, apply full pressure to the
brake pedal. Brakes may only be applied to
the front wheels. Stopping distance is in-
creased! Adjust your driving style according-
ly. For more information, refer to
“Electrohydraulic brake system”
(page 97).
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 459 of 521

458 Practical hintsTowing the vehicle
!
To be certain to avoid a possibility of
damage to the drivetrain, however, we
recommend the drive shaft be discon-
nected at the rear axle drive flange (ve-
hicles with 4MATIC: disconnected at
the front and rear axle drive flanges) for
any towing beyond a short tow to a
nearby garage.
Warning!
G
If circumstances require towing the vehicle
with all wheels on the ground, always tow
with a tow bar if:
the engine will not run
there is a malfunction in the electrohy-
draulic brake system
there is a malfunction in the power sup-
ply or in the vehicle’s electrical system
as that will be necessary to adequately con-
trol the towed vehicle.
Prior to towing the vehicle with all wheels on
the ground, make certain the SmartKey is in
starter switch position2.
If the SmartKey is left in the starter switch
position0 for an extended period of time, it
can no longer be turned in the switch. In this
case, the steering is locked. To unlock, re-
move SmartKey from starter switch and re-
insert.
Warning!
G
The brake system requires electrical power
to operate.
A malfunction in the vehicle’s power supply
or electrical system may impair brake sys-
tem operation and switch it into its emer-
gency operation mode. To brake, the driver
must then apply significantly greater brake
pedal pressure and depress the pedal much
further to obtain the expected braking ef-
fect. If necessary, apply full pressure to the
brake pedal. Brakes may only be applied to
the front wheels. Stopping distance is in-
creased! Adapt your driving style according-
ly. For more information, refer to
“Electrohydraulic brake system”
(page 97).
With the engine not running, there is no
power assistance for the steering system. In
this case, it is important to keep in mind that
a considerably higher degree of effort is nec-
essary to steer the vehicle. Adapt your driv-
ing accordingly.