Page 378 of 521
377 Practical hints
What to do if …?
Where will I find...?
Unlocking/locking in an emergency
Opening/closing in an emergency
(Cabriolet)
Resetting activated head restraints
Replacing SmartKey batteries
Replacing bulbs
Replacing wiper blades
Flat tire
Battery
Jump starting
Towing the vehicle
Fuses
Page 379 of 521

378 Practical hints
What to do if …?
Lamps in instrument clusterGeneral information:
If any of the following lamps in the instru-
ment cluster fails to come on during thebulb self-check when switching on the igni-
tion, have the respective bulb checked and
replaced if necessary.
ProblemPossible cause/consequenceSuggested solution
-The yellow ABS indicator lamp
comes on while the engine is
running.The ABS has detected a malfunction and has
switched off. The BAS and the ESP® are also
switched off (see messages in the multifunc-
tion display).
The brake system is still functioning normally
but without the systems specified above.
If the ABS control unit is malfunctioning,
other systems such as the navigation
system* or the automatic transmission may
also be malfunctioning.
Continue driving with added caution.
Wheels will lock during hard braking,
reducing steering capability.
Read and observe messages in the
multifunction display (
page 394).
Have the system checked at an autho-
rized Mercedes-Benz Center as soon
as possible.
Failure to follow these instructions in-
creases the risk of an accident.
The charging voltage has fallen below
10 volts. The ABS has switched off. The BAS
and the ESP
® are also switched off (see mes-
sages in the multifunction display)
The battery might not be charged sufficiently.
Switch off electrical consumers that
are currently not needed, e.g. seat
heating*.
If necessary, have the generator and
battery checked.
When the voltage is above this value
again, the ABS is operational again.
Page 396 of 521

395 Practical hints
What to do if …?
Display messagePossible cause/consequencePossible solution
ESPUnavailable
See Operator’s ManualThe ESP® is temporarily not available.
The system’s self-diagnosis may not be
completed yet.
The ABS and the BAS might not be
operational.
The brake system is still functioning normally
but without the systems specified above.Drive a short distance with added
caution at a vehicle speed of above
12 mph (20 km/h).
When the message disappears, the
ESP
® is available again.
If the message does not disappear:
Continue driving with added caution.
Have the system checked at an autho-
rized Mercedes-Benz Center as soon as
possible.
Failure to follow these instructions increas-
es the risk of an accident.
The charging voltage has fallen below 10 volts.
The ESP® has switched off.
The BAS may be switched off, too. The battery
may not be charged. The battery or the gener-
ator may be malfunctioning.
The ABS might not be operational.
The brake system is still functioning normally
but without the systems specified above.
Continue driving with added caution.
When the voltage is above this value
again, the ESP
® is operational again.
Have the system checked at an autho-
rized Mercedes-Benz Center as soon as
possible.
Page 404 of 521
403 Practical hints
What to do if …?
Symbol messages
Display symbolDisplay messagePossible cause/consequencePossible solution
#The battery is no longer charging.
Possible causes:
broken poly-V-belt
alternator malfunctioning
Stop immediately in a safe location or
as soon as it is safe to do so and 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. Notify
an authorized Mercedes-Benz Center.
If it is intact:
Drive immediately to the nearest
authorized Mercedes-Benz Center.
Low Voltage
Charge BatteryThe battery has insufficient voltage.Start the engine (page 51).
Low Voltage
Switch Off
ConsumersThe battery has insufficient voltage.Turn off unnecessary electrical con-
sumers.
Page 442 of 521

441 Practical hints
Replacing SmartKey batteries
Replacing SmartKey batteries
If the batteries in the SmartKey or the
SmartKey with KEYLESS-GO* are dis-
charged, the vehicle can no longer be
locked or unlocked. It is recommended to
have the batteries replaced at an
authorized Mercedes-Benz Center.Batteries contain materials that can harm
the environment if disposed of improperly.
Recycling of batteries is the preferred
method of disposal. Many states require
sellers of batteries to accept old batteries
for recycling.
Warning!G
Batteries contain poisonous and corrosive
substances. Therefore keep the batteries
out of reach of children.
If a battery is swallowed, seek medical help
immediately.
Warning!G
SmartKey batteries contain Perchlorate
material, which may require special handling
and regard for the environment. Check with
your local government’s disposal guidelines.
California residents, see
http://www.dtsc.ca.gov/HazardousWaste
/Perchlorate/index.cfm.
iWhen inserting the batteries, make sure
they are clean and free of lint.
iWhen changing batteries, always replace
both batteries.
The required replacement batteries are available
at any Mercedes-Benz Center.
Page 443 of 521
442 Practical hints
Replacing SmartKey batteries
SmartKey / SmartKey with
KEYLESS-GO*
Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove the mechanical key from the
SmartKey or SmartKey with
KEYLESS-GO* (
page 427).
1Mechanical key
2Battery compartment
Insert mechanical key1 into the
opening.
Press mechanical key1 in direction of
arrow.
The battery compartment2 is un-
latched.
Pull battery compartment2 out of the
housing.
3Batteries
4Contact spring
Remove the batteries3.
Using a lint-free cloth, insert new
batteries3 under the contact
springs4 with the positive terminal
(+) side facing up.
Return battery compartment2 into
housing until it locks into place.
Slide mechanical key 1 back into the
SmartKey.
Check the operation of the SmartKey.
Page 465 of 521

464 Practical hints
Battery
The battery is located in the engine
compartment on the right hand side.
1Clamps
Removing filter box:
Release clamps1.
Remove filter box.
Installing filter box:
Insert filter box properly.
Secure it with clamps1.
Warning!G
Failure to follow these instructions can re-
sult in severe injury or death.
Observe all safety instructions and
precautions when handling automotive
batteries (
page 329).
Never lean over batteries while connecting,
you might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking, etc.
!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 at an autho-
rized Mercedes-Benz Center.
Refer to Maintenance Booklet for maintenance
intervals or contact an authorized
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.
Page 466 of 521

465 Practical hints
Battery
2Negative terminal
3Positive terminal cover
Disconnecting the battery
Apply the parking brake (page 59).
Make sure gear selector lever is set to
positionP (
page 174).
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 hood (page 323).
Remove the filter box (page 464).
Read and observe safety instructions
and precautions (
page 464).
Disconnect the battery negative lead
from negative terminal2.
Remove cover3 from the positive
terminal.
Disconnect the battery positive lead.
Removing the battery
Remove the screw securing the
battery.
Remove the battery support and
bracket.
Pull out the ventilation hose from the
battery (depending on battery arrange-
ment in your vehicle model, the ventila-
tion hose is located either on the left or
right side of the battery).
Take out the battery.
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
!Always disconnect the battery in the order
described below. Otherwise the vehicle’s elec-
tronics can be damaged.