Page 418 of 506
416 Practical hintsReplacing SmartKey batteries3Battery
4Contact spring
Using a lint-free cloth, insert new bat-
teries under the contact spring with the
plus (+) side facing up.
Return battery compartment into hous-
ing until it locks into place.
SmartKey with KEYLESS-GO*
Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove mechanical key (
page 410).
1Battery
2Tilt battery up
3Mechanical key
Insert the mechanical key3 in side
opening and push grey slide.
Battery compartment is unlatched.
Pull battery compartment out of the
housing in direction of arrow.
Using mechanical key3 apply pres-
sure to position2.
Battery1 tilts up slightly.
Pull out batteries1 in direction of ar-
row.
Using a lint-free cloth, insert new bat-
teries with the plus (+) side facing up.
Return battery compartment into hous-
ing until it locks into place.
Page 435 of 506
433 Practical hints
Batteries
Batteries
Your vehicle is equipped with two batter-
ies:
Main battery (battery for starter and
electrical consumers; located in the
trunk).
Auxiliary battery (back-up battery; sta-
bilizes the electrical system if the main
battery is discharged; located in the en-
gine compartment)
The main battery is in the trunk under the
luggage box. Remove the luggage box
(
page 408).
Vehicles with spare wheel1Negative terminal
2Positive terminalWarning!
G
Jump starting must only be done using the
main battery in the trunk.
Warning!
G
Failure to follow these instructions can re-
sult in severe injury or death.
Observe all safety instructions and precau-
tions when handling automotive batteries
(page 309).
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.
Page 436 of 506
434 Practical hintsBatteries
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 your au-
thorized 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 SBC 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 “SBC brake
system” (
page 90).
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 437 of 506
435 Practical hints
Batteries
Remove the luggage box (
page 408).
Disconnect battery negative lead1.
Remove cover2 from the positive ter-
minal.
Disconnect the battery positive lead.
Removing the battery
Remove the screw-nuts securing the
battery.
Remove the battery bracket.
Take out the battery.
Charging and reinstalling the battery
Charge battery in accordance with the
instructions of the battery charger
manufacturer.
Reinstall the charged battery. Follow
the previously described steps in re-
verse order.
Reconnecting the battery
Turn off all electrical consumers.
Connect the positive lead and fasten its
cover.
Connect the negative lead.
Install the luggage box (
page 408).Batteries contain materials that can harm
the environment if disposed of improperly.
Large 12 volt storage batteries contain
lead. Recycling of batteries is the preferred
method of disposal. Many states require
sellers of batteries to accept old batteries
for recycling.
Warning!
G
Never charge a battery while still installed in
the vehicle. Gases may escape during charg-
ing and cause explosions that may result in
paint damage, corrosion or personal injury.
!Never invert the terminal connections!!The battery, its filler caps and the vent
tube must always be securely installed
when the vehicle is in operation.
iThe following procedures must be car-
ried out following any interruption of
battery power (e.g. due to reconnec-
tion):
Set the clock (
page 159)
(see COMAND operator’s manual).
Resynchronize the ESP
(page 372).
Resynchronize the side windows
(page 220).
Resynchronize the tilt/sliding sun-
roof* (
page 225) or the tilt/slid-
ing panel* (
page 229).
Page 438 of 506
436 Practical hintsJump starting
If the battery is discharged, the engine can
be started with jumper cables and the bat-
tery of another vehicle. Observe the follow-
ing:
Jump starting should only be performed
when the engine and catalytic convert-
er1 are cold.
Do not start the engine if the battery is
frozen. Let the battery thaw out first.
Only jump start from batteries with the
same voltage rating (12 V). Jump start-
ing with a more powerful battery could
damage the vehicle’s electrical system,
which will not be covered by the
Mercedes-Benz Limited Warranty.
Use only jumper cables with sufficient
cross-section and insulated terminal
clamps.
Always make sure the jumper cables
are not on or near pulleys, fans or other
parts that move when the engine is
started or running.
Warning!
G
Failure to follow these directions will cause
damage to the electronic components, and
can lead to a battery explosion and severe
injury or death.
Never lean over batteries while connecting
or jump starting, 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 very explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking, etc.
Attempting to jump start a frozen battery
can result in it exploding, causing personal
injury.
Read all instructions before proceeding.
1Vehicles with gasoline engine only
!Jump starting may only be performed
on the main battery installed in the
trunk.
Avoid repeated and lengthy starting at-
tempts.
Do not attempt to start the engine us-
ing a battery quick charge unit.
If the engine does not run after several
unsuccessful starting attempts, have it
checked at the nearest authorized
Mercedes-Benz Center.
Excessive unburned fuel generated by
repeated failed starting attempts may
damage the catalytic converter1.
Make sure the jumper cables do not
have loose or missing insulation.
Make sure the cable clamps do not
touch any other metal part while the
other end is still attached to a battery.
Page 439 of 506
437 Practical hints
Jump starting
The battery is located in the trunk under-
neath the luggage box (
page 408). Only
jump start the vehicle from the battery in
the trunk.
Make sure the two vehicles do not
touch.
Turn off all electrical consumers.
Apply parking brake.
Shift gear selector lever to positionP.
Connect positive terminals1 and3
of the batteries with the jumper cable.
Clamp cable to charged battery3
first.
1Positive terminal of discharged battery
2Negative terminal of discharged bat-
tery
3Positive terminal of charged battery
4Negative terminal of charged battery
Warning!
G
Keep flames or sparks away from battery.
Do not smoke.
Observe all safety instructions and precau-
tions when handling automotive batteries
(page 309).
!Never invert the terminal connections!
Page 440 of 506
438 Practical hintsJump starting
Start engine of the vehicle with the
charged battery and run at idle speed.
Connect negative terminals4 and2
of the batteries with the jumper cable.
Clamp cable to charged battery4
first.
Start the engine of the disabled vehi-
cle.Now you can again turn on the electrical
consumers. Do not turn on the lights under
any circumstances.
Remove the jumper cables first from
negative terminals2 and4 and then
from positive terminals1 and3.
Now you can turn on the lights.
Have the battery checked at the near-
est authorized Mercedes-Benz Center.
iThe message
Malfunction - electric
consumers switched off
may appear
in the instrument cluster. It will disap-
pear as soon as the battery is suffi-
ciently charged.
!Do not tow-start the vehicle.
Page 443 of 506
441 Practical hints
Towing the vehicle
iTo signal turns while being towed with
the hazard warning flasher in use, turn
SmartKey in starter switch to
position2 and activate the combina-
tion switch for the left or right turn sig-
nal in the usual manner – only the
selected turn signal will operate.
Upon canceling the turn signal, the haz-
ard warning flasher will operate again.
!When towing the vehicle with all wheels
on the ground, please note the follow-
ing:
With the automatic central locking acti-
vated and the SmartKey in starter
switch position2, or KEYLESS-GO*
start/stop button in position2, the ve-
hicle doors lock if the left front wheel
as well as the right rear wheel are turn-
ing at vehicle speeds of approximately
9 mph (15 km/h) or more.
Switch off the tow-away alarm
(page 95).
To prevent the vehicle door locks from
locking, deactivate the automatic cen-
tral locking (
page 118).
Towing of the vehicle should only be
done using the properly installed tow-
ing eye bolt. Never attach tow cable,
tow rope or tow rod to the vehicle chas-
sis, frame or suspension parts.
iThe selector lever will remain locked in
positionP and the SmartKey will not
turn in the starter switch if the battery
is disconnected or discharged. For
more information see “Battery”
(page 433) or “Jump starting”
(page 436).
Manual unlocking of the transmission
selector lever (
page 412).
