Page 441 of 514

440 Practical hintsReplacing SmartKey batteriesIf the batteries in the SmartKey/SmartKey
with KEYLESS-GO* are discharged, the ve-
hicle can no longer be locked or unlocked.
It is recommended to have the batteries re-
placed 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.SmartKey/SmartKey with
KEYLESS-GO*
Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove the mechanical key1 out of
the SmartKey/SmartKey with
KEYLESS-GO* (
page 435).
1Mechanical key
2Battery compartment
Insert mechanical key1 into opening.
Press mechanical key1 in direction of
arrow.
The battery compartment is unlatched.
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.
i
When inserting the batteries, make sure
they are clean and free of lint.
i
When replacing batteries, always replace
both batteries.
The required replacement batteries are available
at any Mercedes-Benz Center.
Page 442 of 514
441 Practical hints
Replacing SmartKey batteries
Pull battery compartment2
(page 440) out of the housing.
3Battery
4Contact spring
Pull out batteries3.
Using a lint-free cloth, insert new bat-
teries 3 under contact spring4 with
the positive terminal (+) side facing up.
Return battery compartment2
(page 440) into housing until it locks
into place.
Slide mechanical key1 (
page 440)
back into the SmartKey/SmartKey
with KEYLESS-GO*.
Check the operation of the
SmartKey/SmartKey with
KEYLESS-GO*.
Page 463 of 514
462 Practical hintsBatteryThe battery is located in the cargo com-
partment on the right-hand side under a
cover.
Pull cover up and detach it.1Positive terminal
2Negative terminal
3Lateral plug
4Battery ventilation hose
Warning!
G
Jump starting must only be done using the
designated terminal connections in the en-
gine compartment (
page 467).
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 330).
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 464 of 514

463 Practical hints
Battery
!
The battery is a v
alve-r
egulated l
ead a
cid
(VRLA) battery, also referred to as “fleece” bat-
tery. Such batteries do not require topping-up of
the electrolyte level. VRLA batteries therefore do
not have cell caps and the battery cover is
non-removable. Do not attempt to open the bat-
tery as otherwise the battery will be damaged.
Even though VRLA batteries do not require top-
ping-up of the electrolyte level and cannot be
opened to check the electrolyte level, the bat-
tery condition must be checked periodically by
performing a battery conductance test. Refer to
Maintenance Booklet for battery condition test-
ing intervals.
As with any other battery, disconnect the battery
if you do not intend to operate your vehicle for an
extended period of time to prevent battery dis-
charge or connect an accessory battery charge
unit expressly approved by Mercedes-Benz for
your vehicle model to maintain the battery
charge. Contact an authorized Mercedes-Benz
Center for further information.
!
The factory-equipped VRLA battery is
leak-proofed. Only use a battery as replacement
that has the same security features and is of
identical size, voltage, and capacity as the facto-
ry-equipped battery.
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 Smart-
Key is in the starter switch. Otherwise the alter-
nator 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 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 465 of 514

464 Practical hintsBatteryDisconnecting the battery
Depress the parking brake pedal.
Make sure the gear selector lever is set
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 cargo compartment.
Read and observe safety instructions
and precautions (
page 330) and
(
page 462).
Access the cargo compartment under-
neath the third row seat cushions and
footwell (
page 431).
Remove cover to access battery
(page 462).
Disconnect battery negative lead from
negative terminal2 (
page 462).
Remove cover1 (
page 462) from
the positive terminal.
Disconnect the battery positive lead.
Removing the battery
1Spacer
2Battery
3Battery bracket
Remove the screw-nuts securing the
battery.
Remove the battery bracket3.
Remove spacer1 from the battery’s
ventilation hose.
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
electronics can be damaged.
Page 466 of 514

465 Practical hints
Battery
Pull out the battery ventilation hose4
(page 462) from the battery (de-
pending on battery arrangement in
your vehicle model, the ventilation
hose is located either on the left or
right side of the battery).
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 battery positive lead and
fasten its cover.
Connect the battery negative lead.
Warning!
G
Never charge a battery while still installed in
the vehicle unless the accessory battery
charge unit* approved by Mercedes-Benz is
being used. Gases may escape during charg-
ing and cause explosions that may result in
paint damage, corrosion or personal injury.
An accessory battery charge unit* specially
adapted for Mercedes-Benz vehicles and
tested and approved by Mercedes-Benz is
available, permitting the charging of the bat-
tery in its installed position. Contact an au-
thorized Mercedes-Benz Center for
information and availability. Charge battery
in accordance with the separate instruc-
tions for the accessory battery charger*.!
The battery and the battery ventilation hose
must always be securely installed when the vehi-
cle is in operation.
!
Always connect the battery in the order de-
scribed below. Otherwise the vehicle’s electron-
ics can be damaged.
!
Never invert the terminal connections!
i
The following procedures must be carried
out following any interruption of battery power
(e.g. due to reconnection):
Set the clock (
page 174) (see COMAND
operator’s manual).
Synchronize the side windows
(page 241).
Synchronize the tilt/sliding sunroof
(page 245).
Page 467 of 514

466 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
converter 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 higher voltage battery could
damage the vehicle’s electrical system,
which will not be covered by the
Mercedes-Benz Limited Warranty.
Only use 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.
!
Do not tow-start the vehicle.
!
Jump starting may only be performed on the
designated jump start terminals located in the
engine compartment (
page 467).
Avoid repeated and lengthy starting attempts.
Do not attempt to start the engine using a bat-
tery quick charge unit.
If the engine does not run after several unsuc-
cessful starting attempts, have it checked at the
nearest authorized Mercedes-Benz Center.
Excessive unburned fuel generated by repeated
failed starting attempts may damage the catalyt-
ic converter.
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 at-
tached to a battery.
Page 468 of 514

467 Practical hints
Jump starting
The jump-start contacts are located in the
engine compartment.
Make sure the two vehicles do not
touch.
Turn off all electrical consumers.
Apply the parking brake (
page 62).
Make sure the gear selector lever is set
to positionP.
Open the hood (
page 324).1Negative (-) terminal
2Cover of positive (+) terminal
Open cover of the positive terminal.
Connect positive terminal 2 and the
positive terminal of the charged battery
with the jumper cable. Clamp cable to
charged battery first.
Start engine of the vehicle with the
charged battery and run at idle speed.
Connect negative terminal1 and the
negative terminal of the charged
battery with the second jumper cable.
Clamp cable to charged battery first.
Start the engine of the disabled
vehicle.
You can now turn on the electrical con-
sumers. Do not switch on the headlamps
under any circumstances.
Remove the jumper cables first from
negative terminals on each battery and
then from the positive terminals on
each battery.
You can now switch on the headlamps.
Have the battery checked at the near-
est authorized Mercedes-Benz Center.
Warning!
G
Keep flames or sparks away from battery.
Do not smoke.
Observe all safety instructions and precau-
tions when handling automotive batteries
(page 330).
!
Never invert the terminal connections!