399 Practical hints
Replacing SmartKey batteries
SmartKey
Replacement batteries: Lithium, type
CR 2025 or equivalent.
Remove mechanical key1
(page 394).
1Mechanical key
2Slide
3Battery compartment
Insert mechanical key1 in direction
of arrow in side opening.
Using mechanical key1, push gray
slide2 to unlatch battery
compartment3.
Pull battery compartment3 out of the
housing in direction of arrow.
Remove the discharged batteries in di-
rection of arrow.
4Battery
5Contact spring
Using a lint-free cloth, insert new
batteries4 under contact spring5
with the positive terminal (+) facing up.
Return battery compartment2 into
the housing until it locks into place.
Slide mechanical key1 back into the
SmartKey.
Check the operation of the SmartKey.
421 Practical hints
Battery
Battery
The battery is located in the engine com-
partment on the right-hand side below the
windshield washer fluid reservoir.
1Battery
2Positive terminal
3Negative terminal
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,
see “Battery” (
page 314).
Never lean over batteries while connecting
them, as you could otherwise be injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come into contact with
eyes, skin or clothing. In case it does, imme-
diately 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.
Warning!
G
Do not place metal objects on the battery as
this could result in a short circuit.
Use leak-proof batteries only to avoid the
risk of acid burns in the event of an acci-
dent.!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.
423 Practical hints
Battery
Charging and reinstalling 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.
Reinstall the water tray.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 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
authorized Mercedes-Benz Center for infor-
mation and availability. Charge battery in
accordance with the separate instructions
for the accessory battery charger.
!The battery, its filler caps and the vent
tube must always be securely installed
when the vehicle is in operation.!Never invert the terminal connections!
iThe following procedures must be car-
ried out following any interruption of
battery power (e.g. due to reconnec-
tion):
Set the clock (
page 139).
Synchronize the power windows
(page 251).
424 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-
er 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 (12V). 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.
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 oth-
er parts that move when an 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, as you could otherwise be
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.
!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 converter and
may present a fire risk.
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.
425 Practical hints
Jump starting
Make sure the two vehicles do not
touch.
Turn off all electrical consumers.
Apply parking brake.
Shift gear selector lever* to positionP
(manual transmission to Neutral).
Open the hood (
page 307).
Flip up cover from positive under hood
terminal2 in front of water tray1
(page 422).1Positive terminal of charged battery
2Positive under hood terminal in front of
water tray
3Negative under hood terminal in front
of water tray
4Negative terminal of charged battery
Connect positive terminal1 of the
charged battery with positive under
hood terminal2 in front of the water
tray with one jumper cable. Clamp the
cable to positive terminal1 of the
charged battery first.
Start the engine of the vehicle with the
charged battery and run at idle speed.
Connect negative terminal4 of the
charged battery with negative under
hood terminal3 in front of the water
tray with the second jumper cable.
Clamp the cable to negative
terminal4 of the charged battery
first.
Start the engine of the disabled vehi-
cle.
You can now turn on the electrical con-
sumers. Do not turn on the lights under
any circumstances.
Remove the jumper cables first from
negative terminals3 and4 and then
from positive terminals2 and1.
You can now turn on the lights.
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 314).
!Never invert the terminal connections.
iVehicles with automatic transmission*:
Do not tow-start vehicle.
475 Index
Service
Information 12
Maintenance Booklet 12
Service and warranty
Booklet 435
Information 10
Service life (Tires) 318
Service system
Maintenance service indicator 350
Parts service 434
Settings menu (Control system) 134
Shelf behind roll bar 268
Shelf below rear window, cleaning 360
Shift lock* 462
Side marker lamps 401
Side windows see Power windows
Sidewall 345
SmartKey 92
Checking batteries 97
Factory setting 94
Global locking 95
Global unlocking 94
Locking and unlocking 92Loss of SmartKey or mechanical
key 97
Mechanical key 394
Panic button 80
Positions in starter switch 36
Power windows,
opening/closing* 249
Remote control 92
Replacing batteries 398
Restoring to factory setting 96
Retractable hardtop,
opening/closing* 257
Selective setting 95
Starting engine 50
Turning off engine 61
Unlocking the trunk lid 96
Snow chains 349
Spare fuses (Vehicle tool kit) 388
Spare parts see Parts service
Spare wheel 391
SRS 73, 462
Display message 372
Indicator lamp 366Standard display menu (Control
system) 128
Standing lamps 110, 401
Standing water, driving instructions 300
Starter switch positions 36
Starting 36, 50
Difficulties with 52
Position in starter switch 36
Steering column see Steering wheel
Steering wheel
Adjusting 42
Heating* 288
Steering wheel gearshift control
SLK 280* 165
SLK 350* 165
SLK 55 AMG 167
Stolen vehicle, Recovery services
(Tele Aid) 280
Storage compartments 266
Storing tires 319
Summer opening*
Power windows 249
Retractable hardtop 257
Sun visors 176
Supplemental Restraint System see SRS
Symbols in display 374