Page 451 of 521

450 Practical hintsBatteriesYour 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 423).
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 326).
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 455 of 521

454 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
1 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 converter
1.
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 456 of 521
455 Practical hints
Jump starting
The battery is located in the trunk under-
neath the luggage box (
page 423). 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.
Open the trunk.
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 326).
!Never invert the terminal connections!
 
     
        
        Page 457 of 521
456 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 460 of 521

459 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 103).
To prevent the vehicle door locks from 
locking, deactivate the automatic cen-
tral locking (
page 129). 
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 gear 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 450) or “Jump starting” 
(page 454).
For information on manual unlocking of 
the gear selector lever, 
see (page 428).