694 Practical hints
Batteries
Starter battery (example illustration from
S550)
1Negative terminal
2Positive terminal
Disconnecting starter battery
Secure vehicle in place with electronic
parking brake (
page 395).
Shift the automatic transmission toP
(
page 399).
Do not rub the battery with rags or cloths.
The battery could explode if touched due to
electrostatic charge or due to spark forma-
tion.
!Switch off the engine and switch off the ve-
hicle’s internal electrical functions (
page 695)
before you disconnect or remove the battery’s
terminal clamps. You could otherwise destroy
electronic assemblies such as the generator.
Have the battery checked regularly by an autho-
rized Mercedes-Benz Center. Refer to Mainte-
nance Booklet for maintenance intervals or
contact an authorized Mercedes-Benz Center for
further information.
!Do not connect any consumers directly to
the starter battery. The starter battery will other-
wise be discharged.
iOnly replace a discharged battery with a bat-
tery recommended by Mercedes-Benz. The con-
sumer battery is installed in the trunk in such a
way that it is safeguarded as much as possible
against mechanical destruction in the event of
an accident.
iRemove SmartKey from starter switch (vehi-
cles with KEYLESS-GO*: Make sure the vehicle’s
on-board electronics have status 0)
(
page 344) when you turn off the engine and
no longer require any electrical consumers. The
vehicle then uses very little power and the con-
sumer battery is spared.
iIf the consumer battery is discharged, you
must use the mechanical key to unlock the vehi-
cle (
page 671). Since the vehicle has a sepa-
rate starter battery, however, you can still start
the vehicle.
!Always disconnect the starter battery in the
order described below. You could otherwise
damage the vehicle’s electronics.
!Switch off the vehicle’s internal electrical
functions before disconnecting the starter bat-
tery. If the vehicle is stationary for more than one
hour with the SmartKey removed, you do not
need to switch off the vehicle’s internal electrical
functions.
695 Practical hints
Batteries
Switching off vehicle’s internal
electrical functions
Turn off all electrical consumers.
Turn SmartKey in starter switch to po-
sition 0.
Turn SmartKey in starter switch to po-
sition 1.
Wait for 30 seconds.
The vehicle’s internal electrical func-
tions are switched off.
Turn SmartKey in starter switch to po-
sition 0.Disconnecting starter battery
Open the hood (page 541).
Use a 10-mm open-end wrench to dis-
connect the battery negative lead.
Remove cover2 (page 694) from
the positive terminal.
Disconnect the battery positive lead.
Removing starter battery
Pull out the battery ventilation hose
from the battery (depending on battery
arrangement in your vehicle model, the
ventilation hose is located either on the
left or right side of the battery).
Fold bar on starter battery up.
Take out the starter battery.
Charging battery
iVehicles with KEYLESS-GO: remove the
KEYLESS-GO button (
page 345) and use the
SmartKey with KEYLESS-GO like a normal
SmartKey.
!Do not remove the SmartKey!
iFor your convenience, have the starter bat-
tery removed by a Mercedes-Benz Center.
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.
iHave the batteries charged by a
Mercedes-Benz Center. If you charge the batter-
ies yourself, follow the operating instructions for
your charging device.
696 Practical hints
Batteries
Starter battery
Connect the switched-off charging de-
vice to the terminals of the starter bat-
tery. Observe the operating
instructions in the manual for the
charging device while doing so.
Reinstalling starter battery
Install starter battery in engine com-
partment.
Swing retaining bar down.
Reconnecting starter battery
Make sure that the consumer battery in
the trunk is correctly installed and con-
nected.
Turn SmartKey in starter switch to po-
sition 0 and remove.
Connect the positive lead and fasten its
cover2 (
page 694).
Connect negative lead1
(
page 694).
Attach ventilation tube.
Switch on the ignition (page 344).
Start the engine (page 389).
Check vehicle functions.
!Only use charging devices with a maximum
charging voltage of 14.8 V.
Warning!G
During the charge procedure, there is a risk
of acid burns due to gases escaping from
the battery. Do not bend over the battery
during the charge procedure.
!The battery and the battery ventilation hose
must always be securely installed when the vehi-
cle is in operation.
!Always connect the starter battery in the or-
der described below. Otherwise, the vehicle’s
electronics could be damaged.
Warning!G
Do not drive without a properly installed and
connected consumer battery.
Have any work on the consumer battery car-
ried out by an authorized Mercedes-Benz
Center.
!Never invert the terminal connections.
!Make sure that the battery has a plug where
the ventilation tube is attached to it.
698 Practical hints
Jump starting
Jump starting should only be performed on
the starter battery. The starter battery is
located in the engine compartment on the
passenger side (
page 694).
Make sure the two vehicles do not
touch.
Secure vehicle in place with electronic
parking brake (
page 395).
Shift the automatic transmission toP
(
page 399).
Turn off all electrical consumers, ex-
cept hazard warning flashers or work
lights.
Open the hood (page 541).
Start the engine of the vehicle with the
charged battery and run at idle speed.1Positive terminal of your vehicle’s
battery
2Positive terminal of other vehicle’s
battery
3Negative terminal of other vehicle’s
battery
4Negative clamp
Warning!G
Keep flames or sparks away from battery.
Do not smoke.
Observe all safety instructions and precau-
tions when handling automotive batteries
(
page 692).
iVehicles with KEYLESS-GO*: remove the
KEYLESS-GO button (
page 345) and use the
SmartKey with KEYLESS-GO like a normal
SmartKey.
699 Practical hints
Jump starting
Remove red cover from positive
terminal 1.
Connect positive terminal2 of the
charged battery with positive
terminal1 of the discharged battery
with the jumper cable. Clamp cable to
charged battery2 first.
Connect negative terminal3 of
charged battery to jumper cables and
attach other end4 to a suitable
ground point on the vehicle.
Get into vehicle and start engine within
30 seconds.
If the starting attempt does not suc-
ceed:
Turn the SmartKey in starter switch
to position 0.
Take out the SmartKey.
Turn off engine of donor vehicle, re-
start it and let it run at idle speed
for several minutes.
Disconnect the jumper cable during
this time.
Reconnect jumper cable as de-
scribed before.
Restart engine.
While the engine is running, switch off
several electrical consumers such as
the blower.
Disconnect jumper cables first from
ground point4 and negative
terminal3, then from positive
terminals1 and2.
Have the battery checked at the near-
est authorized Mercedes-Benz Center.!Never invert the terminal connections.
700 Practical hints
Towing the vehicle
Mercedes-Benz recommends that the
vehicle be transported with all wheels off
the ground using flatbed or appropriate
wheel lift/dolly equipment. This method is
preferable to other types of towing.
When circumstances do not permit the
recommended towing methods, the
vehicle may be towed with all wheels on
the ground or front wheels raised (except
vehicles with 4MATIC) only so far as neces-
sary to have the vehicle moved to a safe
location where the recommended towing
methods can be employed.
!Do not tow-start the vehicle.
!Vehicles with 4MATIC:
Do not tow with one axle raised. Doing so could
damage the transfer case, which is not covered
by the Mercedes-Benz Limited Warranty.
All wheels must be on or off the ground. Observe
instructions for towing the vehicle with all
wheels on the ground.
!Use flatbed or wheel lift/dolly equipment
with SmartKey or SmartKey with KEYLESS-GO*
in starter switch turned to position0.
Do not tow with sling-type equipment. Towing
with sling-type equipment over bumpy roads will
damage radiator and supports.
To prevent damage during transport, do not tie
down vehicle by its chassis or suspension parts.
Switch off the ESP
® (page 73) and the auto-
matic central locking (
page 245).
!Towing of the vehicle should only be done
using the properly installed towing eye bolt.
Never attach tow cable, tow rope or tow rod to
vehicle chassis, frame or suspension parts.
Warning!G
If circumstances require towing the vehicle
with all wheels on the ground, always tow
with a tow bar if:
the engine will not run
there is a malfunction in the brake
system
there is a malfunction in the power
supply or in the vehicle’s electrical
system
This is necessary to adequately control the
towed vehicle.
Prior to towing the vehicle with all wheels on
the ground, make sure the SmartKey or
SmartKey with KEYLESS-GO* is in starter
switch position2.
701 Practical hints
Towing the vehicle
Warning!G
With the engine not running, there is no
power assistance for the brake and steering
systems. In this case, it is important to keep
in mind that a considerably higher degree of
effort is necessary to brake and steer the
vehicle. Adapt your driving accordingly.
!When towing the vehicle with all wheels on
the ground or with the front axle raised, the start-
er battery must be connected and charged. Oth-
erwise:
you will not be able to switch on the ignition
you will not be able to engage the automatic
transmission in neutral positionN
(
page 402)
you cannot release the electronic parking
brake
For information on charging the starter battery
see “Batteries” (
page 692) or see “Jump start-
ing” (
page 697).
!Make sure that the electronic parking brake
is released. If the electronic parking brake is
malfunctioning, release it mechanically
(
page 673).
!If the vehicle is towed with the front axle
raised (not permissible for vehicles with
4MATIC), the automatic transmission must be in
positionN and the engine must be shut off
(SmartKey or SmartKey with KEYLESS-GO* in
starter switch position0 or1). Active braking
action through the ESP
® may otherwise seriously
damage the brake system.
When towing the vehicle with all wheels on the
ground, the automatic transmission must be
shifted to neutral positionN and the SmartKey
or SmartKey with KEYLESS-GO* must be in start-
er switch position2.
!When towing the vehicle with all wheels on
the ground or the front axle raised, the vehicle
may be towed only for distances up to 30 miles
(50 km) and at a speed not to exceed 30 mph
(50 km/h).
!If the vehicle is towed, the transmission
must be in neutral positionN.
If you turn off the engine using
the SmartKey and
remove the SmartKey from the starter
switch
or
open a front door
the KEYLESS-GO* start/stop button and
open a front door
the transmission will shift to park positionP
automatically.
702 Practical hints
Towing the vehicle
If you want the gear position to remain in
neutral positionN, observe the following
instructions.
Vehicles with SmartKey:
With the vehicle at a standstill and the
ignition switched on shift the
automatic transmission to neutral
positionN.
If engaged, manually release the
electronic parking brake (
page 395).
Switch off the ignition and leave the
SmartKey in the starter switch.Vehicles with KEYLESS-GO*:
With the vehicle at a standstill, depress
the brake pedal and keep it pressed.
Shift the automatic transmission to
park positionP.
Release the brake pedal.
Remove the KEYLESS-GO start/stop
button from the starter switch
(
page 345).
Insert the SmartKey with KEYLESS-GO
into the starter switch.
With the ignition switched on shift the
automatic transmission to neutral
positionN.
If engaged, manually release the
electronic parking brake (
page 395).
Switch off the ignition and leave the
SmartKey with KEYLESS-GO in the
starter switch.
Warning!G
When leaving the SmartKey or SmartKey
with KEYLESS-GO* in the starter switch, do
not leave children unattended in the vehicle.
It is possible for children to switch on the
ignition which could result in unsupervised
use of vehicle equipment. Unsupervised use
of vehicle equipment could result in an
accident and/or serious personal injury.
iWhen towing the vehicle with all wheels on
the ground, please note the following:
With the automatic central locking activated and
the SmartKey or SmartKey with KEYLESS-GO* in
starter switch position 2, the vehicle doors lock
if the left front wheel as well as the right rear
wheel are turning at vehicle speeds of approxi-
mately 9mph (15km/h) or more.
To prevent the vehicle doors from locking,
deactivate the automatic central locking
(
page 245).
iTo signal turns while being towed with the
hazard warning flasher in use, turn SmartKey or
SmartKey with KEYLESS-GO* in starter switch to
position2 and activate the combination switch
for the left or right turn signal in the usual
manner – only the selected turn signal will
operate.
Upon canceling the turn signal, the hazard
warning flasher will operate again.