Battery (vehicle)
12 V battery – important safety notes
PLUG-IN HYBRID vehicles are equipped with a
12 V battery and a high-voltage battery. The fol-
lowing notes refer to the 12 V battery. Notes on
the high-voltage battery can be obtained in the
"High-voltage battery – important safety notes"
section (
Ypage 374).
Special tools and expert knowledge are required
when working on the battery, e.g. removal and
installation. You should therefore have all work
involving the battery carried out at a qualified
specialist workshop.
GWARNING
Work carried out incorrectly on the battery
can lead, for example, to a short circuit and
thus damage the vehicle electronics. This can
lead to function restrictions applying to
safety-relevant systems, e.g the lighting sys-
tem, the ABS (anti-lock braking system) or the
ESP
®(Electronic Stability Program). The oper-
ating safety of your vehicle may be restricted.
You could lose control of the vehicle, for
example:
Rwhen braking
Rin the event of abrupt steering maneuvers
and/or when the vehicle's speed is not
adapted to the road conditions
There is a risk of an accident.
In the event of a short circuit or a similar inci-
dent, contact a qualified specialist workshop
immediately. Do not drive any further. You
should have all work involving the battery car- ried out at a qualified specialist workshop.
For further information about ABS and ESP
®,
see (Ypage 68) and (Ypage 73).
All vehicles except Mercedes-AMG vehicles:
GWARNING
Electrostatic build-up can lead to the creation of sparks, which could ignite the highly explo-
sive gases of a battery. There is a risk of an
explosion.
Before handling the battery, touch the vehicle
body to remove any existing electrostatic
build-up.
The highly flammable gas mixture forms when
charging the battery as well as when jump-start-
ing.
Always make sure that neither you nor the bat-
tery is electrostatically charged. A build-up of
electrostatic charge can be caused, for exam-
ple:
Rby wearing clothing made from synthetic
fibers
Rdue to friction between clothing and seats
Rif you push or pull the battery across the car-
pet or other synthetic materials
Rif you wipe the battery with a cloth
GWARNING
During the charging process, a battery produ-
ces hydrogen gas. If a short circuit occurs or
sparks are created, the hydrogen gas can
ignite. There is a risk of an explosion.
RMake sure that the positive terminal of a
connected battery does not come into con- tact with vehicle parts.
RNever place metal objects or tools on a bat-
tery.
RIt is important that you observe the descri-
bed order of the battery terminals when
connecting and disconnecting a battery.
RWhen jump-starting, make sure that the
battery poles with identical polarity are
connected.
RIt is particularly important to observe the
described order when connecting and dis-
connecting the jumper cables.
RNever connect or disconnect the battery
terminals while the engine is running.
GWARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with skin, eyes or clothing. Do
not inhale any battery gases. Do not lean over
the battery. Keep children away from batter-
ies. Wash away battery acid immediately with
372Battery (vehicle)
Breakdo wn assis tance
ing the vehicle or charging the battery, gasescan escape from the battery. There is a risk of
an explosion.
Allow the frozen battery to thaw out before
charging it or jump-starting.
!Only use battery chargers with a maximum
charging voltage of 14.8 V.
All vehicles:
!Only charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment (
Ypage 376).
XOpen the hood.
XConnect the battery charger to the positive
terminal and ground point in the same order
as when connecting the donor battery in the
jump-starting procedure (
Ypage 376).
Keep away from fire and open flames. Do not
lean over a battery. Never charge the battery if it
is still installed in the vehicle, unless you use a
battery charger which has been tested and
approved by Mercedes-Benz. A battery charger
unit specially adapted for Mercedes-Benz vehi-
cles and tested and approved by Mercedes-
Benz is available as an accessory. It permits the
charging of the battery in its installed position.
Contact an authorized Mercedes-Benz Center
for further information and availability. Read the
battery charger's operating instructions before
charging the battery.
All vehicles except Mercedes-AMG vehicles:
if the indicator/warning lamps in the instrument
cluster do not light up at low temperatures, it is
very likely that the discharged battery has fro-
zen. In this case you may neither jump-start the
vehicle nor charge the battery. The service life of
a thawed-out battery may be shorter. The start-
ing characteristics can be impaired, particularly
at low temperatures. Have the thawed- out bat
-
tery checked at a qualified specialist workshop.
Mercedes-AMG vehicles: at low temperatures,
do not charge a battery which has been removed
using a battery charger. Allow the battery to
warm up gently first, if necessary. Otherwise,
the service life can be shortened and the start-
ing characteristics impaired, especially at low
temperatures.
PLUG-IN HYBRID vehicles: if the battery
charge is sufficient, the high-voltage battery can
also supply the 12 V battery. This only happens if the condition of charge of the 12 V battery
requires this, e.g. after using electrical consum-
ers for an extended period with the engine
switched off. As the on-board voltage is contin-
uously monitored this can also be performed
when the engine is switched off. The condition of
charge of the 12 V battery and the on-board
voltage are thereby kept stable for a longer
period.
Battery (vehicle)375
Breakdown assistance
Z
Jump-starting
For the jump-starting procedure, use only the jump-starting connection point in the engine com-
partment, consisting of a positive terminal and a ground point.
All vehicles except Mercedes-AMG vehicles:
GWARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with skin, eyes or clothing. Do not inhale any battery gases. Do not lean over the
battery. Keep children away from batteries. Wash away battery acid immediately with plenty of
clean water and seek medical attention.
GWARNING
During charging and jump-starting, explosive gases can escape from the battery. There is a risk of an explosion.
Particularly avoid fire, open flames, creating sparks and smoking. Ensure there is sufficient ven-
tilation while charging and jump-starting. Do not lean over a battery.
GWARNING
During the charging process, a battery produces hydrogen gas. If a short circuit occurs or sparks
are created, the hydrogen gas can ignite. There is a risk of an explosion.
RMake sure that the positive terminal of a connected battery does not come into contact with
vehicle parts.
RNever place metal objects or tools on a battery.
RIt is important that you observe the described order of the battery terminals when connecting
and disconnecting a battery.
RWhen jump-starting, make sure that the battery poles with identical polarity are connected.
RIt is particularly important to observe the described order when connecting and disconnecting
the jumper cables.
RNever connect or disconnect the battery terminals while the engine is running.
GWARNING
A discharged battery can freeze at temperatures below freezing point. When jump-starting the
vehicle or charging the battery, gases can escape from the battery. There is a risk of an explosion. Allow the frozen battery to thaw out before charging it or jump-starting.
If, at low temperatures, the indicator lamps/warning lamps in the instrument cluster do not light up,
it is highly likely that the discharged battery has frozen. In this case, you may neither charge the
battery nor jump-start the vehicle. The service life of a thawed-out battery may be shorter. The
starting characteristics can be impaired, particularly at low temperatures. Have the thawed-out
battery checked at a qualified specialist workshop.
All vehicles:
!Avoid repeated and lengthy starting attempts. Otherwise, the catalytic converter could be
damaged by the non-combusted fuel.
376Jump-starting
Breakdown assistance
Do not start the vehicle using a rapid charging device. If your vehicle's battery is discharged, the
engine can be jump-started from another vehicle or from a second battery using jumper cables.
Observe the following points:
RThe battery is not accessible in all vehicles. If the other vehicle's battery is not accessible, jump-
start the vehicle using a second battery or a jump-starting device.
RYou may only jump-start the vehicle when the engine and exhaust system are cold.
RAll vehicles except Mercedes-AMG vehicles: do not start the engine if the battery is frozen. Let
the battery thaw first.
ROnly jump-start from batteries with a 12 V voltage rating.
ROnly use jumper cables which have a sufficient cross-section and insulated terminal clamps.
RIf the battery is fully discharged, leave the battery that is being used to jump-start connected for
a few minutes before attempting to start. This charges the battery slightly.
RMake sure that the two vehicles do not touch.
Make sure that:
Rthe jumper cables are not damaged.
Rwhen the jumper cables are connected to the battery, uninsulated sections of the terminal clamp
do not come into contact with other metal sections.
Rthe jumper cables cannot come into contact with parts which can move when the engine is
running, such as the V-belt pulley or the fan.
XSecure the vehicle by applying the electric parking brake.
XShift the transmission to position P.
XMake sure that the ignition is switched off. All indicator lamps in the instrument cluster must be
off. When using the SmartKey, turn the SmartKey to position 0in the ignition lock and remove it
(
Ypage 162).
XSwitch off all electrical consumers, e.g. rear window defroster, lighting, etc.
XOpen the hood.
Example: ground point cover
XTurn fasteners :one Õturn and remove.
XRemove the cover while pressing down on cap ;of the washer fluid reservoir.
Jump-starting377
Breakdown assistance
Z
Position numberDidentifies the charged battery of the other vehicle or an equivalent jump-starting
device.
XSlide cover Cof positive terminal =in the direction of the arrow.
XConnect positive terminal =on your vehicle to positive terminal ?of donor battery Dusing the
jumper cable. Always begin with positive terminal =on your own vehicle first.
XStart the engine of the donor vehicle and run it at idling speed.
XConnect negative terminal Aof donor battery Dto ground point Bof your vehicle using the
jumper cable, connecting the jumper cable to donor battery Dfirst.
XStart the engine.
XBefore disconnecting the jumper cables, let the engine run for several minutes.
XFirst, remove the jumper cables from ground point Band negative terminal A, then from pos-
itive clamp =and positive terminal ?. Begin each time at the contacts on your own vehicle first.
XAfter removing the jumper cables, close cover Cof positive terminal =.
XReplace the earth point cover. Make sure all mountings for the fasteners are positioned precisely
beneath the corresponding recesses in the cover.
XPress fasteners:into the mountings. Turn the fasteners by Õof a turn to engage.
XHave the battery checked at a qualified specialist workshop.
PLUG-IN HYBRID vehicles: if your vehicle has been jump-started, it may not be possible to use the
electric drive for approximately 30 minutes.
Jump-starting is not considered to be a normal operating condition.
iJumper cables and further information regarding jump-starting can be obtained at any qualified
specialist workshop.
378Jump-starting
Breakdown assistance
Towing and tow-starting
Important safety notes
GWARNING
Functions relevant to safety are restricted or
no longer available if:
Rthe engine is not running.
Rthe brake system or the power steering is
malfunctioning.
Rthere is a malfunction in the voltage supply or the vehicle's electrical system.
If your vehicle is being towed, much more
force may be necessary to steer or brake.
There is a risk of an accident.
In such cases, use a tow bar. Before towing,
make sure that the steering moves freely.
GWARNING
When towing or tow-starting another vehicle
and its weight is greater than the permissible
gross weight of your vehicle, the:
Rthe towing eye could detach itself
Rthe vehicle/trailer combination could roll-
over.
There is a risk of an accident.
When towing or tow-starting another vehicle,
its weight should not be greater than the per- missible gross weight of your vehicle.
Details on the permissible gross vehicle weight
of your vehicle can be found on the vehicle iden-
tification plate (
Ypage 426).
!When COLLISION PREVENTION ASSIST
PLUS, DISTRONIC PLUS or the HOLD function
is activated, the vehicle brakes automatically
in certain situations.
To avoid damage to the vehicle, deactivate
these systems in the following or similar sit-
uations:
Rwhen towing the vehicle
Rin the car wash
!Make sure that the electric parking brake is
released. If the electric parking brake is faulty,
visit a qualified specialist workshop.
!Secure the tow rope or tow bar to the towing
eye only. Otherwise, the vehicle could
become damaged.
!Do not use the towing eyes for recovery pur-
poses as this could damage the vehicle. If in
doubt, recove
r the vehicle with a crane.
!When towing, pull away slowly and
smoothly. If the tractive power is too high, the
vehicles could be damaged.
!Shift the automatic transmission to Nand
do not open the driver's or front passenger's
door during towing. The automatic transmis-
sion may otherwise shift to position P, which
could damage the transmission.
!Do not tow with sling-type equipment. This
could damage the vehicle.
!The vehicle can be towed a maximum of
30 miles (50km). The towing speed of 30 mph (50 km/h) must not be exceeded.
If the vehicle has to be towed more than
30 miles (50km), the entire vehicle must be
raised and transported.
It is better to have the vehicle transported than
to have it towed away.
If the vehicle has suffered transmission damage,
have it transported on a transporter or trailer.
The automatic transmission must be in position N when the vehicle is being towed.
If the automatic transmission cannot be shifted
to position N, have the vehicle transported on a
transporter or trailer.
The battery must be connected and charged.
Otherwise, you:
Rcannot turn the SmartKey to position 2in the
ignition lock
Rcannot release the electric parking brake
Rcannot shift the automatic transmission to
position N
Disarm the automatic locking feature before the vehicle is towed (
Ypage 87). You could other-
wise be locked out when pushing or towing the
vehicle.
PLUG-IN HYBRID vehicles:
Towing and tow-starting379
Breakdown assistance
Z
Transporting the vehicle
PLUG-IN HYBRID vehicles
Transportation of the vehicle should only be car-
ried out by professional recovery companies.
4MATIC vehicles/vehicles with auto-
matic transmission
!When the vehicle is loaded for transport, the
front and rear axles must be stationary and on
the same transportation vehicle. Positioning
over the connection point of the transport
vehicle is not permitted. The drive train may
otherwise be damaged.
All vehicles
!You may only secure the vehicle by the
wheels, not by parts of the vehicle such as
axle or steering components. Otherwise, the
vehicle could be damaged.
The towing eye can be used to pull the vehicle
onto a trailer or transporter for transporting pur-
poses.
XTurn the SmartKey to position 2in the ignition
lock.
XShift the automatic transmission to position
N.
As soon as the vehicle has been loaded:
XPrevent the vehicle from rolling away by
applying the electric parking brake.
XShift the automatic transmission to posi-
tion P.
XTurn the SmartKey to position 0in the ignition
lock and remove it.
XSecure the vehicle.
Notes on 4MATIC vehicles
!
Vehicles with 4MATIC must not be towed
with either the front or the rear axle raised, as
doing so will damage the transmission.
Vehicles with 4MATIC may either be towed away with both axles on the ground or be loaded up
and transported.
If the vehicle's transmission, front, or rear axle is
damaged, have the vehicle transported on a
truck or trailer.
In the event of damage to the electrical sys-
tem: if the battery is defective, the automatic
transmission will be locked in position P. To shift
the automatic transmission to position N, you
must provide power to the vehicle's electrical
system in the same way as when jump-starting
(
Ypage 376).
Have the vehicle transported on a transporter or
trailer.
Tow-starting (emergency engine
starting)
!
Vehicles with automatic transmission must
not be tow-started. You could otherwise dam-
age the automatic transmission.
iInformation on "Jump-starting"
(Ypage 376).
Fuses
Important safety notes
GWARNING
If you manipulate or bridge a faulty fuse or if
you replace it with a fuse with a higher amper- age, the electric cables could be overloaded.
This could result in a fire. There is a risk of an
accident and injury.
Always replace faulty fuses with the specified
new fuses having the correct amperage.
Blown fuses must be replaced with fuses of the
same rating, which you can recognize by the
color and value. The fuse ratings are listed in the
fuse allocation chart.
The fuse allocation chart is on the fuse box in the
trunk (
Ypage 381).
Fuses381
Breakdown assistance
Z
If a newly inserted fuse also blows, have the
cause traced and rectified at a qualified special-
ist workshop, e.g. an authorized Mercedes-Benz
Center.
!Only use fuses that have been approved for
Mercedes-Benz vehicles and which have the
correct fuse rating for the system concerned.
Otherwise, components or systems could be
damaged.
The fuses in your vehicle serve to close down
faulty circuits. If a fuse blows, all the compo-
nents on the circuit and their functions stop
operating.
Before changing a fuse
XSwitch off the engine.
XSwitch off all electrical consumers.
XMake sure that the ignition is switched off
(Ypage 162).
or
XWhen using the SmartKey, turn the SmartKey
to position 0in the ignition lock and remove it
(
Ypage 162).
XSecure the vehicle against rolling away
(Ypage 189).
All indicator lamps in the instrument cluster
must be off.
The fuses are located in various fuse boxes:
RFuse box on the driver's side of the dashboard
RFuse box in the front-passenger footwell
RFuse box in the engine compartment on the
left-hand side of the vehicle, when viewed in
the direction of travel
RFuse box in the trunk
Dashboard fuse box
!
Do not use a pointed object such as a screw-
driver to open the cover in the dashboard. You
could damage the dashboard or the cover.
!Make sure that no moisture can enter the
fuse box when the cover is open.
!When closing the cover, make sure that it is
lying correctly on the fuse box. Moisture seep-
ing in or dirt could otherwise impair the oper-
ation of the fuses.
XOpen the driver's door.
XTo open: pull cover :outwards in the direc-
tion of the arrow and remove it.
XTo close: clip in cover :on the front of the
dashboard.
XFold cover :inwards until it engages.
Fuse box in the front-passenger foot-
well
!
Make sure that no moisture can enter the
fuse box when the cover is open.
!When closing the cover, make sure that it is
lying correctly on the fuse box. Moisture seep-
ing in or dirt could otherwise impair the oper-
ation of the fuses.
XOpen the front-passenger door.
XFold cover :down and remove it.
382Fuses
Breakdown assistance