battery MERCEDES-BENZ CLS-Class 2012 W218 Service Manual

Consult an authorized Mercedes-Benz Center
if you wish to leave your vehicle parked for a
long period of time.GWARNING
Comply with safety precautions and take
protective measures when handling batteries.
Risk of explosionFire, naked flames and
smoking are prohibited
when handling the battery.
Avoid creating sparks.Battery acid is caustic.
Avoid contact with the skin,
eyes or clothing.
Wear suitable protective
clothing, in particular
gloves, an apron and a face
mask.
Immediately rinse acid
splashes off with clean
water. Consult a doctor if
necessary.Wear eye protection.Keep children away.Observe this Operator's
Manual.HEnvironmental noteBatteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separatelyand recycled to protect the
environment.Dispose of batteries in an
environmentally friendly
manner. Return discharged
batteries to a qualified
specialist workshop, e.g. an
authorized Mercedes-Benz
Center, or to a special
collection point for old
batteries.GWARNING
Failure to follow these instructions can result
in severe injury or death.
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.
GWARNING
Do not place any 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 accident.
Take care that you do not become statically
charged, e.g. by wearing synthetic clothing or
rubbing against textiles. For this reason, you
also should not pull or push the battery over
carpets or other synthetic materials.
Never touch the battery first. First, touch the
outside body of the vehicle in order to release
any possible electrostatic charges.
Do not rub the battery with rags or cloths. The
battery could explode if touched due to
electrostatic charge or due to spark
formation.
Battery303Breakdown assistanceZ

! Before working on the battery, e.g.
loosening the battery terminals, switch off
the engine and remove the SmartKey from
the ignition. On vehicles with KEYLESS-GO,
make sure that the ignition is switched off.
Check that all the indicator lamps in the
instrument cluster are off. You may
otherwise destroy electronic components,
such as the alternator.
! Like other batteries, the vehicle battery
may discharge over time if you do not use
the vehicle. In this case have the battery
checked at a qualified specialist workshop,
such as an authorized Mercedes-Benz
Center. You can also charge the battery
with a charger recommended by Mercedes-
Benz. Contact an authorized Mercedes-
Benz Center for more information.
The battery and the cover of the positive
terminal clamp must be installed securely
during operation.
i Remove the SmartKey if you park the
vehicle and do not require any electrical
consumers. The vehicle will then use very
little energy, thus conserving battery
power.
Mercedes-Benz recommends that you do not
carry out work on batteries yourself, e.g.
removing or charging. Always have this work
performed at a qualified specialist workshop,
e.g. an authorized Mercedes-Benz Center.
Charging the battery
GWARNING
Never charge a battery still installed in the
vehicle unless a battery charger unit approved
by Mercedes-Benz is being used. Gases may
escape during charging and cause explosions
that may result in paint damage, corrosion or
personal injury.
A battery charger unit specially adapted for
Mercedes-Benz vehicles 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.
Charge the battery in accordance with the
separate instructions for the battery charger.GWARNING
There is a risk of acid burns during the
charging process due to the gases which
escape from the battery. Do not lean over the
battery during the charging process.
GWARNING
Battery acid is caustic. Avoid contact with the
skin, eyes or clothing.
! Only charge the installed battery with a
battery charger which has been tested and
approved by Mercedes-Benz. These battery
chargers allow the battery to be charged
while still installed.
! Only use battery chargers with a
maximum charging voltage of 14.8 V.
! Only charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment ( Y page 305).
XOpen the hood ( Y page 280).XConnect the battery charger to the positive
terminal and earth point in the same order
as when connecting the donor battery in
the jump-starting procedure
( Y page 305).XRead the battery charger's operating
instructions before charging the battery.304BatteryBreakdown assistance

Jump-startingGWARNING
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 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 attempts. Otherwise, non-combusted fuel may
damage the catalytic converter 23
and create a risk of fire.
Do not use a rapid-charging device to start the engine.
Make sure the jumper cables are not damaged.
Make sure the jumper cables are not touching any other metal objects when they are
connected to the battery.
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:
XThe 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.XOnly jump-start the vehicle when the engine is cold and the catalytic converter system has
cooled down 24
.XDo not start the engine if the battery is frozen. Let the battery thaw first.XJump-starting may only be performed from batteries with a nominal voltage of 12 V.XOnly use jumper cables which have a sufficient cross-section and insulated terminal clamps.XMake sure that the jumper cables cannot come into contact with parts, such as the pulley
or the fan. These parts move when the engine is started and while it is running.XIf 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 empty battery a little.
i Jumper cables and further information about jump-starting can be obtained from any
authorized Mercedes-Benz Center, for example.
XMake sure that the two vehicles do not touch.XApply the parking brake firmly.XShift the transmission to position P.23
Only vehicles with a gasoline engine.
24 Only vehicles with a gasoline engine.Jump-starting305Breakdown assistanceZ

XSwitch off all electrical consumers (e.g. radio, blower, etc.).XOpen the hood (Y page 280).
Position number B identifies the charged battery of the other vehicle or an equivalent jump-
starting device.
XSlide cover : of positive terminal ; in the direction of the arrow.XConnect positive terminal ; on your vehicle to positive terminal = of donor battery B
using the jumper cable, beginning with your own battery.XStart the engine of the donor vehicle and run it at idling speed.XConnect negative terminal ? of donor battery B to earth point A of your vehicle using
the jumper cable, connecting the jumper cable to donor battery B first.XStart the engine.XAllow the engine to run for a few minutes before disconnecting the jumper cable.XFirst, remove the jumper cable from earth point A and negative terminal ?, then from
positive terminal ; and positive terminal =, each time disconnecting from the contacts
on your own vehicle first.XAfter removing the jumper cable, close cover : on positive terminal ;.XHave the battery checked at a qualified specialist workshop, e.g. an authorized Mercedes-
Benz Center. The jump-starting procedure is not a standard operating state; therefore, have
the battery checked.Towing and tow-starting
Important safety notes
GWARNING
If you tow the vehicle, you must use a rigid
towing bar if:
R the engine is not running.
R there is a brake system malfunction.
R there is a malfunction in the power supply
or the vehicle's electrical system.
The power assistance for the steering and the
brake force booster do not work when the306Towing and tow-startingBreakdown assistance

engine is not running. You will need more
force to steer and brake, you may have to
depress the brake pedal with maximum force.
Before towing away, make sure that the
steering can be moved and is not locked.
If you tow or tow-start another vehicle, its
weight must not exceed the maximum
permissible gross vehicle weight of your
vehicle.GWARNING
The vehicle is braked when the HOLD function
or DISTRONIC PLUS is activated. Therefore,
deactivate HOLD and DISTRONIC PLUS if the
vehicle is to be towed.
It is better to have the vehicle transported
than to have it towed.
! You may only tow the vehicle a maximum
distance of 30 miles (50 km). A towing
speed of 30 mph (50 km/h) must not be
exceeded.
For towing distances over 30 miles
(50 km), the vehicle must loaded onto a
transporter.
! Only secure the tow rope or tow bar at the
towing eyes. Otherwise, the vehicle could
be damaged.
! Do not use the towing eye for recovery,
as this could damage the vehicle. If in
doubt, recover the vehicle with a crane.
! When towing, pull away slowly and
smoothly. If the tractive power is too high,
the vehicles could be damaged.
! Do not tow with sling-type equipment.
This could damage the vehicle.
! When towing vehicles with KEYLESS-GO,
use the key instead of the Start/Stop
button. Otherwise, the automatic
transmission may shift to position P when
the driver's or front-passenger door are
opened, which could lead to damage to the
transmission.
The automatic transmission must be in
position N when the vehicle is being towed.
The battery must be connected and charged.
Otherwise, you:
R cannot turn the SmartKey to position 2 in
the ignition lock
R cannot shift the automatic transmission to
position N
i Before the vehicle is towed, switch off the
automatic locking feature (Y page 80). You
could otherwise be locked out when
pushing or towing the vehicle.
Installing/removing the towing eye
Installing the towing eye
XRemove the towing eye from the vehicle
tool kit ( Y page 294).GWARNING
The exhaust tail pipe may be hot. You could
burn yourself if you touch the tail pipe. Be
particularly careful when removing the rear
cover.
The mountings for the removable towing eyes
are located in the bumpers. They are at the
front and at the rear, under the covers.
Example: towing eye covers
Towing and tow-starting307Breakdown assistanceZ

XRelease the parking brake.XLeave the SmartKey in position 2 in the
ignition lock.
Transporting the vehicle
The towing eye can be used to pull the vehicle
onto a trailer or transporter for transporting
purposes.
XTurn the SmartKey to position 2 in the
ignition lock.XShift the automatic transmission to
position N.
As soon as the vehicle is loaded:
XPrevent the vehicle from rolling away by
applying the parking brake.XShift the automatic transmission to
position P.XTurn the SmartKey to position 0 in the
ignition lock and remove the SmartKey
from the ignition lock.XSecure the vehicle.
! Only lash the vehicle down by the wheels
or wheel rims, not by parts of the vehicle
such as axle or steering components.
Otherwise, the vehicle could be damaged.
Notes for 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.
If the vehicle has transmission damage or
damage to the front or rear axle, have it
transported on a transporter or trailer.
In the event of damage to the electrical
system
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 ( Y page 305).
Have the vehicle transported on a transporter
or trailer.
Tow-starting (emergency engine
starting)
! Vehicles with automatic transmission
must not be started by tow-starting. This
could otherwise damage the transmission.
Fuses
Important safety notes
The fuses in your vehicle serve to close down
faulty circuits. If a fuse blows, all the
components on the circuit and their functions
stop operating.
GWARNING
Only use fuses approved by Mercedes-Benz
with the specified amperage for the system in
question and do not attempt to repair or
bridge a blown fuse. Using other than
approved fuses or using repaired or bridged
fuses may cause an overload leading to a fire,
and/or cause damage to electrical
components and/or systems. Have the cause
determined and remedied by an authorized
Mercedes-Benz Center.
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. An authorized
Mercedes-Benz Center will be happy to
advise you.
i If a fuse has blown, contact a breakdown
service or an authorized Mercedes-Benz
Center.
If the newly inserted fuse also blows, have the
cause traced and rectified at a qualified
specialist workshop, e.g. an authorized
Mercedes-Benz Center.
! Only use fuses that have been approved
for Mercedes-Benz vehicles and which
Fuses309Breakdown assistanceZ

Maximum load rating
The maximum load rating in kilograms or
pounds is the maximum weight for which a
tire is approved.
Maximum permissible tire pressure
Maximum permissible tire pressure for one
tire.
Maximum load on one tire
Maximum load on one tire. This is calculated
by dividing the maximum axle load of one axle
by two.
PSI (pounds per square inch)
A standard unit of measure for tire pressure.
Aspect ratio
Relationship between tire height and tire
width in percent.
Tire pressure
This is pressure inside the tire applying an
outward force to each square inch of the tire's
surface. The tire pressure is specified in
pounds per square inch (psi), in kilopascal
(kPa) or in bar. The tire pressure should only
be corrected when the tires are cold. For this,
the vehicle must have been stationary for at
least three hours or not have traveled more
than 1.6 km (1 mile) in this time.
Tire pressure of cold tires
Tire pressure when the vehicle has been
stationary for at least three hours or not have
traveled more than 1.6 km (1 mile) in this
time.
Tread
The part of the tire that comes into contact
with the road.
Bead
The tire bead ensures that the tire sits
securely on the wheel. There are several steel
wires in the bead to prevent the tire from
coming loose from the wheel rim.
Sidewall
The part of the tire between the tread and the
bead.
Weight of optional extras
The combined weight of those optional extras
that weigh more than the replaced standard
part and more than 2.3 kilograms (5 lbs).
These optional extras, such as high-
performance brakes, level control, a roof rack
or a high-performance battery, are not
included in the curb weight and accessory
weight.
TIN (Tire Identification Number)
This is a unique identifier which can be used
by a tire manufacturer to identify tires, for
example for a product recall, and thus identify
the purchasers. The TIN is made up of the
manufacturer's identity code, tire size, tire
type code and the manufacturing date.
Load bearing index
The load bearing index (also load index) is a
code that contains the maximum load bearing
capacity of a tire.
Definition of terms for tires and loading337Wheels and tiresZ