Battery (vehicle)
Important safety notes
Special tools and expert knowledge are
required when working on the battery, e.g.
removal and installation. You should there-
fore have all work involving the battery car-
ried 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 61) and (Ypage 65).
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-
starting. Always make sure that neither you nor the
battery is electrostatically charged. A build-
up of electrostatic charge can be caused, for
example:
Rby wearing clothing made from synthetic
fibers
Rdue to friction between clothing and seats
Rif you push or pull the battery across the
carpet 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
plenty of clean water and seek medical atten-
tion.
296Battery (vehicle)
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Jump-starting
For the jump-starting procedure, use only the jump-starting connection point, consisting of a
positive terminal and an earth point, in the engine compartment.
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.
!Avoid repeated and lengthy starting attempts. Otherwise, the catalytic converter could be
damaged by the non-combusted fuel.
If the indicator/warning lamps do not light up at low temperatures, it is very 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.
Jump-starting299
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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.
RDo 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.
RBare parts of the terminal clamp do not come into contact with other metal parts while the
jumper cables are connected to the battery.
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.
XSwitch off all electrical consumers, e.g. rear window defroster, lighting, etc.
XOpen the hood.
Position number Bidentifies 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, always begin with positive terminal ;on your own vehicle first.
300Jump-starting
Breakdown assistance
XStart the engine of the donor vehicle and run it at idling speed.
XConnect negative terminal?of donor battery Bto ground point Aof your vehicle using
the jumper cable, connecting the jumper cable to battery of other vehicle Bfirst.
XStart the engine.
XBefore disconnecting the jumper cables, let the engine run for several minutes.
XFirst, remove the jumper cables from ground point Aand negative terminal ?, then from
positive clamp ;and positive terminal =. Begin each time at the contacts on your own
vehicle first.
XClose cover :of positive terminal ;after removing the jumper cables.
XHave the battery checked at a qualified specialist workshop.
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.
Towing and tow-starting
Important safety notes
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.
Vehicles with 7G-TRONIC:
!On vehicles with KEYLESS-GO, use the
SmartKey instead of the Start/Stop but-
ton. Turn the SmartKey to position 2in the
ignition lock and shift the automatic trans-
mission to N. Then, turn the SmartKey back
to 0and leave it in the ignition lock.
Vehicles with 9G-TRONIC:
!When towing vehicles with KEYLESS-GO,
use the key instead of the Start/Stop but-
ton. Otherwise, the automatic transmission
may shift to position Pwhen the driver's or front-passenger door are opened, which
could lead to damage to the transmission.
All vehicles:
!Only secure the tow rope or tow bar at the
towing eyes. Otherwise, the vehicle could
be damaged.
!If DISTRONIC PLUS or the HOLD function
is activated, the vehicle brakes automati-
cally in certain situations.
To prevent damage to the vehicle, deacti-
vate DISTRONIC PLUS and the HOLD func- tion in the following or other simila
r situa-
tions:
Rwhen towing the vehicle
Rin the car wash
!Do not use the towing eye for recovery,
this could damage the vehicle. If in doubt,
recover the vehicle with a crane.
!Drive slowly and smoothly when towing.
Excessive tractive power could otherwise
damage the vehicles.
!Do not tow with sling-type equipment.
This could damage the vehicle.
!Make sure that the electric parking brake
is released. If the electric parking brake is
faulty, visit a qualified specialist workshop.
Towing and tow-starting301
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Always switch off the ignition when towing thevehicle with a tow cable or a tow bar.
Vehicles with 9G-TRONIC: the automatic
transmission automatically shifts to position
P when you open the driver's or front-
passenger door or when you remove the key
from the ignition lock.
Vehicles with automatic transmission: in
order to ensure that the automatic transmis-
sion stays in position Nwhen towing away the
vehicle, you must observe the following
points:
XSwitch on the hazard warning lamps
(
Ypage 111).
XTurn the SmartKey to position 2in the igni-
tion lock.
On vehicles with KEYLESS-GO, use the
SmartKey instead of the Start/Stop button
(
Ypage 140).
XDepress and hold the brake pedal.
XShift the transmission to position N.
XRelease the brake pedal.
XRelease the electric parking brake.
XLeave the SmartKey in position2in the
ignition lock.
In order to signal a change of direction when
towing the vehicle with the hazard warning
lamps switched on, use the combination
switch as usual. In this case, only the indica-
tor lamps for the direction of travel flash.
When you reset the combination switch, the
hazard warning flashers start flashing again.
It is important that y
ou observe the safety
instructions when towing away your vehicle
(
Ypage 301).
Towing the vehicle with the rear axle
raised
!
The ignition must be switched off if you
are towing the vehicle with the rear axle
raised. Intervention by ESP
®could other-
wise damage the brake system.
!Vehicles with automatic transmission
must not be towed with the rear axle raised.
The vehicle/trailer combination may oth-
erwise swerve or even roll over.
Transporting the vehicle
!
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
purposes.
XTurn the SmartKey to position 2in the igni-
tion lock.
XShift the 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 transmission to position P.
XTurn the SmartKey in the ignition lock to
position0and remove the SmartKey from
the ignition lock.
XSecure the vehicle.
Tow-starting (emergency engine
starting)
!
Vehicles with automatic transmission
must not be tow-started. You could other-
wise damage the automatic transmission.
You can find information on "Jump-starting" at
(
Ypage 299).
Before tow-starting:
Rthe battery must be connected
Rthe engine must be cold
Rthe exhaust system must have cooled down
When tow-starting, it is important that you
observe the safety instructions (
Ypage 301).
Towing and tow-starting303
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