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. G
WARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with the skin, eyes or clothing. Do not breathe in any battery gases. Do not lean over the battery. Keep the batteries out of the reach of children. Immediately rinse off battery acid
thoroughly with plenty of clean water and seek medical attention at once. G
WARNING
During charging and jump-starting, explosive gases can escape from the battery. There is a risk of an explosion.
Particularly avoid fire, naked flames, creating sparks and smoking. Ensure there is sufficient
ventilation while charging and jump-starting. Do not lean over a battery. G
WARNING
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.
R Make sure that the positive terminal of a connected battery does not come into contact with
vehicle parts.
R Never place metal objects or tools on a battery.
R It is important that you observe the described order of the battery terminals when connecting
and disconnecting a battery.
R When jump-starting, make sure that the battery poles with identical polarity are connected.
R It is particularly important to observe the described order when connecting and disconnecting
the jump leads.
R Never connect or disconnect the battery terminals while the engine is running. G
WARNING
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.
! Vehicles with a petrol engine:
avoid repeated and lengthy starting attempts. Otherwise,
the non-combusted fuel may damage the catalytic converter.
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 jump-start the vehicle nor charge
the battery. Let the battery thaw first. The service life of a battery that has been thawed may
be reduced. The starting characteristics may be impaired, especially at low temperatures.
Have the thawed battery checked at a qualified specialist workshop. 348
Jump-startingBreakdown assistance
Do not use a rapid charging device to start the vehicle. If your vehicle's battery is discharged,
the engine can be jump-started from another vehicle or from a second battery using jump
leads. Observe the following points:
R The 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.
R Do not start the engine if the battery is frozen. Let the battery thaw first.
R Jump-starting may only be performed using batteries with a nominal voltage of 12 V.
R Only use jump leads that are not damaged and have a sufficient cross-section and insulated
terminal clamps.
R Make sure that the two vehicles do not touch.
Make sure that:
R The jump leads are not damaged.
R Non-insulated parts of the terminal clamps do not come into contact with other metal parts
while the jump leads are connected to the battery.
R The jump leads cannot come into contact with parts which can move when the engine is
running, such as the V-belt pulley or the fan.
X Secure the vehicle by applying the electric parking brake.
X Manual transmission: depress the clutch pedal fully and shift to neutral.
X Automatic transmission: shift the transmission to position P.
X Turn the key to position 0in the ignition lock and remove it.
X Switch off all electrical consumers, e.g. rear window heating, lighting etc.
X Open the bonnet. Position number
Bidentifies the charged battery of the other vehicle or an equivalent jump-
starting device.
X Press together cover :of positive clamp ;and slide it back.
X Connect positive terminal ;on your vehicle to positive terminal =of donor battery B
using the jump lead, beginning with your own battery. Jump-starting
349Breakdown assistance Z
X
Start the engine of the donor vehicle and run it at idling speed.
X Connect negative terminal ?of donor battery Bto earth point Aof your vehicle using the
jump lead, connecting the jump lead to donor battery Bfirst.
X If 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.
X Start the engine.
X Before disconnecting the jump leads, let the engines run for several minutes.
X First, remove the jump leads from earth point Aand negative terminal ?, then from pos-
itive clamp ;and positive terminal =. Begin each time at the contacts on your own vehicle
first.
X Close cover :of positive clamp ;after removing the jump leads.
X Close the bonnet.
X Have the battery checked at a qualified specialist workshop.
i Jump-starting is not considered to be a normal operating condition.
i Jump-starting cables and further information regarding jump starting can be obtained at
any qualified specialist workshop. Towing away and tow-starting
Important safety notes
G
WARNING
Safety relevant functions are restricted or no
longer available if:
R the engine is not running
R the brake system or power steering is mal-
functioning
R there is a malfunction in the voltage supply
or the vehicle's electrical system
When your vehicle is towed away or towed
started, you may require considerably more
effort to steer and brake. There is a risk of an
accident.
In such cases use a rigid towing bar. Before
being towed away or tow started, make sure
the steering moves freely. G
WARNING
If the steering wheel lock is engaged, the vehi- cle can no longer be steered. There is a risk of
an accident.
Always switch on the ignition when towing
with a tow rope or a towing bar. G
WARNING
When towing or tow-starting another vehicle
and its weight is greater than the permissible gross weight of your vehicle, the:
R towing eye may be torn off
R car/trailer combination may swerve or
even overturn
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 identification plate (Y page 396).
! When COLLISION PREVENTION ASSIST
PLUS, DISTRONIC PLUS or the HOLD func- tion is activated, the vehicle brakes auto-
matically in certain situations. To avoid
damage to the vehicle, deactivate these
systems in the following or similar situa-
tions:
R when towing away
R in a car wash 350
Towing away and tow-startingBreakdown assistance
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.
X Vehicles with manual transmission:
depress the clutch pedal fully and engage
neutral.
X Turn the key to position 2in the ignition
lock (Y page 157).
X Vehicles with automatic transmission:
turn the key to position 2in the ignition lock
(Y page 157).
X Shift the transmission to position N.
As soon as the vehicle is loaded: X Prevent the vehicle from rolling away by
applying the electric parking brake.
X Vehicles with manual transmission:
depress the clutch pedal fully and engage
first or reverse gear.
X Vehicles with automatic transmission:
shift the transmission to position P.
X Turn the key to position 0in the ignition
lock and remove it.
X Secure the vehicle.
The towing eyes or trailer tow hitch can be
used to pull the vehicle onto a trailer or trans- porter if you wish to transport it. Notes for 4MATIC vehicles
! Vehicles with 4MATIC must not be towed
with the front or rear axle raised; otherwise, the transmission may be damaged.
Vehicles with 4MATIC may only be either
towed away with both axles on the ground or be loaded up and transported.
If the vehicle has transmission damage or
damage to the front or rear axle, have it trans-
ported 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 348).
Have the vehicle transported on a transporter
or trailer. Tow-starting (emergency engine
starting)
! Do not tow-start vehicles with automatic
transmission. You could otherwise damage the automatic transmission.
i You can find information on "Jump-start-
ing" under (Y page 348).
Before tow-starting, the following conditions
must be fulfilled: R the battery is connected
R the engine has cooled down
R the exhaust system has cooled down
When tow-starting, it is important that you
observe the safety notes (Y page 350)and the
legal requirements in each respective coun-
try.
X Switch on the hazard warning lamps
(Y page 123).
X Fit the towing eye (Y page 352).
X Secure the rigid towing bar or the towing
rope.
X When the vehicle is stationary, depress the
brake pedal and keep it depressed.
X Turn the key to position 2in the ignition
lock (Y page 157).
X Depress the clutch pedal fully, engage sec-
ond gear and continue to keep the clutch
pedal fully depressed.
X Release the brake pedal.
X Tow-start the vehicle. 354
Towing away and tow-startingBreakdo
wn assis tance