Page 290 of 338

The jump-starting connection point is in the
engine compartment (Y page 290).
X Open the hood.
X Connect the battery charger to the positive
terminal and ground point in the same
order as when connecting the donor bat-
tery in the jump-starting procedure
(Y page 290).
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. The service life of a
thawed-out battery may be shorter. The start-
ing characteristics can be impaired, particu-
larly at low temperatures. Have the thawed-
out battery checked at a qualified specialist
workshop.
Only charge the installed battery with a bat-
tery charger which has been tested and
approved by Mercedes-Benz. 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 informa-
tion and availability. Read the battery charg-
er's operating instructions before charging
the battery. High-voltage battery – important
safety notes
G
DANGER
The vehicle's high voltage electrical system is under high voltage. If you modify components
in the vehicle's high-voltage electrical system or touch damaged components, you may be
electrocuted. The components in the vehi-
cle's high-voltage electrical system may be
damaged in an accident, although the damage
is not visible. There is a risk of fatal injury.
Following an accident, do not touch any high- voltage components and never modify the
vehicle's high-voltage electrical system. Have the vehicle towed away after an accident and
the vehicle's high-voltage electrical system
checked by a qualified specialist workshop. G
WARNING
In the event of a vehicle fire, the internal pres- sure of the high-voltage battery can exceed a
critical value. In this case flammable gas
escapes through a ventilation valve on the
underbody. The gas can ignite. There is a risk of injury.
Leave the danger zone immediately. Secure
the danger area at a suitable distance, whilst
observing legal requirements.
The vehicle's high voltage electrical system is under high voltage.
R Do not handle high-voltage components or
the orange cables of the vehicle's high-volt-age electrical system.
R Do not touch high-voltage components or
the orange cables of the high-voltage elec-
trical system when a vehicle has been
involved in a crash.
R Do not touch any damaged components or
the damaged orange cables of the vehicle's
high-voltage electrical system.
R Do not remove the covers of the high-volt-
age electrical system components that are
marked with a warning sticker.
Do not leave the vehicle parked for longer
than 14 days with a high-voltage battery con- dition of charge below 20%.
You can check the condition of charge in the
charge level display (Y page 184).
If you park the vehicle and leave it stationary for longer periods, connect it to a power sup-
ply.
If you leave the vehicle parked for longer than
four weeks, the battery may be damaged by
exhaustive discharging. 288
BatteriesRoadside Assistance
Page 292 of 338

Jump-starting
For the jump-starting procedure, use only the jump-starting connection point, consisting of a positive terminal and a ground point, in the engine compartment. G
WARNING
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. G
WARNING
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. 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 jumper cables.
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.
! Avoid repeated and lengthy starting attempts.
Do not use a rapid-charging device to start the engine.
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. The service life of a thawed-out battery may be shorter. Have the thawed-out
battery checked at a qualified specialist workshop.
If the 12 V battery is discharged, or after the vehicle has been jump-started, the Without
Without
changing gear, consult workshop
changing gear, consult workshop message appears. There is a malfunction in the on-
board voltage. Visit a qualified specialist workshop immediately.290
Jump-startingRoadside Assistance
Page 303 of 338

other obstacles. If it is necessary to drive over
curbs, speed humps or similar elevations, try to do so slowly and at an obtuse angle. Oth-
erwise, the tires, particularly the sidewalls,
may be damaged. Regular checking of wheels and tires
G
WARNING
Damaged tires can cause tire inflation pres-
sure loss. As a result, you could lose control of your vehicle. There is a risk of accident.
Check the tires regularly for signs of damage
and replace any damaged tires immediately.
Regularly check the wheels and tires of your
vehicle for damage at least once a month, as well as after driving off-road or on rough
roads. Damaged wheels can cause a loss of
tire pressure. Pay particular attention to dam-
age such as:
R cuts in the tires
R punctures
R tears in the tires
R bulges on tires
R deformation or severe corrosion on wheels
Regularly check the tire tread depth and the
condition of the tread across the whole width of the tire (Y page 301). If necessary, turn the
front wheels to full lock in order to inspect the
inner side of the tire surface.
All wheels must have a valve cap to protect
the valve against dirt and moisture. Do not
mount anything onto the valve other than the standard valve cap or other valve caps
approved by Mercedes-Benz for your vehicle.
Do not use any other valve caps or systems,
e.g. tire pressure monitoring systems.
Regularly check the pressure of all the tires
particularly prior to long trips. Adjust the tire pressure as necessary (Y page 303).The service life of tires depends, among other
things, on the following factors:
R Driving style
R Tire pressure
R Distance covered Notes on tire tread
G
WARNING
Insufficient tire tread will reduce tire traction.
The tire is no longer able to dissipate water.
This means that on wet road surfaces, the risk of hydroplaning increases, in particular where speed is not adapted to suit the driving con-
ditions. There is a risk of accident.
If the tire pressure is too high or too low, tires
may exhibit different levels of wear at differ-
ent locations on the tire tread. Thus, you
should regularly check the tread depth and
the condition of the tread across the entire
width of all tires.
Minimum tire tread depth for:
R Summer tires: âin (3 mm)
R M+S tires: ãin (4 mm)
For safety reasons, replace the tires before
the legally prescribed limit for the minimum
tire tread depth is reached. Marking
:shows where the bar indicator
(arrow) for tread wear is integrated into the
tire tread.
Treadwear indicators (TWI) are required by
law. Six indicators are positioned on the tire
tread. They are visible once a tread depth of Operation
301Wheels and tires Z