Warning/
indicator
lamp 0051
0051 Signal type
Possible causes/consequences and 0050
0050 Solutions 00AC
0051
The red coolant warning lamp comes on while the engine is running.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator may be blocked
or the electric engine radiator fan may be malfunctioning.
The coolant is too hot and the engine is no longer being cooled sufficiently.
X Observe the additional display messages in the multifunction display.
X Pull over and stop the vehicle safely and switch off the engine, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 190).
X Leave the vehicle and keep a safe distance from the vehicle until the engine
has cooled down.
X Check the coolant level and add coolant, observing the warning notes
(Y page 351).
X If you need to add coolant more often than usual, have the engine coolant
system checked.
X Make sure that the air supply to the engine radiator is not blocked, e.g. by
snow, slush or ice.
X Do not start the engine again until the coolant temperature is below
248 ‡ (120 †). Otherwise, the engine could be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in mountainous
terrain, and stop-and-go traffic. 00AC
0051
The red coolant warning lamp comes on while the engine is running. A
warning tone also sounds.
The coolant temperature has exceeded 248 ‡ (120 †). The airflow to the
engine radiator may be blocked or the coolant level may be too low.
G WARNING
The engine is not being cooled sufficiently and may be damaged.
Do not drive when your engine is overheated. This can cause some fluids which
may have leaked into the engine compartment to catch fire.
Steam from the overheated engine can also cause serious burns which can
occur just by opening the hood.
There is a risk of injury.
X Observe the additional display messages in the multifunction display.
X Pull over and stop the vehicle safely and switch off the engine, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 190).310
Warning and indicator lamps in the instrument clusterOn-board computer and displays
Warning/
indicator
lamp 0051 0051
Signal type
Possible causes/consequences and 0050
0050Solutions X
Leave the vehicle and keep a safe distance from the vehicle until the engine
has cooled down.
X Check the coolant level and add coolant, observing the warning notes
(Y page 351).
X If you need to add coolant more often than usual, have the engine coolant
system checked.
X Make sure that the air supply to the engine radiator is not blocked, e.g. by
snow, slush or ice.
X At coolant temperatures below 248 ‡(120 †), drive to the nearest qualified
specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in mountainous
terrain, and stop-and-go traffic. Driving systems
Warning/
indicator
lamp 0051 0051
Signal type
Possible causes/consequences and 0050
0050Solutions 00BA
0051
The red distance warning lamp lights up while the vehicle is in motion.
The distance to the vehicle in front is too small for the speed selected.
X Increase the distance. 00BA
0051
The red distance warning lamp lights up while the vehicle is in motion. A
warning tone also sounds.
You are approaching a vehicle or a stationary obstacle in your line of travel at
too high a speed.
X Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to brake or take
evasive action.
Further information on PRE-SAFE ®
Brake (Y page 78).
For further information on the distance warning function of COLLISION
PREVENTION ASSIST: (Y page 73). Warning and indicator lamps in the instrument cluster
311On-board computer and displays Z
Tires
Warning/
indicator
lamp 0051 0051
Signal type
Possible causes/consequences and 0050
0050Solutions 0077
0051
The yellow tire pressure monitor warning lamp (pressure loss/malfunction)
is lit.
The tire pressure monitor has detected a loss of pressure in at least one of
the tires.
G WARNING
With tire pressures which are too low, there is a risk of the following hazards:
R they may burst, especially as the load and vehicle speed increase.
R they may wear excessively and/or unevenly, which may greatly impair tire
traction.
R the driving characteristics, as well as steering and braking, may be greatly
impaired.
There is a risk of an accident.
X Stop the vehicle without making any sudden steering or braking maneuvers.
Pay attention to the traffic conditions as you do so.
X Secure the vehicle against rolling away (Y page 190).
X Observe the additional display messages in the multifunction display.
X Check the tires and, if necessary, follow the instructions for a flat tire
(Y page 365).
X Check the tire pressure (Y page 391).
X If necessary, correct the tire pressure. 0077
0051
The yellow tire pressure monitor warning lamp (pressure loss/malfunction)
flashes for approximately one minute and then remains lit.
The tire pressure monitor is faulty.
G WARNING
The system is possibly unable to recognize or register low tire pressure.
There is a risk of an accident.
X Observe the additional display messages in the multifunction display.
X Visit a qualified specialist workshop. 312
Warning and indicator lamps in the instrument clusterOn-board computer and displays
Vehicle
Warning/
indicator
lamp 0051 0051
Signal type
Possible causes/consequences and 0050
0050Solutions 00CC
0051
The red power steering warning lamp is lit while the engine is running.
The power steering is malfunctioning.
A warning tone also sounds.
G WARNING
You will need to use more force to steer.
There is a risk of an accident.
X Check whether you are able to apply the extra force required.
X If you are able to steer safely: carefully drive on to a qualified specialist
workshop.
X If you are unable to steer safely: do not drive on. Contact the nearest
qualified specialist workshop. Warning and indicator lamps in the instrument cluster
313On-board computer and displays Z
Additional service products
Checking coolant level G
WARNING
Certain components in the engine
compartment, such as the engine, radiator
and parts of the exhaust system, can become
very hot. Working in the engine compartment
poses a risk of injury.
Where possible, let the engine cool down and
touch only the components described in the
following. G
WARNING
The engine cooling system is pressurized,
particularly when the engine is warm. When
opening the cap, you could be scalded by hot
coolant spraying out. There is a risk of injury.
Let the engine cool down before opening the
cap. Wear eye and hand protection when
opening the cap. Open the cap slowly half a
turn to allow pressure to escape. X
Park the vehicle on a level surface.
Only check the coolant level when the
vehicle is on a level surface and the engine
has cooled down.
X Turn the SmartKey to position 2in the
ignition lock (Y page 171).
or
X Press Start/Stop button twice
(Y page 171). X
Check the coolant temperature display in
the instrument cluster.
The coolant temperature must be below
158 ‡ (70 †).
X Turn the SmartKey to position
0(Y page 171) in the ignition lock.
or
X Remove Start/Stop button from ignition
lock (Y page 171).
X Slowly turn cap 0043half a turn counter-
clockwise to allow excess pressure to
escape.
X Turn cap 0043further counter-clockwise and
remove it.
If the coolant is at the level of marker bar
0087 in the filler neck when cold, there is
enough coolant in coolant expansion
tank 0044.
If the coolant level is approximately 0.6 in
(1.5 cm) above marker bar 0087in the filler
neck when warm, there is enough coolant
in expansion tank 0044.
X If necessary, add coolant that has been
tested and approved by Mercedes-Benz.
X Replace cap 0043and turn it clockwise as far
as it will go.
For further information on coolant, see
(Y page 426).
Adding washer fluid to the windshield
washer system G
WARNING
Certain components in the engine
compartment, such as the engine, radiator
and parts of the exhaust system, can become
very hot. Working in the engine compartment
poses a risk of injury.
Where possible, let the engine cool down and
touch only the components described in the
following. G
WARNING
Windshield washer concentrate is highly
flammable. If it comes into contact with hot Engine compartment
351Maintenance and care
Z
Do not switch off the tire inflation
compressor during this phase.
X Allow the tire inflation compressor to run
for five minutes. The tire should then have
attained a pressure of at least 180 kPa
(1.8 bar/26 psi).
If a pressure of 180 kP a(1 .8 ba r/26 psi) has
been attained after five minutes, see "Tire
pressure reached" (Y page 368).
If a tire pressure of 180 kPa (1.8 ba r/26 psi)
has not been attained after five minutes, see
"Tire pressure not reached" (Y page 368).
i If tire sealant leaks out, allow it to dry. It
can then be removed like a layer of film.
If your clothes are soiled with tire sealant,
have them cleaned with perchloroethylene
at a dry cleaner as soon as possible.
Tire pressure not reached If a pressure of 180 kPa
(1.8 ba r/26 psi) has
not been attained after five minutes:
X Switch off the tire inflation compressor.
X Unscrew the filler hose from the valve of
the faulty tire.
X Very slowly drive forwards or reverse
approximately 30 ft (10 m).
X Pump up the tire again.
After a maximum of five minutes the tire
pressure must be at least 180 kPa (1.8 bar/
26 psi). G
WARNING
If the required tire pressure is not reached
after the specified time, the tire is too badly
damaged. The tire sealant cannot repair the
tire in this instance. Damaged tires and a tire
pressure that is too low can significantly
impair the vehicle's braking and driving
characteristics. There is a risk of accident.
Do not continue driving. Contact a qualified
specialist workshop. Tire pressure reached G
WARNING
A tire temporarily sealed with tire sealant
impairs the driving characteristics and is not
suitable for higher speeds. There is a risk of
accident.
You should therefore adapt your driving style
accordingly and drive carefully. Do not exceed
the specified maximum speed with a tire that
has been repaired using tire sealant.
The maximum speed for a tire sealed with tire
sealant is 50 mph (80 km/h). The upper part
of the TIREFIT sticker must be affixed to the
instrument cluster in the driver's field of
vision.
! Residue from the tire sealant may come
out of the filler hose after use. This could
cause stains.
Therefore, place the filler hose in the plastic
bag which contained the TIREFIT kit. H
Environmental note
Have the used tire sealant bottle disposed of
professionally, e.g. at a qualified specialist
workshop.
If a tire pressure of 180 kPa (1.8 ba r/26 psi)
has been attained after five minutes:
X Switch off the tire inflation compressor.
X Unscrew the filler hose from the valve of
the faulty tire.
X Stow the tire sealant bottle and the tire
inflation compressor.
X Pull away immediately.
X Stop after driving for approximately ten
minutes and check the tire pressure with
the tire inflation compressor.
The tire pressure must now be at least
130 kPa (1.3 bar/19 psi). G
WARNING
If the required tire pressure is not reached
after driving for a short period, the tire is too
badly damaged. The tire sealant cannot repair 368
Flat tireBreakdown assistance
G
WARNING
Electrostatic build-up can lead to the creation
of sparks, which could ignite the highly
explosive 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:
R by wearing clothing made from synthetic
fibers
R due to friction between clothing and seats
R if you push or pull the battery across the
carpet or other synthetic materials
R if you wipe the battery with a cloth 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
Battery acid is caustic. There is a risk of injury.
Avoid contact with the skin, eyes or clothing.
Do not inhale any battery gases. Do not lean
over the battery. Keep children away from
batteries. Wash battery acid immediately with
water and seek medical attention. H
Environmental note Batteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separately
and recycled to protect the
environment.
Dispose of batteries in an
environmentally friendly
manner. Take discharged
batteries to a qualified
specialist workshop or a
special collection point for
used batteries.
! Have the battery checked regularly at a
qualified specialist workshop.
Observe the service intervals in the
Maintenance Booklet or contact a qualified
specialist workshop for more information.
! You should have all work involving the
battery carried out at a qualified specialist
workshop. In the exceptional case that it is
necessary for you to disconnect the battery
yourself, make sure that:
R secure the vehicle to prevent it from
rolling away.
R you switch off the engine and remove the
SmartKey. Make sure the ignition is
switched off. Check that all the indicator
lamps in the instrument cluster are off.
Otherwise, electronic components, such
as the alternator, may be damaged.
R you first remove the negative terminal
clamp and then the positive terminal
clamp. Never swap the terminal clamps. 370
Battery (vehicle)Breakdown assistance
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.
! 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 373).
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
battery in the jump-starting procedure
(Y page 373).
Never charge a battery still installed in the
vehicle unless a battery charger unit
approved by Mercedes-Benz is being used. An
accessory battery charge unit specially
adapted for Mercedes-Benz vehicles and
tested and approved by Mercedes-Benz is
available. 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.
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 jump-start the vehicle nor
charge the battery. 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. 372
Battery (vehicle)Breakdown assistance