Problem
Possible causes/consequences and
0050
0050Solutions 00AC
The red coolant warn-
ing lamp lights up while
the engine is running
and the coolant tem-
perature gauge is at the start of the scale. The temperature sensor for the coolant temperature gage is defec-
tive.
The coolant temperature is no longer being monitored. There is a risk of engine damage if the coolant temperature is too high.
X Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions. Do not continue
driving under any circumstances.
X Secure the vehicle against rolling away (Y page 190).
X Consult a qualified specialist workshop. 336
Warning and indicator lamps in the instrument clusterOn-board computer and displays
Problem
Possible causes/consequences and
0050
0050Solutions 00AC
The red coolant warn-
ing lamp comes on
while the engine is run-
ning.
The coolant level is too low.
! Avoid making long journeys with too little coolant in the engine
cooling system. The engine will otherwise be damaged.
If the coolant level is correct, the airflow to the engine radiator may be blocked or the electric engine radiator fan may be malfunc-
tioning.
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 375).
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 moun-
tainous terrain, and stop-and-go traffic. 00AC
The red coolant warn-
ing lamp comes on
while the engine is run-
ning. A warning tone
also sounds.
The coolant temperature has exceeded 248 ‡ (120 †). The air-
flow 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. Warning and indicator lamps in the instrument cluster
337On-board computer and displays Z
Problem
Possible causes/consequences and
0050
0050Solutions 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 375).
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 moun-
tainous terrain, and stop-and-go traffic. Driving systems
Problem
Possible causes/consequences and
0050 0050Solutions 00BA
The red distance warn-
ing function warning
lamp comes on while
the vehicle is moving. 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 DISTRONIC PLUS (Y page 206).
Further information on PRE‑ SAFE®
Brake (Y page 76).
Further information on the distance warning function (Y page 70).338
Warning and indicator lamps in the instrument clusterOn-board computer and displays
Tires
Problem
Possible causes/consequences and
0050
0050Solutions 0077
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 fol-
lowing 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 389).
X Check the tire pressure (Y page 414).
X If necessary, correct the tire pressure. 0077
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. Warning and indicator lamps in the instrument cluster
339On-board computer and displays Z
006B
Wheel bolts
006C Towing eye
X Lift the cargo compartment floor up
(Y page 349). Flat tire
Preparing the vehicle
Your vehicle may be equipped with: R MOExtended tires (tires with run-flat prop-
erties) (Y page 389)
Vehicle preparation is not necessary on
vehicles with MOExtended tires.
R a TIREFIT kit (Y page 388)
R an emergency spare wheel (only for certain
countries) (Y page 440)
Information on changing/mounting a wheel
(Y page 429).
X Stop the vehicle on solid, non-slippery and
level ground, as far away as possible from
traffic.
X Switch on the hazard warning lamps.
X Secure the vehicle against rolling away
(Y page 190).
X If possible, bring the front wheels into the
straight-ahead position.
X Vehicles with the ON&OFFROAD pack-
age: make sure that highway level is selec-
ted (Y page 214).
X Vehicles with the ON&OFFROAD pack-
age: make sure that highway level is selec-
ted (Y page 214).
X Switch off the engine.
X Vehicles without KEYLESS-GO: remove
the SmartKey from the ignition lock.
X Vehicles with KEYLESS-GO: open the
driver's door.
The on-board electronics now have status
0. This is the same as the SmartKey having
been removed. X
Vehicles with KEYLESS-GO: remove the
Start/Stop button from the ignition lock
(Y page 167).
X All occupants must get out of the vehicle.
Make sure that they are not endangered as
they do so.
X Make sure that no one is near the danger
area while a wheel is being changed. Any-
one who is not directly assisting in the
wheel change should, for example, stand
behind the barrier.
X Get out of the vehicle. Pay attention to traf-
fic conditions when doing so.
X Close the driver's door.
X Unload heavy luggage.
i Only operate the tire inflation compressor
using a 12 V socket, even if the ignition is
turned off (Y page 354).
An emergency cut-out ensures that the on- board voltage does not drop too low. If the on-board voltage is too low, the power to
the sockets is automatically cut. This
ensures that there is sufficient power to
start the engine. MOExtended tires (tires with run-flat
properties)
General notes With MOExtended tires (tires with run flat
characteristics), you can continue to drive
your vehicle even if there is a total loss of
pressure in one or more tires. The affected
tire must not show any clearly visible damage.
You can recognize MOExtended tires by the
MOExtended marking which appears on the
sidewall of the tire. You will find this marking
next to the tire size designation, the load-
bearing capacity and the speed index
(Y page 423).
MOExtended tires may only be used in con-
junction with an active tire pressure loss
warning system or with an active tire pressure
monitor. Flat tire
389Breakdown assistance
X
Remove the towing eye from the vehicle
tool kit (Y page 388).
X To open the cover at the front: press the
mark on cover 0043inwards in the direction
of the arrow.
X To open the cover at the rear: insert a
flat, blunt object into the cutout and lever
cover 0044out of the bumper.
X Take cover 0043or0044 off the opening.
X Screw in and tighten the towing eye clock-
wise to the stop.
Removing the towing eye X
Unscrew and remove the towing eye.
X Attach cover 0043or0044 to the bumper and
press until it engages.
X Place the towing eye in the vehicle tool kit. 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.
Only possible for vehicles without
4MATIC.
X Switch on the hazard warning lamps
(Y page 132).
X Bring the front wheels into the straight-
ahead position.
X Turn the SmartKey to position 0in the igni-
tion lock and remove the SmartKey from
the ignition lock.
X When leaving the vehicle, take the Smart-
Key or the KEYLESS-GO key with you.
When towing your vehicle with the rear axle
raised, it is important that you observe the
safety instructions (Y page 399). Towing a vehicle with both axles on
the ground
It is important that you observe the safety
instructions when towing away your vehicle
(Y page 399).
The automatic transmission automatically
shifts to position Pwhen you open the driver's
or front-passenger door or when you remove the SmartKey from the ignition lock.
In order to ensure that the automatic trans-
mission stays in position Nwhen towing the
vehicle, you must observe the following
points:
X Make sure that the vehicle is stationary and
the SmartKey in the ignition lock is in posi-
tion 0.
X Turn the SmartKey to position 2in the igni-
tion lock.
On vehicles with KEYLESS-GO, use the
SmartKey instead of the Start/Stop button
(Y page 167).
X Depress and hold the brake pedal.
X Shift the automatic transmission to posi-
tion N.
X Release the brake pedal.
X Release the electric parking brake.
X Leave the SmartKey in position 2in the
ignition lock.
X Switch on the hazard warning lamps
(Y page 132).
i In order to signal a change of direction
when towing the vehicle with the hazard
warning lamps switched on, use the com-
bination switch as usual. In this case, only
the indicator lamps for the direction of
travel flash. After resetting the combina-
tion switch, the hazard warning lamp starts
flashing again. Transporting the vehicle
! You may only secure the vehicle by the
wheels, not by parts of the vehicle such as Towing and tow-starting
401Breakdown assistance Z
Example: current tire pressure display
For information on the message display, refer to the "Checking the tire pressure electroni-
cally" section (Y page 416).
Important safety notes G
WARNING
Each tire, including the spare (if provided),
should be checked at least once a month
when cold and inflated to the pressure rec-
ommended by the vehicle manufacturer on
the Tire and Loading Information placard on
the driver's door B-pillar or the tire pressure
label on the inside of the fuel filler flap. If your vehicle has tires of a different size than the
size indicated on the Tire and Loading Infor-
mation placard or the tire pressure label, you should determine the proper tire pressure for
those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitoring system (TPMS) that illuminates a low tire pres-
sure telltale when one or more of your tires
are significantly underinflated. Accordingly,
when the low tire pressure telltale illuminates,
you should stop and check your tires as soon
as possible, and inflate them to the proper
pressure. Driving on a significantly underin-
flated tire causes the tire to overheat and can lead to tire failure. Underinflation also
reduces fuel efficiency and tire tread life, andmay affect the vehicle's handling and stop-
ping ability.
Please note that the TPMS is not a substitute
for proper tire maintenance, and it is the driv-
er's responsibility to maintain correct tire
pressure, even if underinflation has not
reached the level to trigger illumination of the
TPMS low tire pressure telltale. USA only:
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate if the
system is not operating properly. The TPMS
malfunction indicator is combined with the
low tire pressure telltale. When the system
detects a malfunction, the warning lamp will
flash for approximately a minute and then
remain continuously illuminated. This
sequence will be repeated every time the vehi- cle is started as long as the malfunction
exists.
When the malfunction indicator is illuminated,
the system may not be able to detect or signal low tire pressure as intended. TPMS malfunc-tions may occur for a variety of reasons,
including the mounting of incompatible
replacement or alternate tires or wheels on
the vehicle that prevent the TPMS from func-
tioning properly. Always check the TPMS mal-
function telltale after replacing one or more
tires or wheels on your vehicle to ensure that the replacement or alternate tires and wheels
allow the TPMS to continue to function prop-
erly.
It is the driver's responsibility to set the tire
pressure to that recommended for cold tires
which is suitable for the operating situation
(Y page 410). Note that the correct tire pres-
sure for the current operating situation must
first be taught-in to the tire pressure monitor. If there is a substantial loss of pressure, the
warning threshold for the warning message isaligned to the reference values taught-in.
Restart the tire pressure monitor after adjust-
ing the pressure of the cold tires
(Y page 417). The current pressures are
saved as new reference values. As a result, a
warning message will appear if the tire pres-
sure drops significantly.
The tire pressure monitor does not warn you
of an incorrectly set tire pressure. Observe
the notes on the recommended tire pressure
(Y page 410).
The tire pressure monitor is not able to warn
you of a sudden loss of pressure, e.g. if the Tire pressure
415Wheels and tires Z