
Engine
Problem Possible causes/consequences and
M Solutions
;
The yellow engine diag-
nostics warning lamp
lights up while the
engine is running.
There may be a fault, for example:
R in the engine management
R in the fuel injection system
R in the exhaust system
R in the ignition system (for vehicles with petrol engines)
R in the fuel system
The emission limit values may be exceeded and the engin emay
be running in emergency mode.
X Have the vehicle checked as soon as possible at a qualified
specialist workshop. Vehicles with a diesel engine: the fuel tan
khas been run dry
(Y page 182).
X Start the engine three to four times after refuelling.
If the yellow engine diagnostics warning lamp goes out, emer-
gency running mode is cancelled. The vehicle need no tbe
checked. 8
The yellow reserve fuel
warning lamp lights up
while the engine is run-
ning.
The fuel level has dropped into the reserve range.
Operation of the auxiliary heating is deactivated if the fuel level
drops into the reserve range.
X
Refuel at the nearest filling station. ?
The red coolant warn-
ing lamp lights up while
the engine is running
and the coolant tem-
perature gauge is at the
star toft he scale. The temperature sensor for the coolant temperature gauge is
faulty.
The coolant temperature is no longer being monitored. There is a
risk of engine damage if the coolant temperature is too high.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine. Do not continue driving
under any circumstances.
X Secure the vehicle against rolling away (Y page 183).
X Consult a qualified specialist workshop. Indicator and warning lamps in the instrument cluster
305On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions
?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning.
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 mal-
functioning.
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 Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 183).
X Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and top up the coolant, observing the
warning notes (Y page 348).
X If you have to top up the coolant frequently, have the engine
cooling system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X Do not start the engine again until the coolant temperature is
under 120 †. The engine may otherwise be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving in
mountainous terrain and stop-start traffic. ?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning. A warning tone
also sounds.
The coolant temperature has exceeded 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.
Never drive with an overheated engine. Driving when your engine
is overheated can cause some fluids which may have leaked into
the engine compartment to catch fire.
Steam from an overheated engine can cause serious burns, which
can occur just by opening the bonnet.
This poses a risk of injury.
X Observe the additional display messages in the multifunction
display.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 183).306
Indicator and warning lamps in the instrument clusterOn-board computer and displays

Problem Possible causes/consequences and
M Solutions
X
Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and top up the coolant, observing the
warning notes (Y page 348).
X If you have to top up the coolant frequently, have the engine
cooling system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X If the coolant temperature is below 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving in
mountainous terrain and stop-start traffic. Driving systems
Problem Possible causes/consequences and
M Solutions
·
The red distance warn-
ing 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. ·
The red distance warn-
ing lamp lights up while
the vehicle is in motion.
Aw
arning 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 195).
Further information on PRE-SAFE ®
Brake (Y page 76). Indicator and warning lamps in the instrument cluster
307On-board computer and displays Z

Tyres
Problem Possible causes/consequences and
M Solutions
h
The yellow tyre pres-
sure monitor warning
lamp is on. The tyre pressure monitor has detected a loss of pressure in at
leas
tone of the tyres.
G WARNING
With tyre pressures which are too low, there is a ris kofthe fol-
lowing hazards:
R the tyres may burst, especially as the load and vehicle speed
increase.
R the tyres may wear excessively and/or unevenly, which may
greatly impair tyre 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
manoeuvres. Pay attention to the traffic conditions as you do
so.
X Secure the vehicle against rolling away (Y page 183).
X Observe the additional display messages in the multifunction
display.
X If there is a flat tyre, inspect the tyres (Y page 363).
X Check the tyre pressure (Y page 386).
X If necessary, correct the tyre pressure. 308
Indicator and warning lamps in the instrument clusterOn-board computer and displays

The left-hand and right-hand rear seat backr-
ests can be folded down separately to
increase the boot capacity.
Folding the seat backrest forwards
!
Before you fold down the rear seat back-
rest, remove the side head restraints for
the integrated child seat; see the "Side
head restraints for integrated child seat"
section. The side head restraints could oth-
erwise be damaged. i
Vehicles with memory function: when you
fold one or both parts of the rear seat back-
rest forwards, the respective fronts eat
moves forward slightly, when necessary, in
order to avoid contact.
X Vehicles without memory function: if nec-
essary, move the driver's or front-
passenger seat forwards.
X Open the boot.
X Pull right-hand or left-hand rear seat back-
rest release handle :.
The corresponding rear seat backrest is
released.
The head restraints for the seat backrests
in the rear compartment lower. X
Fold rear seat backrest ;forwards.
X Move the driver's or front-passenger seat
back if necessary.
Folding back the seat backrest G
WARNING
Make sure that the rear seat backrest is cor-
rectly engaged. Otherwise, vehicle occupants
could be injured by objects being thrown
around if you:
R brake sharply
R change direction suddenly
R are involved in an accident
If the rear seat backrest is not engaged, this
will be shown in the multifunction display in
the instrument cluster.
! Make sure that the seat belt does not
become trapped when folding the rear seat
backrest back. Otherwise, it could be dam-
aged. 316
Stowage areasStowing and features

X
Vehicles without memory function: if nec-
essary, move the driver's or front-
passenger seat forwards.
X Pull the left-hand or right-hand release han-
dle at the rear in load compartment :or
at the side beside backrests ;.
The corresponding backrest folds for-
wards.
X Pull back the left or right release lever in
the luggage compartment :.
The corresponding backrest folds for-
wards.
X Move the driver's or front-passenger seat
back if necessary.
Folding the rear seat backrest back G
WARNING
Make sure that the rear seat backrest is cor-
rectly engaged. Otherwise, vehicle occupants
could be injured by objects being thrown
around if you:
R brake sharply
R change direction suddenly
R are involved in an accident
If the rear seat backrest is not engaged, this
will be shown in the multifunction display in
the instrument cluster.
! Make sure that the seat belt does not
become trapped when folding the rear seat
backrest back. Otherwise, it could be dam-
aged. X
Move the driver's or front-passenger seat
forward if necessary.
X Fold seat backrest :back until it engages.
X Adjust the head restraints if necessary
(Y page 110).
X Move the driver's or front-passenger seat
back if necessary. Securing
aload
Plastic hooks (Saloon) On vehicles without a through-loading feature
in the rear bench seat, six plastic hooks are
fitted to the boot floor. You can use these to
attach the luggage securing fixture, which is
available as an accessory.
Lashing eyelets General notes
G
WARNING
Distribute the load on the lashing eyelets
evenly.
Otherwise, vehicle occupants could be
injured by objects being thrown around if you:
R brake sharply
R change directio nsuddenly
R are involved in an accident
Please observe the loading guidelines. 318
Stowage areasStowing and featu
res

Useful information
i This Owner's Manual describes all mod-
els, series and optional equipment for your
vehicle that were available at the time of
going to press. National variations are pos-
sible. Note that your vehicle may not be
equipped with all of the functions descri-
bed. This is also the case for systems and
functions relevant to safety.
i Read the information on qualified special-
ist workshops: (Y page 25). Engine compartment
Bonnet
Active bonnet (pedestrian protection) Operating principle
G
WARNING
If you pull the bonnet release lever and then
neglec tto reset the bonnet, it will not lock at
the front when closed. The bonnet can then
open when the vehicle is in motion and
obscure your field of vision. If you pull the
bonnet release lever, you must reset the bon-
net before driving on.
! Do not try to press down the raised bon-
net at the back. Otherwise, the bonnet
could be damaged.
i The active bonnet is only available in cer-
tain countries. It is available for all models,
except for AMG vehicles.
The active bonnet can reduce the risk of injury
to pedestrians in certain accident situations.
Raising the active bonnet increases the clear-
ance to hard components, such as the engine. If active bonnet
:has been triggered, it will
be raised at the back by about 50 mm.
Lids ;will then no longer rest on housings
=.
You can reset a triggered active bonnet your-
self.
Even if the active bonnet has been triggered,
you can still continue driving and have it reset
at a qualified specialist workshop. If you pull
the bonnet release lever, you must reset the
bonnet before driving on.
Resetting G
WARNING
There is a risk of injury if the bonnet is open,
even if the engine is not running.
Some engine components can become very
hot.
To avoid the risk of burns, only touch those
components described in the Owner's Manual
and observe the relevant safety notes. G
WARNING
If the bonnet can still not be engaged properly
or the Lsymbol appears in the multifunc-
tion display, do not continue driving. The bon-
net can then open when the vehicle is in
motion and obscure your field of vision. Con-
sult a qualified specialist workshop. Other-
wise, you may cause an accident and injure
yourself and others. 344
Engine compartmentMaintenance and care

X
Open the bonnet (Y page 345).
X With both hands, lift the bonnet up in the
centre A.The bonnet is open wide enough
when both lids of bonnet lifter ;no longer
move.
If you push the lids back, you will notice a
resistance.
X Release bonnet :.
X Check whether the lids of bonnet lifter ;
are resting on housings =(arrow).
X The lids of bonnet lifter ; are resting
on the housings: close bonnet:
(Y page 346).
or
X The lids of bonnet lifter ; are not rest-
ing on the housings: first lift up bon-
net :on left-hand side ?and then on
right-hand side B. Lift up bonnet :until
the respective lid of bonnet lifter ;no lon-
ger moves.
The lids of bonnet lifter ;must rest on
housings =(arrow).
X Close bonnet :(Ypage 346).
If you cannot close the bonnet :or if the
L symbol appears in the multifunction
display, repeat the steps.
Opening the bonnet G
WARNING
Do not pull the release lever while the vehicle
is in motion. If you do so, the bonnet may open
up and block your view. G
WARNING
Hybrid vehicles: ensure that you read the
"HYBRID" supplement. You could otherwise
fail to recognise dangers. G
WARNING
There is a risk of injury if the bonnet is open,
even if the engine is not running.
Some engine components can become very
hot.
To avoid the risk of burns, only touch those
components described in the Owner's Manual
and observe the relevant safety notes. G
WARNING
The radiator fan between the radiator and the
engine can start automatically, even if the key
has been removed from the ignition lock. For
this reason, you must not reach into the fan
rotation area. You could otherwise be injured.
Vehicles with apetrol engine: The elec-
tronic ignitio nsystem uses high voltage. For
this reason, you mus tnever touch ignition
system components (ignition coil, ignition
cables, spark plug connectors or test socket)
while:
R the engine is running
R the engine is being started
R the ignition is switched on and the engine
is being cranked by hand
You could otherwise suffer an electric shock
and be seriously or even fatally injured.
Vehicles with adiesel engine: The elec-
tronic injection control uses high voltage. For
this reason, you must never touch injection
system components while:
R the engine is running
R the engine is being started
R the ignition is switched on
You could otherwise suffer an electric shock
and be seriously or even fatally injured. Engine compartment
345Maintenance and care Z