air condition MERCEDES-BENZ C-CLASS SALOON 2011 Owner's Manual

Engine (12-button multifunction steering wheel)
Display messages Possible causes/consequences and
M Solutions
+
Top
up coolant See
Owner's Manual The coolant level is too low.
X
Top up the coolant, observing the warning notes when doing so
(Y page 324).
X If the coolant needs topping up more often than usual, have the
engine coolant system checked at a qualified specialist work-
shop. ?
Coolant Stop vehi‐
cle Switch engine
off The coolant is too hot.
Aw
arning tone also sounds.
X Stop the vehicle immediately, paying attentio ntoroad and traf-
fic conditions, and switch off the engine.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X Wait until the display message disappears before restarting the
engine. Otherwise, there is a risk of engine damage.
X Pay attention to the coolant temperature display.
X If the temperature increases again, visit a qualified specialist
workshop immediately. The poly-V-belt may have torn.
X
Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Open the bonnet.
X Check whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not continue driving. The engine could otherwise overheat.
X Consult a qualified specialist workshop.
If the poly-V-belt is OK:
X Wait until the display message disappears before restarting the
engine. Otherwise, there is a risk of engine damage.
X Pay attention to the coolant temperature display.
X Visit a qualified specialist workshop. ? The fan motor is faulty.
X
If the coolant temperature is less than 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 on
mountain roads and stop-start traffic. 270
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
# The battery is no
tbeing charged.
Aw arning tone also sounds.
Possible causes:
R faulty alternator
R torn poly-V-belt
R a malfunction in the electronics
X Stop the vehicle immediately, paying attentio ntoroad and traf-
fic conditions, and switch off the engine.
X Open the bonnet.
X Check whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not continue driving. The engine could otherwise overheat.
X Consult a qualified specialist workshop.
If the poly-V-belt is OK:
X Visit a qualified specialist workshop. 4
Check eng. oil
level when next
refuelling The oil level has dropped to the minimum level.
Aw
arning tone also sounds.
X Chec kthe oil level, at the latest when next refuelling
(Y page 323).
X If necessary, top up the engine oil (Y page 324).
X Have the engine checked at a qualified specialist workshop if
the engine oil needs topping up more often than usual. 8
Reserve fuel level The fuel level has dropped into the reserve range.
Operation of the auxiliary heating is deactivated when the fuel level
drops into the reserve range.
X
Refuel at the nearest filling station. C There is only a very small amount of fuel in the fuel tank.
The auxiliary heating cannot be operated.
X
Refuel at the nearest filling station without fail. ¸
Replace
air cleaner Vehicles with a diesel engine: the engine air filter is dirty and must
be replaced.
X
Visit a qualified specialist workshop. !
Clean
the fuel fil‐
ter Vehicles with a diesel engine: there is water in the fuel filter. The
water must be drained off.
X
Visit a qualified specialist workshop. Display messages
271On-board computer and displays Z

Driving systems (12-button multifunction steering wheel)
Display messages Possible causes/consequences and
M Solutions
À
Attention Assist:
Drowsiness detec‐
ted Based on specific criteria, ATTENTION ASSIST has determined that
the driver is tired or paying less attention
.Awarning tone also
sounds.
X If necessary, take a break.
During long journeys, take regular breaks in good time so you get
enough rest. À
Attention Assist
inoperative ATTENTION ASSIST has failed.
X
Visi taqualified specialist workshop. Speed Limit Assist
currently unavail‐
able See Owner's
Manual Speed Limit Assist is deactivated and temporarily inoperative.
Possible causes:
R
the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
If the display message does not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Apply the parking brake.
X Clean the windscreen.
If the system detects that the camera is fully operational, the dis-
play message disappears.
Speed Limit Assist is operational again. Speed Limit Assist:
Unavailable in
this country Speed Limit Assist is only available in certain countries.
X
Drive on.
Speed Limit Assist is available again when you drive in a country
in which its use is approved. Speed Limit Assist
inoperative Speed Limit Assist is faulty.
X
Visit a qualified specialist workshop. HOLD
Off The HOLD function is deactivated. The vehicle is skidding.
Aw
arning tone also sounds.
X Reactivate the HOLD function later (Y page 193). Display messages
273On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
Lane Keeping
Assist currently
unavailable See
Owner's Man‐
ual orActive Lane
Keeping Assist cur‐
rently unavailable
See Owner's Manual Lane Keeping Assis
torActive Lane Keeping Assist is deactivated
and temporarily inoperative .Possible causes:
R the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
R there are no lane markings for a longer period.
R the lane markings are worn, dark or covered, e.g. by dirt or snow.
If the display message does not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Apply the parking brake.
X Clean the windscreen.
If the system detects that the camera is fully operational, the dis-
play message disappears.
Lane Keeping Assist or Active Lane Keeping Assist is operational
again. Lane Keeping
Assist inopera‐
tive orActive Lane
Keeping Assist
inoperative Lane Keeping Assist or Active Lane Keeping Assist is faulty.
X
Visit a qualified specialist workshop. Display messages
275On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
Blind Spot Assist
currently unavail‐
able See Owner's
Manual orActive
Blind Spot Assist
currently unavail‐
able See Owner's
Manual Blind Spot Assis
torActive Blind Spot Assist is temporarily inop-
erative .Possible causes:
R you have established the electrical connection between the
trailer and your vehicle.
R the sensors are dirty.
R function is impaired due to heavy rain or snow.
R the radar sensor system is outside the operating temperature
range.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation.
The yellow 9indicator lamps also light up in the exterior mir-
rors.
X When towing a trailer, confirm the display message with a.
If you are driving without a trailer and the display message does
not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Apply the parking brake.
X Clean the sensors (Y page 330).
X Restart the engine.
If the system detects that the sensors are fully operational, the
display message disappears.
Blind Spot Assist or Active Blind Spot Assist is operational again. Blind Spot Assist
inopera‐
tive orActive Blind
Spot Assist inoper‐
ative Blind Spot Assist or Active Blind Spot Assist is faulty.
The yellow
9indicator lamps also light up in the exterior mir-
rors.
X Visit a qualified specialist workshop. Parking Guidance
inoperative Parking Guidance is malfunctioning (Y
page 199).
X Restart the engine.
If the display message continues to be displayed:
X Visit a qualified specialist workshop. 276
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
DISTRONIC PLUS
currently unavail‐
able See Owner's
Manual DISTRONIC is deactivated and temporarily inoperative. Possible
causes:
R
the DISTRONIC PLUS cover in the radiator grille is dirty.
R function is impaired due to heavy rain or snow.
R the sensors in the bumpers are dirty.
R the rada rsensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
Aw arning tone also sounds.
If the display message does no tdisappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Clean the DISTRONIC PLUS cover in the radiator grille
(Y page 330).
X Clean the bumpers (Y page 330).
X Restar tthe engine.
If the system detects that the sensors are fully operational, the
display message disappears.
DISTRONIC is operational again. DISTRONIC PLUS
inoperative DISTRONIC PLUS is faulty. BAS PLUS and PRE-SAFE
®
Brake may
also have failed.
Aw arning tone also sounds.
X Visi taqualified specialist workshop. DISTRONIC PLUS
suspended You have depressed the accelerator pedal. DISTRONIC PLUS is no
longer controlling the speed of the vehicle.
X
Take your foot off the accelerator pedal. DISTRONIC PLUS
--- km/h An activation condition for DISTRONIC PLUS is not fulfilled.
X
Check the activation conditions for DISTRONIC PLUS
(Y page 183). DISTRONIC PLUS and
SPEEDTRONIC
inoperative DISTRONIC PLUS and SPEEDTRONIC are faulty. A warning tone
also sounds.
X
Visit a qualified specialist workshop. 278
Display messagesOn-board computer and displays

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 Let the engine and coolant cool down.
X Check the coolant level and top up the coolant (Y page 324).
Observe the warning notes as you do so.
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 less than 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 on
mountain roads 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.
The engine is not being cooled sufficiently and may be damaged.
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 Let the engine and coolant cool down.
X Check the coolant level and top up the coolant (Y page 324).
Observe the warning notes as you do so.
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 less than 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 on
mountain roads and stop-start traffic. Warning and indicator lamps in the instrument cluster
299On-board computer and displays Z

X
Tighten the wheel bolts evenly in a cross-
wise pattern in the sequence indicated
(: toA ). The tightening torque must be
130 Nm. G
WARNING
Have the tightening torque checked immedi-
ately after a wheel is changed. The wheels
could work loose if they are not tightened to
a torque of 130 Nm.
X Turn the jack back to its initial position and
store it together with the rest of the tyre-
change tool kit in the boot/luggage com-
partment.
X Transport the faulty wheel in the boot/lug-
gage compartment.
or
X Depending on the size of the wheel, you
may also be able to secure the faulty wheel
in the spare wheel well. In this case, you
will have to remove the stowage well casing
from the spare wheel well and stow it
securely in the boot/luggage compart-
ment.
i When you are driving with the collapsible
emergency spare wheel fitted, the tyre
pressure loss warning system or the tyre
pressure monitor cannot function reliably.
Only restart the tyre pressure loss warning
system/tyre pressure monitor when the
defective wheel has been replaced with a
new wheel.
Vehicles with tyre pressure monitor: all fit-
ted wheels must be equipped with func- tioning sensors. The defective wheel
should no longer be in the vehicle. MOExtended tyres (tyres with run-flat
characteristics)
MOExtended tyres (tyres with run-flat char-
acteristics) allow you to continue driving the
vehicle even when one or more tyres lose all
air pressure.
MOExtended tyres may only be used in con-
junction with the activated tyre pressure loss
warning system or with the tyre pressure
monitor.
The maximum permissible distance which
can be driven in run-flat mode depends on the
load in the vehicle. It is 80 km if the vehicle
is partially laden and 30 km if fully laden.
The maximum permissible distance which
can be driven in run-flat mode is counted from
the moment the tyre pressure loss warning
appears in the multifunction display.
You must not exceed a maximum speed of
80 km/h. G
WARNING
The handling characteristics of your vehicle
deteriorate in run-flat mode, for example:
R when cornering
R when braking
R when accelerating rapidly
Adapt your driving style accordingly and avoid
sudden changes in direction and sudden
acceleration, as well as driving over obstacles
(i.e. kerbs, potholes), and driving off-road.
This is particularly the case when the vehicle
is heavily laden.
The maximum permissible distance that can
be driven in run-flat mode depends to a large
exten tonthe loads placed on the vehicle. It
can be shorter due to high speeds, a heavy
load, sudden changes in direction, the road
surface condition, outside temperature, etc.,
or further if you drive carefully and conserva-
tively. Flat tyre
345Breakdown assistance
Z

Useful information
i This Owner's Manual describes all models
and all standard and optional equipment
available to your vehicle at the time of pub-
lication of the Owner's Manual. Country-
specific deviations are possible. Please
note that your vehicle may not be equipped
with all features described. This also
applies to safety-relevan tsystems and
functions.
i Please read the information on qualified
specialist workshops (Y page 28).Important safety notes
G
WARNING
Tyres, wheels or accessories which have not
been approved by Mercedes-Ben zfor your
vehicle or are not used as they should be, can
impair driving safety. As a result, you could
cause an accident .Before purchasing and
using them, enquire about their suitability,
legal stipulations and factory recommenda-
tions at a Mercedes-Benz Service Centre.
Modification work on the brake system and
wheels is not permitted, nor is the use of
spacer plates or brake dust shields. This inva-
lidates the General Operating Permit for the
vehicle.
i Further information about tyres and
wheels can be obtained from any
Mercedes-Benz Service Centre. Operation
Notes on driving
R While driving, pay attention to vibrations,
noises and unusual handling characteris-
tics, e.g. pulling to one side. This may indi-
cate that the wheels or tyres are damaged.
If you suspect that a tyre is defective,
reduce your speed immediately. Stop the vehicle as soon as possible to chec
kthe
wheels and tyres for damage. Hidden tyre
damage could also be causing the unusual
handling characteristics. If you find no
signs of damage, have the wheels and tyres
examined at a qualified specialist work-
shop, e.g. a Mercedes-Ben zService
Centre.
R When parking your vehicle, make sure that
the tyres do not get deformed by the kerb
or other obstacles. If it is necessary to drive
over kerbs, speed humps or similar eleva-
tions, try to do so slowly and at an obtuse
angle. Otherwise, the tyres, particularly the
sidewalls, can get damaged. Notes on regularly inspecting wheels
and tyres
R Regularly chec kthe wheels and tyres of
your vehicle for damage (e.g. cuts, punctu-
res, tears, bulges on tyres and deformation,
cracks or severe corrosion on wheels), at
least every 14 days, as well as after driving
off-road or on rough roads. Damaged
wheels can cause a loss of tyre pressure.
R Regularly check the tyre tread depth and
the condition of the tread across the whole
width of the tyre (Y page 359). If neces-
sary, turn the front wheels to full lock in
order to inspect the inner side of the tyre
surface.
R All wheels must have a valve cap to protect
the valve against dirt and moisture. Do not
fit anything onto the valve (such as tyre
pressure monitoring systems) other than
the standard valve cap or other valve caps
approved by Mercedes-Ben zfor your vehi-
cle.
R Regularly check the pressure of all the tyres
including the emergency spare wheel or the
spare wheel, particularly prior to long trips,
and correc tthe pressure as necessary
(Y page 361). 358
OperationWheels and tyres

Tyre tread
G
WARNING
Bear in mind that:
R tyre grip decreases rapidly on we troads
when the tread depth is less than 3mm.
Thus, you should replace tyres that have
insufficient tread.
R winter tyres should be replaced when the
tread depth is 4mmorless as they no lon-
ger provide adequate grip.
R the tread on a tyre may not wear evenly.
Thus, you should regularly check the tread
depth and the condition of the tread across
the entire width of all tyres. If necessary,
turn the fron twheels to full lock in order to
inspect the tyre tread more easily.
Otherwise, you could lose control of the vehi-
cle and cause an accident due to the reduced
grip of the tyres on the road. Notes on selecting, fitting and replac-
ing tyres
R Only fit tyres and wheels of the same type
and make.
R Only fit tyres of the correct size onto the
wheels.
R After fittingn ew tyres, run them in at mod-
erate speeds for the first 100 km, as they
only reach their full performance after this
distance.
R Do not drive with tyres which have too little
tread depth, as this significantly reduces
the traction on wet roads (aquaplaning).
R Replace the tyres after six years at the lat-
est, regardless of wear. This also applies to
the emergency spare wheel/spare wheel. MOExtended tyres (tyres with run-flat
characteristics)
MOExtended tyres (tyres with run-flat char-
acteristics) allow you to continue driving the vehicle even when one or more tyres lose all
air pressure.
MOExtended tyres may only be used in con-
junction with the tyre pressure loss warning
system or with the tyre pressure monitor and
on wheels specifically tested by Mercedes-
Benz.
i Vehicles with MOExtended tyres are not
equipped with a TIREFIT kit at the factory.
It is therefore recommended that you addi-
tionally equip your vehicle with the TIREFIT
kit if you fit tyres that do not feature run-
flat properties, e.g. winter tyres. A TIREFIT
kit can be obtained from a Mercedes-Benz
Service Centre.
Notes on driving with MOExtended tyres in
the event of a flat tyre can be found in the
"Breakdown assistance" section
(Y page 345). Winter operation
Points to remember
At the onset of winter, have your vehicle win-
terproofed at a qualified specialist workshop,
e.g. at a Mercedes-Benz Service Centre.
Observe the notes in the "Changing a wheel"
section (Y page 365). Driving with summer tyres
At temperatures below +7 †, summer tyres
lose elasticity and therefore traction and
braking power; change the tyres on your vehi-
cle to M+S tyres. Using summer tyres at very
cold temperatures could cause tears to form,
thereby damaging the tyres permanently.
Mercedes-Benzc annot accept responsibility
for this type of damage. Winter operation
359Wheels and tyres Z