2011 MERCEDES-BENZ C-CLASS SALOON display

Display messages Possible causes/consequences and
M Solutions
b
Left main beam
or
Right main beam The lef
torright-hand high beam is faulty.
X Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. b
Left fog lamp
or
Right fog lamp The left-hand or right-hand front foglamp is faulty.
X
Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. b
Rear fog lamp The rear foglamp is faulty.
X
Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. b
Front
left parking
lamp or
Front right parking lamp The front left or front right parking lamp is faulty.
X
Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. b
Reversing light The reversing lamp is faulty.
X
Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. b
Rear left side
marker lamp or
Rear right side marker lamp The rear left or right side marker lamp is faulty.
X
Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. b
Left daytime driv‐
ing lamp or
Right daytime driving
lamp The left or right-hand daytime driving lamp is defective.
X
Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. 266
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
b
Intell. Light Sys‐
tem inoperative The Intelligent Light Syste
mis faulty. The lights remain available
without the Intelligent Light System.
X Visit a qualified specialist workshop. b
Malfunction See
Owner's Manual The exterior lighting is faulty.
X
Visit a qualified specialist workshop. Vehicles with trailer tow hitch: a fuse may have blown.
X
Check the fuses (Y page 354).
X If necessary, replace the blown fuse. Observe the warning notes
as you do so.
If the display message continues to be displayed:
X Visit a qualified specialist workshop. b
AUTO
lights inoper‐
ative The light sensor is faulty.
X
Visit a qualified specialist workshop. b
Switch off lights The lights are still switched on when you leave the vehicle. A
warning tone also sounds.
X
Turn the light switch to Ã.Adaptive Main-beam
Assist inoperative Adaptive Highbeam Assist is faulty.
X
Visit a qualified specialist workshop. Adaptive Main-beam
Assist currently
unavailable See
Owner's Manual Adaptive Highbeam Assist is deactivated and temporarily inoper-
ative. 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.
X Cleant he windscreen.
If the system detects that the camera is fully operational again,
the Adaptive Main-beam Assist available again message
is displayed.
Adaptive Highbeam Assist is operational again. Display messages
267On-board computer and displays Z

Engine (4-button multifunction steering wheel)
Display messages Possible causes/consequences and
M Solutions
Top up
coolant 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. ?
Stop vehicle Sw.
eng. 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. 268
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 The engine oil level has dropped to the minimum level.
Aw
arning tone also sounds.
X Chec kthe oil level when next refuelling, at the latest
(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
269On-board computer and displays Z

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 (4-butto
nmultifunction steering wheel) Display messages Possible causes/consequences and
M Solutions
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). The HOLD function is deactivated. When the brak
epedal is firmly
depressed, an activation condition is not fulfilled.
Aw arning tone also sounds.
X Check the activation conditions for the HOLD function
(Y page 193). Cruise ctrl. / LIM
inoperative Cruise control and SPEEDTRONIC are malfunctioning.
Aw
arning tone also sounds.
X Visi taqualified specialist workshop. Limit
--- km/h While depressing the accelerator pedal beyond the pressure point
(kickdown), SPEEDTRONIC cannot be activated.
Cruise control
- - - km/h A condition for activating cruise control has not been met.
You have tried to store
aspeed below 30 km/h, for example.
X If conditions permit, drive faster than 30 km/h and store the
speed.
X Check the activation conditions for cruise control
(Y page 178). 120 km/h
120 km/h Only for certain countries: the maximum speed has been excee-
ded.
X
Drive slower. 272
Display messagesOn-board computer and displays

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