2011 MERCEDES-BENZ C-CLASS SALOON Owners Manual

Display messages Possible causes/consequences and
M Solutions
b
Trailer brake lamp The trailer brake lamp is faulty.
X
Chec kwhether you are permitted to change the bulb yourself.
or
X Visit a qualified specialist workshop. b
Rear
left indicator
or
Rear right indi‐ cator The rear left-hand or rear right-hand turn signal 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 indica‐
tor or
Front right indicator The front left-hand or front right-hand turn signal 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
mirror indica‐
tor or
Right mir‐ ror indicator The turn signal in the left-hand or right-hand exterior mirror is
faulty.
X
Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. b
Third brake lamp The third brake 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
Tail/brake lamp,
left or
Tail/brake lamp, right The left or right-hand tail lamp/brake 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 main beam
or
Right main beam The left or right-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. 262
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
b
Left fog lamp
or
Right fog lamp The left-hand or right-hand fron
tfoglamp 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 marker
lamp or
Rear right 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 dayt. driv‐ ing lamp The left or right 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. b
Malfunction The exterior lighting is faulty.
X
Visit a qualified specialist workshop. Display messages
263On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
Vehicles with trailer tow hitch
:afuse 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 senso
ris 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.Lights (12-button multifunction steering wheel)
i Display messages aboutL EDs:
This display message will only appear if all LEDs have failed. Display messages Possible causes/consequences and
M Solutions
b
Left cornering
light or
Right cor‐ nering light The left or right-hand cornering ligh
tis faulty.
X Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. b
Left dipped beam
or
Right dipped beam The left or right-hand dipped-beam headlamp is faulty.
X
Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. b
Trailer left tail
lamp or
Trailer right tail lamp The left or right-hand trailer tail lamp is faulty.
X
Check whether you are permitted to change the bulb yourself.
or
X Visit a qualified specialist workshop. 264
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
b
Trailer left indi‐
cator or
Trailer right indicator The lef
torright-hand trailer tur nsignal lamp is faulty.
X Check whether you are permitted to change the bulb yourself.
or
X Visit a qualified specialist workshop. b
Trailer brake lamp The trailer brake lamp is faulty.
X Check whether you are permitted to change the bulb yourself.
or
X Visit a qualified specialist workshop. b
Rear
left indicator
or
Rear right indi‐ cator The rear left-hand or rear right-hand tur
nsignal 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 indica‐
tor or
Front right indicator The front left-hand or front right-hand turn signal 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
mirror indica‐
tor or
Right mir‐ ror indicator The turn signal in the left-hand or right-hand exterior mirror is
faulty.
X Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. b
Third brake lamp The third brake 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-hand tail
lamp/brake lamp or
Right-hand tail lamp/brake lamp The left or right-hand tail lamp/brake lamp is faulty.
X
Check whether you are permitted to change the bulb yourself
(Y page 125).
or
X Visit a qualified specialist workshop. Display messages
265On-board computer and displays Z

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