2011 MERCEDES-BENZ C-CLASS SALOON check engine

Display messages Possible causes/consequences and
M Solutions
Check trailer
hitch lock G
Risk of accident
Vehicles with a retractable trailer coupling:
The trailer tow hitch is no tcorrectly engaged.
Aw arning tone also sounds.
X Stop the vehicle immediately, paying attentio ntoroad and traf-
fic conditions, and switch off the engine.
X Apply the parking brake.
X Allow the trailer tow hitch ball coupling to engage in the end
position (Y page 217). Pwr. steering
malfunc. G
Risk of accident
The power steering assistance is faulty. You will need to use more
force to steer.
Aw arning tone also sounds.
X Chec kwhether you are able to apply the extra force required.
X If you are able to steer safely: carefully drive on to a qualified
specialist workshop.
X If you are unable to steer safely: do not drive on. Contact the
nearest qualified specialist workshop. Top up
washer fluid The washer fluid level in the washer fluid reservoir has dropped
below the minimum.
X
Top up the washer fluid (Y page 325).Vehicle (12-button multifunction steering wheel)
Display messages Possible causes/consequences and
M Solutions
To start engine,
shift to either P
or N You have attempted to start the engine with the transmission in
position
Ror D.
X Shift the transmission to position Por N. P
Select Park (P) You have switched off the engine with the Start/Stop button and
opened the driver's door.
You wanted to lock the vehicle.
Aw
arning tone also sounds.
or
You have switched off the engine with the Start/Stop butto nand
opened the driver's door with the transmission in position N.
X Shift the transmission to position P. Display messages
285On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
j
Check trailer
hitch lock G
Risk of accident
The trailer tow hitch is no tcorrectly engaged.
Aw arning tone also sounds.
X Stop the vehicle immediately, paying attentio ntoroad and traf-
fic conditions, and switch off the engine.
X Apply the parking brake.
X Allow the trailer tow hitch ball coupling to engage in the end
position (Y page 217). D
Power
steering mal‐
function See Own‐
er's Manual G
Risk of accident
The power steering assistance is faulty.
You will need to use more force to steer.
Aw arning tone also sounds.
X Chec kwhether you are able to apply the extra force required.
X If you are able to steer safely: carefully drive on to a qualified
specialist workshop.
X If you are unable to steer safely: do not drive on. Contact the
nearest qualified specialist workshop. &
inoperative Bat‐
tery low The on-board voltage is too low. The auxiliary heating has switched
itself off or cannot be switched on (Y page 143).
X Drive for a longer distance.
The battery is being charged. The auxiliary heating is operational
again as soon as the on-board electrical system voltage is suf-
ficient. &
inoperative
Refuel
vehicle The fuel level in the fuel tank is too low. The auxiliary heating can-
not be switched on (Y page 143).
X Refuel at the nearest filling station. &
inoperative See
Owner's Manual The auxiliary heating has a temporary malfunction or is faulty.
X
When the vehicle is on alevel surface and the engine has cooled
down, make up to four attempts to switch on the auxiliary heat-
ing, waiting several minutes between each attempt
(Y page 143).
X If the auxiliary heating does not switch on, consult a qualified
specialist workshop. Display messages
287On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions
J֌!
The red brake warning
lamp, the yellow ESP
®
and ESP ®
OFF warning
lamps and the yellow
ABS warning lamp are
lit while the engine is
running. G
Risk of accident
ABS and ESP ®
are malfunctioning. Therefore, BAS, BAS PLUS,
EBD, PRE-SAFE ®
, PRE-SAFE ®
Brake, the HOLD function, hill start
assist, the adaptive brake lights and ESP ®
trailer stabilisation, for
example, are not available either.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
ATTENTION ASSIST is deactivated.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. ÷
The yellow ESP
®
warn-
ing lamp flashes while
the vehicle is in motion. G
Risk of accident
ESP ®
or traction control has intervened because there is a risk of
skidding or at least one wheel has started to spin.
Cruise control or DISTRONIC PLUS is deactivated.
X Only depress the accelerator pedal as far as necessary when
pulling away.
X Accelerate more gently during the journey.
X Adapt your driving style to suit the road and weather conditions.
X Vehicles with a 12-button multifunction steering wheel only: do
not deactivate ESP ®
.
Exceptions: (Y page 75). å
Vehicles with a 12-but-
ton multifunction steer-
ing wheel only:
The yellow ESP
®
OFF
warning lamp is lit while
the engine is running. G
Risk of accident
ESP ®
and ESP ®
trailer stabilisation are deactivated. ESP ®
will not
stabilise the vehicle if it starts to skid or if awheel starts to spin.
X Reactivate ESP ®
.
For exceptions, see: (Y page 75).
X Adapt your driving style to suit the road and weather conditions.
If ESP ®
cannot be activated:
X Have ESP ®
checked at a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
295On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions
M
AMG vehicles only:
The yellow SPORT han-
dling mode warning
lamp is lit while the
engine is running.
G
Risk of accident
SPORT handling mode is activated. ESP ®
only stabilises the vehi-
cle in extreme situations. ESP ®
intervention may not be able to
provide sufficient assistance in such situations, and the vehicle
may start to skid.
X Reactivate ESP ®
.
For exceptions, see: (Y page 75).
If ESP ®
cannot be activated:
X Have ESP ®
checked at a qualified specialist workshop. ֌
The yellow ESP
®
and
ESP ®
OFF warning
lamps are lit while the
engine is running. G
Risk of accident
ESP ®
, BAS, BAS PLUS, PRE-SAFE ®
, PRE-SAFE ®
Brake, the HOLD
function, hill start assist, the adaptive brake lights and ESP ®
trailer
stabilisation are not available due to a malfunction .ESP ®
will not
stabilise the vehicle if it starts to skid or if awheel starts to spin.
The brake system continues to function normally, but without the
functions listed above.
ATTENTION ASSIST is deactivated.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. 296
Warning and indicator lamps in the instrument clusterOn-board computer and displays

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 173).
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 when 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 Apply the parking brake.
X Consult a qualified specialist workshop. 298
Warning and indicator lamps in the instrument clusterOn-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
Pull release lever :on the bonnet.
The bonnet is released.
! Make sure that the windscreen wipers are
not folded away from the windscreen .Oth-
erwise, you could damage the windscreen
wipers or the bonnet. X
Reach into the gap, pull bonnet catch han-
dle ;up and lift the bonnet.
If you lift the bonnet by approximately
40 cm, the bonnet is opened and held open
automatically by the gas-filled strut.
Closing the bonnet G
WARNING
Make sure tha tnobody can become trapped
as you close the bonnet. X
Lower the bonnet and let it fall from a
height of approximately 20 cm.
X Check that the bonnet has engaged prop-
erly.
If the bonnet can be raised slightly, it is not
properly engaged. Open it again and close
it with a little more force. Radiator
i Vehicles with diesel engine: do not
cover the radiator. Do not use thermal
mats, insect protection covers or anything
similar. Doing so can cause the Onboard
Diagnostics System to display inaccurate
values. Some of these values are legally
required and must be correct. Engine oil
Notes on the oil level Depending on driving style, the vehicle con-
sumes a maximum of 0.8 l oil per 1000 km.
The oil consumption may be higher than this
when the vehicle is new or if you frequently
drive at high engine speeds.
Checking the oil level using the oil dip-
stick
Example: vehicles with a petrol engine Engine compartment
323Maintenance and care Z

Example: vehicles with a diesel engine
X
Park the vehicle on a level surface.
To check the oil level with the engine at
normal operating temperature, switch the
engine off and wait for approximately five
minutes.
X Pull oil dipstick :outoft he oil dipstick
tube.
X Wipe off oil dipstick :.
X Slowly slide oil dipstick :into the guide
tube to the stop, and take it out again.
If the level is between MIN mark =and
MAX mark ;, the oil level is correct.
X If the oil level has dropped to MIN mark
= or below it, top up with
0.5 to 1.0 litres of engine oil.
Adding engine oil G
WARNING
If engine oil comes into contact with hot
engine parts, it may ignite and you could burn
yourself. Do not spill any engine oil on hot
engine parts. H
Environmental note
When topping up the oil, take care not to spill
any. If oil enters the soil or waterways, it is
harmful to the environment.
! Do not add too much oil. If the oil level is
above the "max" mark on the dipstick, too
much oil has been added. This can lead to
damage to the engine or the catalytic con-
verter. Have excess oil siphoned off. Example: engine oil cap
X
Turn cap :anti-clockwise and remove it.
X Top up the engine oil.
If the oil level is at or below the MIN mark
on the dipstick, top up with
0.5 to 1.0 litres of engine oil.
X Replace cap :on the filler neck and turn
clockwise.
Make sure that the cap locks into place
securely.
X Check the oil level again with the oil dip-
stick (Y page 323).
Further information on engine oil
(Y page 381). Checking and adding other service
products
Checking the coolant level Only check the coolant level when the vehicle
is on a level surface and the engine has cooled
down.
X Turn the key to position 2(Y page 153) in
the ignition lock.
On vehicles with KEYLESS-GO, press the
Start/Stop button twice (Y page 153).
X Check the coolant temperature display in
the instrument cluster. G
WARNING
The cooling system is pressurised. Therefore,
only unscrew the cap once the engine has
cooled down. The coolant temperature gauge 324
Engine compartmentMaintenance and care