2011 MERCEDES-BENZ C-CLASS SALOON Owners Manual

Display messages Possible causes/consequences and
M Solutions
While the HOLD function or DISTRONIC PLU
Sis active, you have:
R opened the driver's door and released the seat belt or
R switched off the engine or
R opened the bonnet
At one may also sound at regular intervals. The tone becomes
louder if you attempt to lock the vehicle.
You cannot start the engine.
X Shift the transmission to position P.
You can restart the engine. N Saloon: the boot lid is open.
X
Close the boot lid. A Estate: the tailgate is open.
X
Close the tailgate. Mor? G
Risk of accident
Vehicles with an anti-theft alarm system: the bonnet is open. A
warning tone also sounds.
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 Close the bonnet. C At least one door is open.
Awarning tone also sounds.
X Close all doors. _
Rear left seat
backrest not locked
or
Rear right seat backrest not locked G
Risk of injury
Saloon with through-loading feature in the rear bench seat:
The backres tinthe rear is not engaged on the left-hand and/or
right-hand side. Awarning tone also sounds.
X Push the backres tback until it engages. 286
Display messagesOn-board computer and displays

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

Display messages Possible causes/consequences and
M Solutions
Telephone No
Service Your vehicle is outside the network provider's transmitter/
receiver range.
X
Wait until the mobile phone operational readiness symbol
appears in the multifunction display. ¥
Top
up washer fluid The washer fluid level in th
ewasher fluid reservoir has dropped
below the minimum.
X Top up the washe rfluid (Y page 325). Key (4-button multifunction steering wheel)
Displa
ymessages Possible causes/consequences and
M Solutions
Key does not
belong to vehicle You have put the wrong key in the ignitio
nlock.
X Use the correct key. +
Replace key The key needs to be replaced.
X
Visit a qualified specialist workshop. +
Change battery The batteries of the KEYLESS-GO key are discharged.
X
Change the batteries (Y page 86).Key not detected
(Red display message) The KEYLESS-GO key is not in the vehicle.
Aw
arning tone also sounds.
If the engine is switched off, you can no longer loc kthe vehicle
centrally or start the engine.
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 Locate the KEYLESS-GO key. The KEYLESS-GO key is not detected while the engine is running
because there is interference from a strong source of radio waves.
Aw
arning tone also sounds.
X Pull ove rand stop the vehicle safely as soo nas possible, paying
attention to road and traffic conditions.
X Apply the parking brake.
X Operate the vehicle with the key in the ignition lock if necessary. 288
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
Key not detected
(White display mes-
sage) The KEYLESS-GO key cannot be detected at present.
X
Change the location of th ekey with the KEYLESS-GO functions
in the vehicle.
If the KEYLESS-GO key is still not detected:
X Change the location of the key with the KEYLESS-GO functions
in the vehicle.
X Operate the vehicle with the key in the ignition lock if necessary. +
Key still in vehi‐
cle The KEYLESS-GO key has been detected inside the vehicle during
locking.
X
Remove the KEYLESS-GO key from the vehicle. +
Insert key KEYLESS-GO is temporarily malfunctioning or is defective.
Awarn-
ing tone also sounds.
X Insert the key into the ignition lock and turn it to the desired
position.
X Visi taqualified specialist workshop. Close doors
to lock veh. At least one door is open.
Awarning tone also sounds.
X Close all doors and loc kthe vehicle again. Key (12-button multifunction steering wheel)
Display messages Possible causes/consequences and
M Solutions
Â
Key does not
belong to vehicle You have put the wrong key in the ignition lock.
X
Use the correct key. Â
Replace key The key needs to be replaced.
X Visit a qualified specialist workshop. Â
Change key batter‐
ies The batteries of the KEYLESS-GO key are discharged.
X
Change the batteries (Y page 86). Display messages
289On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
Â
Key not detec‐
ted (red display mes-
sage) The KEYLESS-GO key is not in the vehicle.
Aw
arning tone also sounds.
If the engine is switched off, you can no longer loc kthe vehicle
centrally or start the engine.
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 Locate the KEYLESS-GO key. The KEYLESS-GO key is not detected while the engine is running
because there is interference from a strong source of radio waves.
Aw
arning tone also sounds.
X Pull ove rand stop the vehicle safely as soo nas possible, paying
attention to road and traffic conditions.
X Apply the parking brake.
X Operate the vehicle with the key in the ignition lock if necessary. Â
Key not detected
(White display mes-
sage) The KEYLESS-GO key cannot be detected at present.
X
Change the location of the key with the KEYLESS-GO functions
in the vehicle.
If the KEYLESS-GO key is still not detected:
X Operate the vehicle with the key in the ignition lock if necessary. Â
Key still in vehi‐
cle The KEYLESS-GO key has been detected inside the vehicle during
locking.
X
Remove the KEYLESS-GO key from the vehicle. Â
Remove starting
button, then
insert key KEYLESS-GO is temporarily malfunctioning or is defective.
Awarn-
ing tone also sounds.
X Insert the key into the ignition lock and turn it to the desired
position.
X Visi taqualified specialist workshop. Â
Close doors to
lock vehicle At least one door is open.
Awarning tone also sounds.
X Close all doors and loc kthe vehicle again. 290
Display messagesOn-board computer and displays

Warning and indicator lamps in the instrument cluster
Seat belts
Problem Possible causes/consequences and
M Solutions
7
Only for certain coun-
tries: the red sea
tbelt
warning lamp lights up
for six seconds after
the engine starts. The seat belt warning lamp reminds the driver and fron
tpassenger
to fasten their seat belts.
X Faste nyour seat belt (Y page 53). 7
Only for certain coun-
tries: the red seat belt
warning lamp lights up
after the engine starts.
In addition, a warning
tone sounds for up to
six seconds.
G
Risk of injury
The driver's seat belt is not fastened.
X Fasten your seat belt (Y page 53).
The warning tone ceases. 7
The red seat belt warn-
ing lamp lights up after
the engine starts, as
soon as the driver's or
the front-passenger
door is closed.
G
Risk of injury
The driver or front passenger has not fastened their seat belt.
X Fasten your seat belt (Y page 53).
The warning lamp goes out. G
Risk of injury
There are objects on the front-passenger seat.
X Remove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out. Warning and indicator lamps in the instrument cluster
291On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions
7
The red seat belt warn-
ing lamp flashes and an
intermittenta udible
warning sounds. G
Risk of injury
The driver or fron tpassenger has no tfastened their seat belt .At
the same time, you are driving faste rthan 25 km/h or have briefly
driven faster than 25 km/h.
X Fasten your seat belt (Y page 53).
The warning lamp goes out and the intermittent warning tone
ceases. G
Risk of injury
There are objects on the front-passenger seat. At the same time,
you are driving faster than 25 km/h or have briefly driven faster
than 25 km/h.
X Remove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out and the intermittent warning tone
ceases. 292
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Safety systems
Problem Possible causes/consequences and
M Solutions
J
The red brake system
warning lamp comes on
while the engine is run-
ning. A warning tone
also sounds. G
Risk of accident
There is insufficient brake fluid in the fluid reservoir.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.
X Apply the parking brake.
X Consult a qualified specialist workshop immediately.
X Observe the additional display messages in the multifunction
display.
Do not top up the brake fluid. This does not correct the error. !
The yellow ABS warning
lamp is lit while the
engine is running. G
Risk of accident
ABS (Anti-lock Brake System) has been deactivated due to a fault.
For this reason, BAS (Brake Assist), BAS PLUS, ESP ®
(Electronic
Stability Program), PRE-SAFE ®
,P RE-SAFE ®
Brake ,the HOLD func-
tion, hill start assist, the adaptive brake lights and ESP ®
trailer
stabilisation are also deactivated, for example.
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.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic trans-
mission, will not be available. Warning and indicator lamps in the instrument cluster
293On-board computer and displays Z