2014 MERCEDES-BENZ C-CLASS SALOON trailer

Problems with trailer towing
Problem
Possible causes/consequences and
M
MSolutions The released ball cou-
pling cannot be
engaged. X
Visit a qualified specialist workshop. The ball coupling does
not unlock, even
though:
R the vehicle is station-
ary
R no trailer cable is
connected
R the release knob to
unlock the ball cou-
pling has been pulled
for more than a sec-
ond. The on-board voltage is insufficient.
X Start the engine.
If the ball coupling still does not unlock: X Visit a qualified specialist workshop. Towing a trailer
289Driving and parking Z

Safety systems
Display messages
Possible causes/consequences and
M
MSolutions !÷
currently unavail‐ currently unavail‐
able See Owner's able See Owner's
Manual Manual ABS (Anti-lock Brake System), ESP
®
(Electronic Stability Program),
BAS (Brake Assist System), PRE‑ SAFE®
, HOLD function, hill start
assist, ESP ®
trailer stabilisation, Crosswind Assist, adaptive brake
lights, STEER CONTROL, Active Lane Keeping Assist and Active
Blind Spot Assist are temporarily unavailable.
BAS PLUS, PRE‑SAFE ®
Brake, PRE‑SAFE ®
PLUS and COLLISION
PREVENTION ASSIST PLUS may also have failed.
In addition, the ÷,åand! warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
For example, the on-board voltage may be insufficient.
G WARNING
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely affec-ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
Carefully drive on a suitable stretch of road, making slight steer-
ing movements at a speed above 20 km/h.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit a qualified specialist workshop. !÷
inoperative See inoperative See
Owner's Manual Owner's Manual ABS, ESP
®
, BAS, PRE‑SAFE ®
, HOLD function, hill start assist,
ESP ®
trailer stabilisation, Crosswind Assist, adaptive brake lights,
STEER CONTROL, Active Lane Keeping Assist and Active Blind
Spot Assist are unavailable due to a malfunction.
BAS PLUS, PRE‑SAFE ®
Brake, PRE‑SAFE ®
PLUS and COLLISION
PREVENTION ASSIST PLUS may also have failed.
The J, ÷, åand! warning lamps may also light up
in the instrument cluster.
ATTENTION ASSIST is deactivated. Display messages
315On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions G
WARNING
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely affec- ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. ÷
inoperative See inoperative See
Owner's Manual Owner's Manual ESP
®
, BAS, PRE ‑SAFE®
, HOLD function, hill start assist,
ESP ®
trailer stabilisation, Crosswind Assist, adaptive brake lights,
STEER CONTROL, Active Lane Keeping Assist and Active Blind
Spot Assist are unavailable due to a malfunction.
BAS PLUS, PRE‑SAFE ®
Brake, PRE ‑SAFE®
PLUS and COLLISION
PREVENTION ASSIST PLUS may also have failed.
In addition, the ÷andå warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions listed above.
The braking distance may thus increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop. 316
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions ÷
currently unavail‐ currently unavail‐
able See Owner's able See Owner's
Manual Manual ESP
®
, BAS, PRE ‑SAFE®
, HOLD function, hill start assist,
ESP ®
trailer stabilisation, Crosswind Assist, adaptive brake lights,
STEER CONTROL, Active Lane Keeping Assist and Active Blind
Spot Assist are unavailable due to a malfunction.
BAS PLUS, PRE‑SAFE ®
Brake, PRE ‑SAFE®
PLUS and COLLISION
PREVENTION ASSIST PLUS may also have failed.
In addition, the ÷andå warning lamps light up in the
instrument cluster.
The self-diagnosis function, for example, may not be complete.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you
brake hard, for example.
The braking distance may thus increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Carefully drive on a suitable stretch of road, making slight steer-
ing movements at a speed above 20 km/h.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit a qualified specialist workshop. Display
messages
317On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions T!
÷
inoperative See inoperative See
Owner's Manual Owner's Manual EBD (electronic brake force distribution), ABS, ESP
®
, BAS,
PRE ‑SAFE ®
, HOLD function, hill start assist, ESP ®
trailer stabili-
sation, Crosswind Assist, adaptive brake lights, STEER CONTROL, Active Lane Keeping Assist and Active Blind Spot Assist are
unavailable due to a malfunction.
BAS PLUS, PRE‑SAFE ®
Brake, PRE ‑SAFE®
PLUS and COLLISION
PREVENTION ASSIST PLUS may also have failed.
In addition, the ÷,åand! warning lamps light up in the
instrument cluster and a warning tone sounds.
G WARNING
The brake system continues to function normally, but without the functions listed above. The front and rear wheels could therefore
lock, for example, if you brake hard.
The steerability and braking characteristics may be severely affec-ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. J
Brake immediately Brake immediately A malfunction has occurred while the HOLD function is active.
or
With the HOLD function activated, you have:
R opened the driver's door and released the seat belt or
R switched off the engine
A tone may also sound at regular intervals. If you attempt to lock the vehicle, the tone becomes louder.
You cannot start the engine.
X Paying attention to the traffic situation, immediately depress the
brake pedal firmly and hold until the display message disap-
pears.
X Secure the vehicle against rolling away (Y page 207).
You can restart the engine. !
Release parking Release parking
brake brake The red
!indicator lamp flashes and a warning tone sounds. A
condition for automatic release of the electric parking brake is not
fulfilled (Y page 209).
You are driving with the electric parking brake applied.
X Release the electric parking brake manually. 318
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions front-passenger front airbag deactivation system has disa-
bled the front-passenger front airbag (Y
page 54).
R the display messages Front-passenger Front-passengerairbag
airbagenabled
enabled
See
See Owner's
Owner's Manual
ManualorFront-passenger
Front-passenger airbag
airbagdisa‐
disa‐
bled See Owner's Manual
bled See Owner's Manual must not appear in the multi-
function display.
X Wait for a period of at least 60 seconds until the necessary sys-
tem checks have been completed.
X Make sure that the display messages do not appear in the mul-
tifunction display.
If these conditions are met, the front-passenger seat can be occu- pied again. Whether the PASSENGER AIRBAG OFF or ON indicator
lamp remains lit or goes out depends on how the automatic front- passenger front airbag deactivation system classifies the occu-
pant.
If the conditions are not met, the system is not operating correctly.
X Visit a qualified specialist workshop immediately.
Further information on the automatic front-passenger front airbag deactivation feature (Y page 54).Lights
i Display messages about LEDs:
This display message will only appear if all the LEDs have failed. Display messages
Possible causes/consequences and
M MSolutions b
Left cornering Left cornering
light light
orRight cor‐
Right cor‐
nering light
nering light The left or right-hand cornering light is faulty.
X Visit a qualified specialist workshop. b
Left dipped beam Left dipped beam
or
Right dipped Right dipped
beam beam The left or right-hand dipped-beam headlamp is faulty.
X Check whether you are permitted to replace the bulb yourself
(Y page 142).
or
X Visit a qualified specialist workshop. b
Trailer left tail Trailer left tail
lamp lampor
Trailer
Trailer
right tail lamp right tail lamp The left or right-hand trailer tail lamp is faulty.
X Observe the separate operating instructions provided by the
trailer manufacturer. Display
messages
329On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions b
Trailer left indi‐ Trailer left indi‐
cator catororTrailer
Trailer
right indicator
right indicator The left or right-hand trailer turn signal lamp is faulty.
X Observe the separate operating instructions provided by the
trailer manufacturer. b
Trailer brake lamp Trailer brake lamp The trailer brake lamp is faulty.
X Observe the separate operating instructions provided by the
trailer manufacturer. b
Rear left indica‐ Rear left indica‐
tor tor
orRear right
Rear right
indicator
indicator The rear left-hand or rear right-hand turn signal is faulty.
X Check whether you are permitted to replace the bulb yourself
(Y page 142).
or
X Visit a qualified specialist workshop. b
Front left indica‐ Front left indica‐
tor tor
orFront right
Front right
indicator
indicator The front left-hand or front right-hand turn signal is faulty.
X Check whether you are permitted to replace the bulb yourself
(Y page 142).
or
X Visit a qualified specialist workshop. b
Left Left
mirror
mirror indica‐
indica‐
tor
tor orRight mir‐
Right mir‐
ror indicator
ror indicator The turn signal in the left-hand or right-hand exterior mirror is
faulty.
X Visit a qualified specialist workshop. b
Left brake lamp Left brake lamp
or
Right brake lamp
Right brake lamp The left or right-hand brake lamp is faulty.
X Visit a qualified specialist workshop. b
Third brake lamp Third brake lamp The third brake lamp is faulty.
X Visit a qualified specialist workshop. b
Left-hand tail Left-hand tail
lamp/ brake lamp/ brake
lamp lampor
Right-hand
Right-hand
tail lamp/ brake
tail lamp/ brake
lamp lamp The left or right-hand tail lamp/brake lamp is faulty.
X Visit a qualified specialist workshop. 330
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions b
Malfunction See Malfunction See
Owner's Manual 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 424).
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 AUTO
lights
lights inoper‐
inoper‐
ative
ative The light sensor is faulty.
X Visit a qualified specialist workshop. b
Switch off lights 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 Highbeam Adaptive Highbeam
Assist Assist
Plus
Plusinoper‐
inoper‐
ative
ative Adaptive Highbeam Assist Plus is faulty.
X Visit a qualified specialist workshop. Adaptive Highbeam
Adaptive Highbeam
Assist Plus cur‐ Assist Plus cur‐
rently rently
unavailable
unavailable
See Owner's Manual
See Owner's Manual Adaptive Highbeam Assist Plus 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
X Clean the windscreen.
If the system detects that the camera is fully operational, display
message Adaptive
Adaptive Highbeam
HighbeamAssist
Assist Plus
Plusavailable
available again
again
is displayed.
Adaptive Highbeam Assist Plus is operational again. 332
Display
messagesOn-board computer and displays