tow MERCEDES-BENZ C-CLASS SALOON 2014 Repair Manual

Towing a trailer
Important safety notes
G
WARNING
The braking system can overheat if you leave your foot on the brake pedal while driving.
This increases the braking distance and could
even cause the braking system to fail. There is
a risk of an accident.
Never use the brake pedal as a footrest. Do
not simultaneously depress both the brake
pedal and the accelerator pedal while driving. G
WARNING
You could lose control of the vehicle/trailer
combination if it begins to swerve. The vehi-
cle/trailer combination could even overturn.
There is a risk of an accident.
On no account should you attempt to
straighten out the vehicle/trailer combina-
tion by increasing speed. Decrease your
speed and do not countersteer. Brake if nec-
essary. G
WARNING
If the maximum the permissible load for a car- rier system is exceeded, the carrier could
come loose from the vehicle and endanger
other road users. There is a risk of an accident and injury.
Never exceed the permissible noseweight
when using a carrier.
Exceeding the maximum permissible nose-
weight of the trailer drawbar on the ball cou-
pling may cause damage to the following:
R your vehicle
R the trailer
R the ball coupling
R the trailer tow hitch
The vehicle/trailer combination could
become unstable.
If the noseweight used is lower than the min- imum permissible noseweight, the vehicle/ trailer combination could also become unsta-
ble.
To avoid hazardous situations:
R make sure to check the noseweight before
each journey.
R use a drawbar noseweight as close as pos-
sible to the maximum noseweight.
R do not exceed the maximum permissible
noseweight.
R do not use a noseweight lower than the
minimum permissible trailer drawbar nose-
weight.
Make sure that the following values are not
exceeded:
R the permissible trailer drawbar noseweight
R the permissible trailer load
R the permissible rear axle load of the towing
vehicle
R the maximum permissible gross vehicle
weight of both the towing vehicle and the
trailer
The applicable permissible values, which
must not be exceeded, can be found:
R in your vehicle documents
R on the identification plates of the trailer tow
hitch and the trailer
R on the vehicle identification plate
If the values differ, the lowest value applies.
You will find the values approved by the man-
ufacturer on the vehicle identification plates
and those for the towing vehicle under "Tech- nical data" (Y page 478). G
WARNING
If you release the ball coupling or it does not
engage correctly when folding in, it will swing out. Within pivoting range of the ball coupling,
there is an increased risk of an accident and
injury.
Only release the ball coupling if the pivoting
range is unobstructed. Always make sure that the ball coupling engages when folding in. Towing a trailer
283Driving and parking Z

!
Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
When reversing the vehicle towards the
trailer, make sure there is nobody between
the trailer and the vehicle.
Couple and uncouple the trailer carefully. If
you do not couple the trailer to the towing
vehicle correctly, the trailer could become
detached.
When towing a trailer, your vehicle's handling
characteristics will be different in comparison to when driving without a trailer.
The vehicle/trailer combination:
R is heavier
R is restricted in its acceleration and gradi-
ent-climbing capability
R has an increased braking distance
R is affected more by strong crosswinds
R demands more sensitive steering
R has a larger turning circle
This can impair the vehicle's handling char-
acteristics. Adapt your driving style accord-
ingly. Maintain a safe distance. Drive care-
fully.
When towing a trailer, always adjust your
speed to the current road and weather con-
ditions. Do not exceed the maximum permis- sible speed for your vehicle/trailer combina-
tion. Notes on towing a trailer
General notes Trailer towing is not permissible on the fol-
lowing models:
R C 180 BlueEFFICIENCY Edition
R C 220 BlueTEC BlueEFFICIENCY Edition
When towing a trailer, set the tyre pressure on
the rear axle of the towing vehicle for a max-
imum load; see the tyre pressure table in the fuel filler flap (Y page 432). On vehicles without level control, the height
of the ball coupling will alter according to the
load placed on the vehicle. If necessary, use a
trailer with a height-adjustable drawbar.
You will find fitting dimensions and loads
under "Technical data" (Y page 477).
When towing a trailer, the ECO start/stop
function is deactivated. The èECO sym-
bol appears yellow in the multifunction dis-
play. For further information on the ECO
start/stop function; see (Y page 186).
Driving tips Observe the notes on ESP
®
trailer stabilisa-
tion (Y page 82).
The maximum permissible speed for vehicle/ trailer combinations depends on the type of
trailer. Before beginning the journey, check
the trailer's documents to see what the max- imum permitted speed is. Observe the legally
prescribed maximum speed in the relevant
country.
For certain Mercedes-Benz vehicles, the max-
imum permissible rear axle load is increased
when towing a trailer. See the "Technical
data" section to find out whether this applies
to your vehicle (Y page 478). If you utilise any
of the added maximum rear axle load when
towing a trailer, the vehicle/trailer combina-
tion may not exceed a maximum speed of
100 km/h for reasons concerning the oper-
ating permit. This also applies in countries in
which the permissible maximum speed for
vehicle/trailer combinations is above
100 km/h.
When towing a trailer, your vehicle's handling
characteristics will be different in comparison to when driving without a trailer and it will
consume more fuel.
Change into a lower gear in good time on long
and steep downhill gradients.
This also applies if cruise control, DISTRONIC
PLUS or SPEEDTRONIC are activated.
This will use the braking effect of the engine,
so less braking will be required to maintain
vehicle speed. This relieves the load on the 284
Towing a trailerDriving and parking

brake system and prevents the brakes from
overheating and wearing too quickly. If you
need additional braking, depress the brake
pedal repeatedly rather than continuously.
Driving tips If the trailer swings from side to side:
X Do not accelerate.
X Do not countersteer.
X Brake if necessary.
R Maintain a greater distance to the vehicle in
front than when driving without a trailer.
R Avoid braking abruptly. If possible, brake
gently at first to allow the trailer to run on.
Then, increase the braking force rapidly.
R The values given for gradient-climbing
capabilities from a standstill refer to sea
level. When driving in mountainous areas,
note that the power output of the engine,
and consequently the vehicle's gradient-
climbing capability, decrease with increas-
ing altitude. Folding out the ball coupling
G
WARNING
If the ball coupling is not correctly engaged,
the trailer can detach. There is a risk of an
accident.
Always engage the ball coupling as described. G
WARNING
If you release the ball coupling or it does not
engage correctly when folding in, it will swing out. Within pivoting range of the ball coupling,
there is an increased risk of an accident and
injury.
Only release the ball coupling if the pivoting
range is unobstructed. Always make sure that the ball coupling engages when folding in.
Before you can tow a trailer with your vehicle, you must fold out the ball coupling.
X Make sure that the vehicle is stationary. X
Open the boot lid.
X Pull release knob :until the ball coupling
unlocks.
The ball coupling folds out from under the
rear bumper.
The indicator lamp on the release knob
flashes. The trailer socket folds away auto- matically. X
Press the ball coupling in the direction of
the arrow until it engages in a vertical posi-
tion.
The indicator lamp on the release knob
goes off.
The multifunction display shows the
Trailer Trailer hitch
hitchCheck
Checklock
lockmech.
mech. mes-
sage until the ball coupling is engaged.
X Remove the protective covering from the
ball coupling and store it in a safe place.
Hybrid vehicles: observe the safety instruc-
tions for hybrid vehicles (Y page 269). Towing a trailer
285Driving and parking Z

Coupling up a trailer
X Make sure that the transmission is in posi-
tion P.
X Apply the electric parking brake.
X Position the trailer horizontally behind the
vehicle.
X Couple up the trailer.
X Establish the electric connection between
the vehicle and the trailer.
X Check that the trailer lighting system is
working.
X Push the combination switch upwards/
downwards and check whether the corre-
sponding turn signal on the trailer is flash-
ing.
A connected trailer is only recognised when the electrical connection is established
correctly and when the lighting system is
working properly. The functioning of other
systems, e.g. ESP ®
, PARKTRONIC, Active
Parking Assist, Active Blind Spot Assist or
Lane Keeping Assist also depends on this. Uncoupling a trailer
G
WARNING
If you uncouple a trailer with an engaged over- run brake, you could trap your hand between
the vehicle and the trailer drawbar. This poses a risk of injury.
Do not uncouple a trailer with an engaged
overrun brake. G
WARNING
Vehicles with level control:
If you disconnect the trailer cable, the vehicle is lowered. This can cause you or others to
become trapped between the vehicle body
and tyres, or underneath the vehicle. This
poses a risk of injury.
Make sure that no-one is in the immediate
vicinity of the wheel arch or underneath the
vehicle when disconnecting the trailer cable. !
Do not disconnect a trailer with an
engaged overrun brake. Otherwise, your
vehicle could be damaged by the rebound- ing of the overrun brake.
! Remove the installed adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumper and the adapter cable.
X Make sure that the transmission is in posi-
tion P.
X Apply the electric parking brake.
X Secure the trailer against rolling away.
X Remove the trailer cable and decouple the
trailer. Folding in the ball coupling
G
WARNING
If you release the ball coupling or it does not
engage correctly when folding in, it will swing out. Within pivoting range of the ball coupling,
there is an increased risk of an accident and
injury.
Only release the ball coupling if the pivoting
range is unobstructed. Always make sure that the ball coupling engages when folding in.
Fold the ball coupling back in if you are not
using the trailer tow hitch. X Make sure that the vehicle is stationary and
the trailer cables are disconnected.
X Place the protective covering on the ball
coupling.
X Open the boot lid. 286
Towing a trailerDriving and parking

X
Pull release knob :until the ball coupling
unlocks.
The ball coupling folds down from under the rear bumper. The indicator lamp on the
release knob flashes.
Do not attempt to speed this process up by
applying additional pressure with your foot. The system could otherwise be mechani-
cally damaged. X
Press the ball coupling in the direction of
the arrow until it engages audibly behind
the bumper.
The indicator lamp on the release knob
goes out and the message in the multifunc-
tion display disappears. Trailer power supply
! You can connect accessories with a
power rating of up to 240 W to the perma-
nent power supply and with a power rating of up to 180 W to the power supply that is
switched on via the ignition lock. The trailer battery may not be charged from
the power supply.
When it leaves the factory, your vehicle's
trailer socket is equipped with a permanent
power supply and a power supply that is
switched on via the ignition lock.
The permanent power supply is supplied via
trailer socket pin 9.
The power supply that is switched on via the
ignition lock is supplied via trailer socket pin
10.
The trailer's permanent power supply is
switched off in the event of low vehicle supply
voltage and after six hours at the latest.
You can find more information about fitting
the trailer electrics at a qualified specialist
workshop.
X To switch the connected power supply
on or off: turn the key in the ignition lock to
position 2or 0respectively (Y page 181). Bulb failure indicator for LED lamps
If LED lamps are fitted in the trailer, an error
message may appear in the multifunction dis-
play even if there is no fault. The reason for
the error message may be that the current
has fallen below the minimum of 50 mA.
To ensure reliable operation of the bulb failure indicator, each LED chain in the trailer lighting
must be guaranteed a minimum current of
50 mA. Trailer with 7-pin connector
General notes Trailer with 7-pin connector:
you can con-
nect to the 13-pin socket on the ball coupling
using an adapter or, if necessary, an adapter
cable. Both can be obtained at a qualified
specialist workshop. Towing a trailer
287Driving and parking Z

Fitting the adapter
!
Make sure that there is sufficient cable
play so that the cable cannot become
detached when cornering.
! Remove the installed adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumper and the adapter cable. X
Open the socket cover.
X Insert the plug connector with lug :into
groove =on the socket. Turn bayonet con-
nection ;clockwise to the stop.
X Let the cover engage.
X If you are using an adapter cable, secure
the cable to the trailer with cable ties. 288
Towing a trailerDriving and pa
rking

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

Lane not recommended
B: you will not be
able to complete the next change of direction
if you stay in this lane.
Possible lane A: you will be able to complete
the next change of direction in this lane only.
Recommended lane ?: in this lane you will
be able to complete the next change of direc- tion and the one after that.
Change of direction without lane recom-
mendation :
Road to which the change of direction
leads
; Distance to change of direction and visual
distance display
= Change-of-direction symbol
When a change of direction is to be made, you will see symbol =for the change of direction
and distance graphic ;. This shortens
towards the top of the display as you
approach the point of the announced change
of direction. The change of direction starts
once the distance display reaches zero. Change of direction with lane recommen-
dation :
Road to which the change of direction
leads
; Distance to change of direction and visual
distance display
= Change-of-direction symbol
? Lane recommendation
Other status indicators of the naviga-
tion system :
Additional information
Other possible additional information:
R New New route...
route... orCalculating
Calculating route...
route...
A new route is calculated.
R Road not mapped
Road not mapped
The vehicle position is inside the area of the
digital map but the road is not recognised,
e.g. off-road position.
R No route No route
No route could be calculated to the selec-
ted destination.
R O Menus and submenus
301On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions The red
!indicator lamp flashes and the yellow !warning
lamp is lit.
The electric parking brake is malfunctioning.
To release:
X Switch off the ignition and turn it back on.
X Release the electric parking brake manually.
To apply:
X Switch off the ignition and turn it back on.
X Apply the electric parking brake manually.
If the red !indicator lamp continues to flash:
X Do not drive on.
X Secure the vehicle against rolling away (Y page 439).
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Turn the front wheels towards the kerb.
X Consult a qualified specialist workshop. The yellow
!warning lamp lights up. The red !indicator
lamp flashes for about ten seconds after the electric parking brake
has been applied or released. It then goes out or remains lit.
The electric parking brake is malfunctioning.
X Switch off the ignition and turn it back on.
X Apply the electric parking brake.
If it is not possible to apply the electric parking brake:
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Consult a qualified specialist workshop.
If it is not possible to release the electric parking brake manually:
X Release the electric parking brake automatically (Y page 209).
If the electric parking brake still cannot be released: X Consult a qualified specialist workshop. 320
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