Problems with the fuel and fuel tank
Problem
Possible causes/consequences and
M
MSolutions Fuel is leaking from the
vehicle.
G
WARNING
The fuel line or the fuel tank is faulty.
There is a risk of fire or explosion. X Apply the electric parking brake.
X Switch off the engine.
X Remove the key from the ignition lock.
or, on vehicles with KEYLESS-GO start function or KEYLESS ‑GO:
X Open the driver's door.
The vehicle electronics now have status 0. This is the same as the
key having been removed.
X Do not restart the engine under any circumstances.
X Consult a qualified specialist workshop. The engine does not
start. The fuel tank of a vehicle with a diesel engine has been run completely
dry.
X Refuel the vehicle with at least 5 l of diesel.
X Turn the ignition on for approximately ten seconds (Y page 144).
X Start the engine continuously for a maximum of ten seconds until it
runs smoothly.
If the engine does not start: X Turn the ignition on again for a maximum of ten seconds
(Y page 144).
X Start the engine again continuously for a maximum of ten seconds
until it runs smoothly.
If the engine does not start after three attempts:
X Consult a qualified specialist workshop. The fuel filler flap cannot
be opened. The fuel filler flap is not unlocked.
X Unlock the vehicle (Y page 83). The key battery is weak or discharged.
X Unlock the vehicle using the emergency key element (Y page 84).The fuel filler flap is unlocked, but the opening mechanism is jammed.
X Consult a qualified specialist workshop. AdBlue
®
(BlueTEC vehicles only)
General notes To function properly, BlueTEC exhaust gas after-
treatment must be operated with the reducing
agent AdBlue ®
. When the supply of AdBlue
®
is down to approx-
imately 3.0 l,the Refill AdBlue See
Refill AdBlue See
Owner’s Owner’s Manual
Manualmessage is shown on the mul-
tifunction display.
If you drive the vehicle at a speed greater than
15 km/h after topping up, the Refill
Refill AdBlue AdBlue
See Owner’s Manual
See Owner’s Manual message disappears
after approximately one minute. 164
RefuellingDriving an
d parking
Emergency braking
The vehicle can also be braked during an emer-
gency by using the electric parking brake.
X While driving, press handle :of the electric
parking brake (Y page 169).
The vehicle is braked as long as you keep
handle :of the electric parking brake
depressed. The longer electric parking brake
handle :is depressed, the greater the brak-
ing force.
During braking:
R a warning tone sounds
R the Release parking brake
Release parking brake display mes-
sage appears
R red indicator lamp !on the instrument
cluster flashes
When the vehicle has been braked to a stand-
still, the electric parking brake is applied. Parking up the vehicle
If you leave the vehicle parked up for longer than
four weeks, the battery may be damaged by
exhaustive discharging.
If you leave the vehicle parked up for longer than
six weeks, it may suffer from lack of use.
X Contact a qualified specialist workshop and
seek advice.
i You can obtain information on trickle charg-
ers from a qualified specialist workshop.
Hybrid vehicles: observe the notes on the high-
voltage battery in the separate Owner's Manual. Driving tips
General driving tips
Important safety notes G
WARNING
If you switch off the ignition while driving,
safety-relevant functions are only available
with limitations, or not at all. This could affect, for example, the power steering and the brake
boosting effect. You will require considerably
more effort to steer and brake. There is a risk of an accident. Do not switch off the ignition while driving.
Drive sensibly – save fuel Observe the following tips to save fuel:
X The tyres should always be inflated to the rec-
ommended tyre pressure.
X Remove unnecessary loads.
X Remove roof racks when they are not needed.
X Warm up the engine at low engine speeds.
X Avoid frequent acceleration or braking.
X Have all maintenance work carried out as
indicated by the service intervals in the Ser-
vice Booklet or by the service interval display.
Fuel consumption also increases when driving in
cold weather, in stop-start traffic, on short jour- neys and in hilly terrain. ECO display
The ECO display shows you how economical
your driving style is. The ECO display assists you in achieving the most economical driving style
for the selected settings and prevailing condi-
tions. Consumption can be significantly influ-
enced by your driving style. :
Acceleration
; Coasting
= Constant
? Additional range achieved
Range ?is shown under Bonus Bonusfr. fr.start
start and
represents the additional range achieved since
the beginning of the journey as a result of an
adapted driving style.
If the fuel level has dropped into the reserve
range, the Reserve fuel Reserve fuel display message is
shown instead of range ?on the multifunction 170
Driving tipsDriving and parking
Vehicles with COMAND Online multimedia
system: when you change lanes, DISTRONIC
PLUS monitors the right lane in the case of left-
side traffic or the left lane in the case of right-
side traffic.
Vehicles with Audio 20 multimedia system:
when you change lanes, DISTRONIC PLUS mon- itors the left lane on left-hand-drive vehicles or
the right lane on right-hand-drive vehicles.
Road and traffic conditions The following function is available only in vehi-
cles with the Driving Assistance Plus package.
The function is not operational in all countries.
DISTRONIC PLUS uses additional information
from your navigation system so that it can adapt to certain traffic situations.
This is the case if, while you are following a vehi-
cle, DISTRONIC PLUS is active and you:
R approach or drive around a roundabout
R approach a T-junction
R turn off at a motorway exit
R approach a tollgate
Even if the vehicle in front leaves the detection
range, DISTRONIC PLUS temporarily maintains
the current driving speed and does not acceler-
ate. This is based on the current map data in the navigation system.
Afterwards, the vehicle accelerates back to the
speed you set.
The system takes into account the fact that
overtaking on the right is not permitted on
motorways or high-speed major roads at speeds
of more than 80 km/h. The driving speed is
adjusted to the speed of the queue of vehicles in
the adjacent lane to the left.
Prevention of overtaking on the right applies to
countries where traffic drives on the right. In
countries where traffic drives on the left, over-
taking on the left is prevented accordingly. Stopping G
WARNING
When leaving the vehicle, even if it is braked
only by DISTRONIC PLUS, it could roll away if:
R there is a malfunction in the system or in
the voltage supply.
R DISTRONIC PLUS has been deactivated
with the cruise control lever, e.g. by a vehi-
cle occupant or from outside the vehicle.
R the electrical system in the engine com-
partment, the battery or the fuses have
been tampered with.
R the battery is disconnected.
R the accelerator pedal has been depressed,
e.g. by a vehicle occupant.
There is a risk of an accident.
If you wish to exit the vehicle, always turn off
DISTRONIC PLUS and secure the vehicle
against rolling away.
Further information on deactivating DISTRONIC PLUS (Y page 183).
If DISTRONIC PLUS detects that the vehicle in
front has stopped, it will cause your vehicle to
brake to a standstill.
Once your vehicle is stationary, it remains sta-
tionary and you do not need to depress the
brake.
After a short period, the vehicle is secured by
the electric parking brake, thus relieving the
service brake.
Depending on the specified minimum distance,
your vehicle will come to a standstill at a suffi-
cient distance behind the vehicle in front. The
specified minimum distance is set using the
control on the cruise control lever.
When DISTRONIC PLUS is activated, the trans-
mission is shifted automatically to position Pin
the following situations:
R the driver's seat belt is not fastened and the
driver's door is open
R The engine is switched off, unless it is auto-
matically switched off by the ECO start/stop
function Driving systems
181Driving and parking Z
Information on the multifunction display
If Steering Assist and Stop&Go Pilot are activa-
ted but not ready for a steering intervention,
steering wheel symbol :appears in grey. If the
system provides you with support by means of
steering interventions, symbol :is shown in
green.
Deactivating Steering Assist and Stop&Go
Pilot
X Press button ;.
Indicator lamp :goes out. The DTR+:
DTR+:
steering assist. off
steering assist. off message appears
on the multifunction display. Steering Assist
and Stop&Go Pilot are deactivated.
When DISTRONIC PLUS is deactivated or not
available, Steering Assist and Stop&Go Pilot are deactivated automatically. HOLD function
General notes The HOLD function can assist the driver in the
following situations:
R when pulling away, especially on steep slopes
R when manoeuvring on steep slopes
R when waiting in traffic
The vehicle is kept stationary without the driver having to depress the brake pedal.
The braking effect is cancelled and the HOLD
function deactivated when you depress the
accelerator pedal to pull away. Important safety notes G
WARNING
When leaving the vehicle, it can still roll away despite being braked by the HOLD function if:
R there is a malfunction in the system or in
the voltage supply
R the HOLD function is deactivated by the
accelerator pedal being depressed, e.g. by
a vehicle occupant
R the electrical system in the engine com-
partment, the battery or the fuses are tam-
pered with
R the battery is disconnected
There is a risk of an accident.
Before leaving the vehicle, always deactivate
the HOLD function and secure the vehicle
from rolling away.
! When DISTRONIC PLUS or the HOLD func-
tion is activated, the vehicle brakes automat- ically in certain situations.
To avoid damage to the vehicle, deactivate
DISTRONIC PLUS and the HOLD function in
the following or similar situations:
R when towing away
R in a car wash
Deactivating the HOLD function (Y page 187).
Activation conditions You can activate the HOLD function if all the fol-
lowing conditions are fulfilled:
R the vehicle is stationary
R the engine is running or it has been automat-
ically switched off by the ECO start/stop
function
R the driver's door is closed or your seat belt is
fastened
R the electric parking brake is released
R the transmission is in position h,kori.
R DISTRONIC PLUS is deactivated 186
Driving systemsDriving and pa
rking
Parking
G
WARNING
If you leave the vehicle when it is only being
braked by Active Parking Assist it could roll
away if:
R there is a malfunction in the system or in
the voltage supply.
R the electrical system in the engine com-
partment, the battery or the fuses are tam-
pered with.
R the battery is disconnected.
R the vehicle is accelerated, e.g. by a vehicle
occupant.
There is a risk of an accident.
Before leaving the vehicle, always secure it
against rolling away.
i When PARKTRONIC detects obstacles,
Active Parking Assist brakes automatically
during the parking process. You are respon-
sible for braking in good time.
X Stop the vehicle when the parking symbol
shows the desired parking space in the instru-
ment cluster.
X Shift the transmission to position R.
The Start
Start Park ParkAssist?
Assist? Yes:
Yes:OK
OKNo:
No:%
message appears in the multifunction display.
X To cancel the procedure: press the%
button on the multifunction steering wheel or pull away.
or
X To park using Active Parking Assist: press
the a button on the multifunction steering
wheel.
The Park Assist active Accelerate Park Assist active Accelerate
and brake
and brake Observe surroundings
Observe surroundings mes-
sage appears in the multifunction display.
X Release the multifunction steering wheel.
X Reverse the vehicle, being ready to brake at
all times. When reversing, drive at a speed
below 10 km/h. Otherwise, Active Parking
Assist will be cancelled.
Active Parking Assist brakes the vehicle to a
standstill when the vehicle approaches the
rear border of the parking space.
Manoeuvring may be required in tight parking
spaces. The
Park
Park Assist Assist active
activeSelect D
Select D Observe
Observe
surroundings
surroundings message appears in the multi-
function display.
X Shift the transmission to position Dwhile the
vehicle is stationary.
Active Parking Assist immediately steers in
the other direction.
The Park Assist active Accelerate Park Assist active Accelerate
and brake
and brake Observe surroundings
Observe surroundings mes-
sage appears in the multifunction display.
i You will achieve the best results by waiting
for the steering procedure to complete before
pulling away.
X Drive forwards and be ready to brake at all
times.
Active Parking Assist brakes the vehicle to a
standstill when the vehicle approaches the
rear border of the parking space.
Manoeuvring may be required in tight parking
spaces.
The Park Park Assist
Assist active
activeSelect R
Select R Observe
Observe
surroundings
surroundings message appears in the multi-
function display.
As soon as the parking procedure is complete,
the Park Assist switched off
Park Assist switched off message
appears and a warning tone sounds. The vehicle
is now parked.
The vehicle is kept stationary without the driver having to depress the brake pedal. The braking
effect is cancelled when you depress the accel-
erator pedal.
Active Parking Assist no longer supports you
with steering interventions and brake applica-
tions. When Active Parking Assist is finished,
you must steer and brake again yourself.
PARKTRONIC is still available.
Parking tips:
R The way your vehicle is positioned in the park-
ing space after parking is dependent on vari-
ous factors. These include the position and
shape of the vehicles parked in front of and
behind it and the conditions of the location. It may be the case that Active Parking Assist
guides you too far into a parking space, or not
far enough into it. In some cases, it may also
lead you across or onto the kerb. If necessary,
you should cancel the parking procedure with Active Parking Assist.
R You can also preselect transmission position
D. The vehicle redirects and does not drive as
far into the parking space. Should the trans-
mission change take place too early, the park- 196
Driving systemsDriving and parking
Coupling up a trailer
X Apply the electric parking brake manually.
X Shift the transmission to position P.
X Position the trailer on a level surface behind
the vehicle.
X Couple up the trailer.
X Establish the electrical connection between
the vehicle and the trailer.
X Check that the trailer lighting system is work-
ing.
X Push the combination switch upwards and
downwards and check whether the corre-
sponding turn signal indicator on the trailer is
flashing.
A connected trailer is only detected when the
electrical connection is established correctly
and the lighting system is working properly. The
function of other systems also depends on this, for example:
R ESP ®
R PARKTRONIC
R Active Parking Assist
R Active Blind Spot Assist
R Active Lane Keeping Assist 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 rebounding of the overrun
brake.
! Remove the adapter cable before folding in
the ball coupling. You could otherwise dam-
age the rear bumper and the adapter cable.
X Apply the electric parking brake manually.
X Shift the transmission to position P.
X Switch off the engine.
X Secure the vehicle and trailer against rolling
away.
X Remove the trailer cable and uncouple the
trailer. Trailer power supply
! Accessories with a maximum power con-
sumption of 180 W can be connected to the
permanent power supply.
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 on-board voltage
and after six hours at the latest.
You can find more information about installing
the trailer electrics at a qualified specialist work- shop.
To activate the switched power supply:
X Turn the key to position 2in the ignition lock
(Y page 144).
or
X Press the Start/Stop button twice on vehicles
with KEYLESS-GO or the KEYLESS-GO start
function (Y page 144).222
Towing a trailerDriving and parking
Display messages
Possible causes/consequences and
M
MSolutions The yellow
!warning lamp lights up. If you manually apply or
release the electric parking brake, the red !indicator lamp
flashes.
The electric parking brake is malfunctioning. The electric parking
brake cannot be applied manually.
X Shift the transmission to position P, as the electric parking brake is
not applied automatically.
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 169).!
Parking brake inop‐ Parking brake inop‐
erative erative 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, e.g. because of over-
voltage or undervoltage.
X Rectify the cause of the overvoltage or undervoltage, e.g. by charg-
ing the battery or restarting the engine.
X Apply or release the electric parking brake.
If the electric parking brake still cannot be applied or released: X Switch off the ignition and switch it back on.
X Apply or release the electric parking brake.
If the electric parking brake still cannot be released: X Consult a qualified specialist workshop.
If the electric parking brake still cannot be applied:
X Consult a qualified specialist workshop. The yellow
!warning lamp lights up and the red !indicator
lamp flashes.
The electric parking brake cannot be applied manually.
X Shift the transmission to position P.
X Consult a qualified specialist workshop. J
Check brake fluid Check brake fluid
level level There is insufficient brake fluid in the brake fluid reservoir.
In addition, the red Jwarning lamp lights up on the instrument
cluster and a warning tone sounds.
G WARNING
Braking efficiency may be impaired.
There is a risk of an accident!
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving.
X Secure the vehicle against rolling away (Y page 167).
X Consult a qualified specialist workshop.
X Do not top up the brake fluid. This does not correct the fault. 254
Display
messagesOn-board computer and displays
Display messages
Possible causes/consequences and
M
MSolutions #
See Owner's Manual See Owner's Manual The battery is no longer being charged.
A warning tone also sounds.
Possible causes:
R faulty alternator
R torn poly-V-belt
R a malfunction in the electronics
! Do not continue driving. The engine could otherwise overheat.
X Stop the vehicle immediately, paying attention to road and traffic
conditions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 167).
X Consult a qualified specialist workshop. #
Stop vehicle See Stop vehicle See
Owner's Manual Owner's Manual The battery is no longer being charged and the charge status is too
low.
A warning tone also sounds.
X Stop the vehicle immediately, paying attention to road and traffic
conditions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 167).
X Observe the instructions in the display #See
See Owner's Owner's Manual
Manual
message.
X Consult a qualified specialist workshop. #
Stop vehicle Leave Stop vehicle Leave
engine running engine running The battery charge status is too low.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving.
X Leave the engine running.
X Wait until the display message disappears before pulling away. #
Start engine See Start engine See
Owner's Manual Owner's Manual The engine is off and the charge status is too low.
X Switch off any electrical consumers that you do not need, such as
the rear window heating and interior lighting.
X Leave the engine running for a few minutes, or drive for an extended
period.
The battery charges. 264
Display
messagesOn-board computer and displays