Problem
Possible causes/consequences and
M
MSolutions You can no longer lock or
unlock the vehicle using
KEYLESS-GO. KEYLESS-GO has been deactivated.
X Reactivate KEYLESS-GO (Y page 83). The key battery is weak or discharged.
X Check the key battery (Y page 85) and replace if necessary
(Y page 85).
If this does not work: X Lock or unlock the vehicle using the emergency key element
(Y page 90). Interference from a powerful source of radio waves.
X Lock or unlock the vehicle using the emergency key element
(Y page 90). Fault with KEYLESS-GO.
X Lock or unlock the vehicle using the remote control function of the
key.
X Have the vehicle and key checked at a qualified specialist work-
shop.
If the vehicle cannot be locked or unlocked even using the remote
control function:
X Lock or unlock the vehicle using the emergency key element
(Y page 90).
X Have the vehicle and key checked at a qualified specialist work-
shop. The engine cannot be
started using the key. The on-board voltage is too low.
X Switch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
X Check the starter battery and charge it if necessary (Y page 347).
or X Jump-start the vehicle (Y page 348).
or X Consult a qualified specialist workshop. The engine cannot be
started using the Start/
Stop button. The key is in
the vehicle. The vehicle is locked.
X Unlock the vehicle and try to start the vehicle again. The key battery is weak or discharged.
X Check the key battery (Y page 85) and replace if necessary
(Y page 85).
If this does not work: X Start your vehicle with the key in the ignition lock. Interference from a powerful source of radio waves.
X Start your vehicle with the key in the ignition lock. Key
87Opening and closing Z
Problems with the seat heating / seat ventilation
Problem
Possible causes/consequences and
M
MSolutions The seat heating or seat
ventilation has switched
off prematurely or can-
not be switched on. The on-board voltage is too low because too many electrical consum-
ers are switched on.
X Switch off electrical consumers that you do not need, such as the
rear window heating or interior lighting.
Once the battery is sufficiently charged, the seat heating or seat
ventilation can be switched back on manually. Steering wheel
Important safety notes
G
WARNING
You could lose control of the vehicle while
driving if you:
R adjust the driver's seat, steering wheel or
mirrors
R fasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint, steer-
ing wheel and mirrors and fasten your seat
belt before starting the engine. G
WARNING
Children could become trapped by the steer-
ing wheel if they adjust it. There is a risk of
injury.
When leaving the vehicle, always take the key with you and lock the vehicle. Never leave
children unattended in the vehicle.
The electrically adjustable steering wheel can
still be adjusted when there is no key in the igni-
tion lock. Adjusting the steering wheel man-
ually
:
Release lever
; To adjust the steering wheel height
= To adjust the steering wheel position (fore-
and-aft adjustment)
X Push release lever :down completely.
The steering column is unlocked.
X Adjust the steering wheel to the desired posi-
tion.
X Push release lever :up as far as it will go.
The steering column is locked.
X Check that the steering column is locked.
When doing so, try to push the steering wheel
up or down or try to move it in the fore-and-aft
direction. 108
Steering wheelSeats, steering wheel and mirrors
Problems with the windscreen wipers
Problem
Possible causes/consequences and
M
MSolutions The windscreen wipers
are jammed. Leaves or snow, for example, are obstructing windscreen wiper move-
ment. The wiper motor has been deactivated.
X Switch off the engine.
X Remove the key from the ignition lock.
or, on vehicles with KEYLESS-GO or KEYLESS ‑GO start function:
X Open the driver's door.
The vehicle electronics now have status 0. This is the same as the
key having been removed.
X Remove the cause of the obstruction.
X Switch the windscreen wipers back on. The windscreen wipers
fail completely. The windscreen wiper drive is malfunctioning.
X Select another wiper speed on the combination switch.
X Have the windscreen wipers checked at a qualified specialist work-
shop. The windscreen washer
fluid from the spray noz-
zles no longer hits the
centre of the wind-
screen. The spray nozzles are misaligned.
X Have the spray nozzles adjusted at a qualified specialist workshop. 126
Windscreen wipersLights and windscreen wipers
G
WARNING
Flammable materials introduced through
environmental influence or by animals can
ignite if in contact with the exhaust system or parts of the engine that heat up. There is a risk
of fire.
Carry out regular checks to make sure that
there are no flammable foreign materials in
the engine compartment or in the exhaust
system.
General notes Vehicles with a petrol engine:
the catalytic
converter is preheated for up to 30 seconds
after a cold start. The sound of the engine may
change during this time.
Automatic transmission X
Shift the transmission to position j
(Y page 154).
The transmission position indicator on the
multifunction display shows j
(Y page 155).
i You can start the engine in transmission
position jand i.
Starting procedure using the key To start the engine using the key instead of the
Start/Stop button, pull the Start/Stop button
out of the ignition lock.
X To start a diesel engine: turn the key to
position 2in the ignition lock (Y page 144).
The % preglow indicator lamp on the
instrument cluster lights up.
X Turn the key to position 3in the ignition lock
(Y page 144) and release it as soon as the
engine is running.
i Vehicles with a diesel engine:
you can
start the engine without preglow if the engine
is warm.
If the engine will not start:
X Remove the key from the ignition lock.
X Reinsert the key in the ignition lock after wait-
ing for a short period. X
Turn the key to position 2in the ignition lock
(Y page 144).
The indicator lamps on the instrument cluster
light up (Y page 280).
X Turn the key to position 3in the ignition lock
(Y page 144) and release it as soon as the
engine is running.
Starting procedure using the Start/
Stop button The Start/Stop button is available only on vehi-
cles with KEYLESS-GO or the KEYLESS-GO start
function.
The Start/Stop button can be used to start the
vehicle manually without inserting the key in the ignition lock. The key must be in the vehicle and
the Start/Stop button must be inserted in the
ignition lock. This mode for starting the engine
manually operates independently of the ECO
start/stop automatic engine start function.
You can start the engine if a valid key is in the
vehicle. Switch off the engine and always take
the key with you when leaving the vehicle, even
if you leave it for only a short time. Observe the important safety notes.
X Depress the brake pedal and keep it
depressed.
X Press the Start/Stop button once
(Y page 144).
Vehicles with a petrol engine: the engine
starts.
Vehicles with a diesel engine: preglow is
activated and the engine starts. Pulling away
General notes G
WARNING
If the engine speed is above the idling speed
and you engage transmission position Dor R,
the vehicle could pull away suddenly. There is a risk of an accident.
When engaging transmission position Dor R,
always firmly depress the brake pedal and do not simultaneously accelerate.
Depress the accelerator carefully when pulling
away. 146
DrivingDriving and parking
Problem
Possible causes/consequences and
M
MSolutions The engine does not
start. The starter motor
can be heard. The
reserve fuel warning
lamp is lit and the fuel
gauge display is at the
reserve level. The fuel tank is empty.
X Refuel the vehicle. The engine does not
start. You cannot hear
the starter motor. The on-board voltage is too low because the battery is too weak or
discharged.
X Jump-start the vehicle (Y page 348).
If the engine does not start despite attempts to jump-start it:
X Consult a qualified specialist workshop. The starter motor was exposed to excessively high thermal load.
X Start the engine again (Y page 145).
If the engine still does not start: X Consult a qualified specialist workshop. Vehicles with a petrol
engine:
The engine is not running
smoothly and is misfir-
ing. The engine electronics or a mechanical component of the engine
management system are/is malfunctioning.
X Depress the accelerator pedal only slightly.
Otherwise, non-combusted fuel may get into the catalytic converter
and damage it.
X Have the cause rectified immediately at a qualified specialist work-
shop. The coolant temperature
display is showing more
than 120 †. A display
message may also
appear on the multifunc-
tion display and a warn-
ing tone may sound. The coolant level is too low. The coolant is too hot and the engine is not
being cooled sufficiently.
X Stop as soon as possible and allow the engine and the coolant to
cool down.
X Check the coolant level (Y page 329). Observe the warning notes
as you do so and top up the coolant if necessary. If the coolant level is correct, the engine radiator fan may be faulty. The
coolant is too hot and the engine is not being cooled sufficiently.
X If the coolant temperature is below 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 in moun-
tainous terrain and stop-start traffic. Driving
151Driving and parking Z
X
If this is the case, park the vehicle only on
level ground and secure it to prevent it from
rolling away.
X Shift the automatic transmission to position
P.
It may not be possible to release an applied
parking brake if the on-board voltage is low or if there is a malfunction in the system. Contact a
qualified specialist workshop.
The electric parking brake carries out a function
check at regular intervals when the engine is
switched off. Noises that occur are normal.
Applying or releasing manually X
To apply: push handle :.
When the electric parking brake is applied,
red indicator lamp !lights up on the
instrument cluster.
The electric parking brake can also be applied when the key is removed.
X To release: pull handle:.
Red indicator lamp !on the instrument
cluster goes out.
The electric parking brake can be released only:
R when the key is in position 1or 2in the igni-
tion lock (Y page 144) or
R if the ignition was switched on using the
Start/Stop button
Applying automatically The electric parking brake is automatically
applied when the transmission is in position P
and:
R the engine is switched off or
R the driver is not wearing a seat belt and the
driver's door is opened To prevent the electric parking brake from being
applied automatically, pull handle :.
The electric parking brake is also applied auto-
matically if:
R DISTRONIC PLUS brings the vehicle to a
standstill or
R the HOLD function is keeping the vehicle sta-
tionary or
R Active Parking Assist is keeping the vehicle
stationary
In addition, at least one of the following condi-
tions must be fulfilled:
R the engine is switched off
R the driver is not wearing a seat belt and the
driver's door is opened
R there is a system malfunction
R the power supply is insufficient
R the vehicle is stationary for a lengthy period
Red indicator lamp !on the instrument clus-
ter lights up.
The electric parking brake is not automatically
applied if the engine is switched off by the ECO
start/stop function.
Releasing automatically The electric parking brake of your vehicle is
released automatically when all the following
conditions are fulfilled:
R the seat belt is fastened
R the engine is running
R you accelerate and the transmission is in
position Dor R
or
you shift the transmission position from Pto
position Dor R– You will need to accelerate
more on steeper gradients
If the transmission is in position R, the tailgate
must be closed.
If your seat belt is not fastened, the following
conditions must be fulfilled for the electric park- ing brake to be released automatically:
R the driver's door is closed
R you are shifting from transmission position P
or you have previously driven at speeds
greater than 3 km/h
Ensure that you do not depress the accelerator
pedal unintentionally. Otherwise, the parking
brake will be released and the vehicle will start
to move. Parking
169Driving and parking Z
If cruise control is deactivated, a warning tone
sounds. You will see the Cruise control off
Cruise control off
message on the multifunction display for
approximately five seconds. The message on
the multifunction display disappears and the
segments on the speedometer go out.
i The last speed stored is cleared when you
switch off the engine. SPEEDTRONIC
General notes SPEEDTRONIC is used to set a speed limit for
your vehicle. If the vehicle speed exceeds the
set speed limit, SPEEDTRONIC brakes automat- ically. Shift to a lower gear in good time on long
and steep downhill gradients. Take particular
note of this when driving a laden vehicle and
when towing a trailer. By doing so, you will make use of the braking effect of the engine. This
relieves the load on the brake system and pre-
vents the brakes from overheating and wearing too quickly.
Important safety notes SPEEDTRONIC can neither reduce the risk of an
accident if you fail to adapt your driving style nor override the laws of physics. SPEEDTRONIC
cannot take into account road, weather or traffic
conditions. SPEEDTRONIC is only an aid. You
are responsible for maintaining a safe distance
from the vehicle in front, for vehicle speed, for
braking in good time and for staying in lane.
If there is a change of drivers, advise the new
driver of the speed stored.
You can set a variable or permanent limit speed:
R variable for speed limits, e.g. in built-up areas
R permanent for long-term speed restrictions,
e.g. when driving with winter tyres fitted
(Y page 177)
i The speed indicated in the speedometer
may differ slightly from the limit speed stored. Variable SPEEDTRONIC General notes
:
To store the current speed or a higher speed
; LIM indicator lamp
= To store the current speed or calling up the
last stored speed
? To store the current speed or a lower speed
A To switch between cruise control or
DISTRONIC PLUS and variable SPEED-
TRONIC
B Deactivating variable SPEEDTRONIC
With the cruise control lever, you can operate
cruise control or DISTRONIC PLUS and variable SPEEDTRONIC.
The LIM indicator lamp on the cruise control
lever indicates which system you have selected:
R LIM indicator lamp off: cruise control or
DISTRONIC PLUS is selected
R LIM indicator lamp on: variable SPEED-
TRONIC is selected
You can use the cruise control lever to limit the speed to any speed above 30 km/h while the
engine is running. If you have set a permanent
limit speed, you can variably limit the speed up
to the fixed limit speed (Y page 177).
Selecting variable SPEEDTRONIC
If there is a change of drivers, advise the new
driver of the limit speed stored. X Check whether LIM indicator lamp ;is on.
If it is on, variable SPEEDTRONIC is already
selected.
If it is not, press the cruise control lever in the direction of arrow A.
LIM indicator lamp ;in the cruise control
lever is on. Variable SPEEDTRONIC is selec-
ted. 176
Driving systemsDriving and parking
In particular, the detection of obstacles can be
impaired in the case of:
R dirt on the sensors or obscured sensors
R snow or heavy rain
R interference by other radar sources
R strong radar reflections, e.g. in multi-storey
car parks
If DISTRONIC PLUS no longer detects a vehicle
in front, it may unexpectedly accelerate to the
speed stored.
This speed can:
R be too high for a filter lane or a slip road
R be so high in the right lane that you pass vehi-
cles driving on the left (in countries where
they drive on the right)
R be so high in the left lane that you pass vehi-
cles driving on the right (in countries where
they drive on the left)
If there is a change of drivers, advise the new
driver of the speed stored.
Cruise control lever :
To activate or increase speed
; Setting the specified minimum distance
= LIM indicator lamp
? To activate at the current speed/last stored
speed
A To activate or reduce speed
B To switch between DISTRONIC PLUS and
variable SPEEDTRONIC
C Deactivating DISTRONIC PLUS
You can operate variable SPEEDTRONIC and
DISTRONIC PLUS with the cruise control lever. LIM indicator lamp
=on the cruise control lever
indicates which function you have selected:
R LIM indicator lamp= =lit:variable SPEED-
TRONIC is selected.
R LIM indicator lamp = =off:DISTRONIC PLUS
is selected
When you activate DISTRONIC PLUS, the
stored speed will appear on the multifunction display for five seconds.
Speedometer with segments: when
DISTRONIC PLUS is activated, the segments
from the stored speed to the end of the scale or to a permanently set speed limit light up.
Selecting DISTRONIC PLUS X
Check whether LIM indicator lamp =is off.
If it is off, DISTRONIC PLUS is already selec-
ted.
X If it is not, move the cruise control lever in the
direction of arrow B.
LIM indicator lamp =in the cruise control
lever goes out. DISTRONIC PLUS is selected.
Activating DISTRONIC PLUS Activation conditions
To activate DISTRONIC PLUS, the following con-
ditions must be fulfilled:
R The engine must be running. It may take up to
two minutes of driving before DISTRONIC
PLUS is ready for use.
R The electric parking brake must be released.
R ESP ®
must be switched on, but must not cur-
rently engage.
R Active Parking Assist must not be activated.
R The transmission must be in position D.
R The driver's door must be closed or your seat
belt must be fastened when you shift from P
to D.
R The front-passenger door and the rear doors
must be closed.
R The DISTRONIC PLUS function must be selec-
ted (Y page 179). Driving systems
179Driving and parking Z