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168Driving and operatingNotice
Only use the designated AdBlue
canisters for refilling, to prevent a
topping-up of too much AdBlue.
Additionally, the fumes in the tank
are captured in the canister and do
not emerge.
Since AdBlue has a limited
durability, check the date of expiry
before refilling.
Notice
A volume of at least 5 litres of AdBlue must be added when refilling.
Otherwise the refilling of AdBlue
may not be detected by the system.
In case AdBlue refill is not
successfully detected:
1. Continuously drive the vehicle for 10 minutes making sure that
vehicle speed is always higher
than 12 mph.
2. If AdBlue refill is detected successfully, AdBlue supply
driven limitations will disappear.If AdBlue refill is still not detected
seek the assistance of a workshop.
If AdBlue must be refilled at
temperatures below -11 °C, the
refilling of AdBlue may not be
detected by the system. In this
event, park the vehicle in a space
with a higher ambient temperature until AdBlue is liquefied.
Notice
When unscrewing the protective cap
from the filler neck, ammonia fumes
may emerge. Do not inhale as the
fumes have a pungent smell. The fumes are not harmful by inhalation.
The vehicle must be parked on a level surface.
The filler neck for AdBlue is located
behind the fuel filler flap.
The fuel filler flap is located at right
rear side of the vehicle.
The fuel filler flap can only be opened
if the vehicle is unlocked.
1. Remove key from ignition lock.
2. Close all doors to avoid ammonia fumes entering the interior of the
vehicle.3. Pull fuel filler flap at the recess and open 3 212.
4. Unscrew protective cap from the
filler neck.
5. Open AdBlue canister.
6. Mount one end of the hose on the
canister and screw the other end
on the filler neck.
7. Lift the canister until it is empty.
8. Unscrew the hose from the filler neck.
9. Mount the protective cap and turn
clockwise until it engages.
Page 171 of 307
Driving and operating169Notice
Dispose of AdBlue canister and
hose according to environmental
requirements.
Exchanging AdBlue
If less than five litres of AdBlue have
been refilled during the last two years, the remaining fluid should be
exchanged since AdBlue has a
limited durability. Seek the assistance of a workshop.Caution
Disregard could lead to damage to
the selective catalytic reduction
system.
Automatic transmission
The automatic transmission permits
automatic gearshifting (automatic
mode) or manual gearshifting
(manual mode).
Transmission display
The mode or selected gear is shown
in the transmission display.
Selector leverP:park position, wheels are locked,
engage only when the vehicle is
stationary and the parking brake
is appliedR:reverse gear, engage only when
the vehicle is stationaryN:neutralD:automatic mode with all gears
The selector lever is locked in P and
can only be moved when the ignition
is on and the brake pedal is applied.
Page 174 of 307
172Driving and operating
3. Insert a screwdriver into theopening as far as it will go and
move the selector lever out of P or
N . If P or N is engaged again, the
selector lever will be locked in
position again. Have the cause of
the power supply interruption
remedied by a workshop.
4. Mount the selector lever trim onto
the centre console and refit.
Manual transmission
To engage reverse, with the vehicle
stationary, depress clutch pedal,
press the release button on the
selector lever and engage the gear.
If the gear does not engage, set the
lever to neutral, release the clutch
pedal and depress again; then repeat
gear selection.
Do not slip the clutch unnecessarily.
When operating, depress the clutch
pedal completely. Do not use the
pedal as a foot rest.
Caution
It is not advisable to drive with the hand resting on the selector lever.
Page 175 of 307

Driving and operating173Brakes
The brake system comprises two
independent brake circuits.
If a brake circuit fails, the vehicle can
still be braked using the other brake
circuit. However, braking effect is
achieved only when the brake pedal
is depressed firmly. Considerably
more force is needed for this. The
braking distance is extended. Seek the assistance of a workshop before
continuing your journey.
When the engine is not running, the
support of the brake servo unit
disappears once the brake pedal has
been depressed once or twice.
Braking effect is not reduced, but
braking requires significantly greater
force. It is especially important to bear this in mind when being towed.
Control indicator R 3 111.
Antilock brake system
Antilock brake system (ABS)
prevents the wheels from locking.ABS starts to regulate brake pressure as soon as a wheel shows a tendency to lock. The vehicle remains
steerable, even during hard braking.
ABS control is made apparent
through a pulse in the brake pedal
and the noise of the regulation
process.
For optimum braking, keep the brake
pedal fully depressed throughout the
braking process, despite the fact that
the pedal is pulsating. Do not reduce
the pressure on the pedal.
After starting off the system performs
a self-test which may be audible.
Control indicator u 3 112.
Adaptive brake light
During full braking, all three brake
lights flash for the duration of ABS
control.Fault9 Warning
If there is a fault in the ABS, the
wheels may be liable to lock due
to braking that is heavier than
normal. The advantages of ABS are no longer available. During
hard braking, the vehicle can no longer be steered and may
swerve.
Have the cause of the fault remedied
by a workshop.
Page 187 of 307

Driving and operating1859Warning
The driver accepts full
responsibility for the appropriate
following distance based on traffic, weather and visibility conditions.
Following distance must be
adjusted or the system switched
off when required by the prevailing
conditions.
Detecting the vehicle ahead
The green illuminated "vehicle
ahead" control indicator A is
displayed in the speedometer when the system detects a vehicle in the
driving path.
If this symbol does not appear, or
appears briefly, adaptive cruise
control will not respond to vehicles
ahead.
Deactivation
Adaptive cruise control is deactivated by the driver when:
● y is pressed.
● Brake pedal is applied.
● Clutch pedal is depressed for more than four seconds.
● Gear selector lever of automatic transmission is moved to N.
The system is also automatically deactivated when:
● Vehicle speed slows down below
28 mph or accelerates above
120 mph.
● Traction Control system is operating for more than
20 seconds.● Electronic Stability Control is operating.
● There is no traffic and nothing detected on the road sides forseveral minutes. In this case
there are no radar echoes and
the sensor may report that it is
blocked.
● Collision imminent braking system is applying the brakes.
● Radar sensor is blocked by an ice
or water film.
● A fault is detected in the radar, engine or brake system.
When adaptive cruise control is
deactivated automatically, the control indicator m illuminates white and a
warning symbol is displayed as a pop- up in the Driver Information Centre.
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186Driving and operating
The stored speed is maintained.
9Warning
When adaptive cruise control is
deactivated, the driver must take
over full brake and engine control.
Switching off
Press C to switch off adaptive cruise
control. The control indicator m
extinguishes. The stored speed is
deleted.
Switching off the ignition also
switches off adaptive cruise control
and deletes the stored speed.
Driver's attention
● Use adaptive cruise control carefully on bends or mountain
roads, as it can lose the vehicle
ahead and require time to detect
it again.
● Do not use the system on slippery roads as it can create
rapid changes in tyre traction
(wheel spinning), so that you
could lose control.
● Do not use adaptive cruise control during rain, snow or
heavy dirt, as the radar sensor
can be covered by a water film,
dust, ice or snow. This reduces or completely suppresses the
visibility. In case of sensor
blockage, clean the sensor
cover.
System limits ● The system's automatic brake force does not permit hard
braking and the braking level
may not be sufficient to avoid a
collision.● After a sudden lane change, the system needs a certain time to
detect the next preceding
vehicle. So if a new vehicle is
detected, the system may
accelerate instead of braking.
● Adaptive cruise control does ignore the oncoming traffic.
● Adaptive cruise control does not brake for stopped vehicles,
pedestrians or animals.
Bends
The adaptive cruise control calculates
a predicted path based on the
centrifugal force. This predicted path
considers the current bend
characteristic, but cannot consider a
future bend change. The system may lose the current vehicle ahead or
consider a vehicle which is not in the
actual lane. This can happen when
Page 190 of 307
188Driving and operatingRadar unit
The radar unit is mounted behind the
radiator grille below the brand
emblem.
9 Warning
The radar unit was aligned
carefully during manufacture.
Therefore, after a frontal accident, do not use the system. The front
bumper may appear to be intact,
however the sensor behind can be
out of position and react
incorrectly. After an accident,
consult a workshop to verify and
correct the adaptive cruise control
sensor position.
Settings
Settings can be changed in the Auto
collision preparation menu in the
vehicle personalisation 3 129.
Fault
If the adaptive cruise control does not
work due to temporary conditions
(e.g. blockage by ice) or if there is a
permanent system error, then a
message is displayed in the Driver
Information Centre.
Vehicle messages 3 122.
Forward collision alert The forward collision alert can help to
avoid or reduce the damage caused
by front-end crashes.
A vehicle ahead is indicated by a
control indicator A.
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192Driving and operatingapproaching a vehicle ahead too
rapidly, it may not provide you
enough time to avoid a collision.
The driver accepts full
responsibility for the appropriate
following distance based on traffic, weather and visibility conditions.
The complete attention of the
driver is always required while
driving. The driver must always be
ready to take action and apply the
brakes.
System limitations
The system is designed to warn only for vehicles, but may react also onother metallic objects.
In the following cases, forward
collision alert may not detect a vehicle ahead or sensor performance is
limited:
● on winding roads
● when weather limits visibility, such as fog, rain, or snow
● when the sensor is blocked by snow, ice, slush, mud, dirt, or
windscreen damage
Following distance
indication
The following distance indication
displays the distance to a preceding
moving vehicle. The system uses,
depending on the vehicle equipment,
either the radar behind the radiator
grille or the front camera in the
windscreen to detect the distance of
a vehicle directly ahead in your lane.
It is active at speeds above 25 mph.
When a preceding vehicle is detected ahead, the distance is indicated inseconds, displayed on a page in the
Driver Information Centre 3 116.
Press MENU on the turn signal lever
to select Vehicle Information Menu
X and turn the adjuster wheel to
choose following distance indication
page.
The minimum indicated distance is 0.5 s.
If there is no vehicle ahead or the
vehicle ahead is out of range, two
dashes will be displayed: -.- s.
Active Emergency Braking Active emergency braking can help toreduce the damage from crashes with
vehicles and obstacles directly
ahead, when a collision can no longer be avoided either by manual braking
or by steering. Before the active
emergency braking applies, the driver is warned by the forward collision
alert 3 188.