Driving and operating173Driver assistance
systems9 Warning
Driver assistance systems are
developed to support the driver
and not to replace the driver's
attention.
The driver accepts full
responsibility when driving the
vehicle.
When using driver assistance
systems, always take care
regarding the current traffic
situation.
Cruise control
The cruise control can store and
maintain speeds of approx. 20 to
120 mph. Deviations from the stored
speeds may occur when driving uphill or downhill.
For safety reasons the cruise controlcannot be activated until the foot
brake has been operated once.
Activating in first gear is not possible.
Do not use the cruise control if it is not advisable to maintain a constant
speed.
With automatic transmission, only
activate cruise control in automatic
mode.
Control indicator m 3 109.
Switching on Press button m, control indicator m in
instrument cluster illuminates white.
Activation
Accelerate to the desired speed and
turn thumb wheel to SET/-: the
current speed is stored and
maintained. Control indicator m in
instrument cluster illuminates green.
Set speed is indicated on midlevel or
uplevel display near m symbol.
Accelerator pedal can be released.
Vehicle speed can be increased by depressing the accelerator pedal.
When the accelerator pedal is
released, the previously stored speed
is resumed.
Cruise control remains activated
while gearshifting.
176Driving and operating
to follow the vehicle in front, but will
not exceed the set speed. It may
apply limited braking with activated
brake lights.
The adaptive cruise control can store and maintain speeds over approx.
15 mph. If following a vehicle ahead
driving slower than 15 mph the slower
speed will be set. On vehicles with
automatic transmission the system brakes to a stop.
Adaptive cruise control uses a radar
sensor to detect the vehicles ahead.
If no vehicle is detected in the driving path, the adaptive cruise control will
behave like a traditional cruise
control.
For safety reasons, the system
cannot be activated before the brake
pedal or clutch pedal has been
depressed once since switching on
ignition.
Adaptive cruise control is mainly
advised to be used on long straight
roads like highways or country roads
with steady traffic. Do not use the
system if it is not advisable to
maintain a constant speed.
Control indicator A 3 109, m 3 109,
C 3 109.9 Warning
The complete driver attention is
always required while driving with adaptive cruise control. The driver stays fully in control of the vehicle
because the brake pedal, the
accelerator pedal and the cancel
switch have priority over any
adaptive cruise control operation.
Switching on
Press button C to switch on adaptive
cruise control. The control indicator
m or C in the instrument cluster
illuminates white.
Activation by setting the speed Adaptive cruise control can be
activated between 15 mph and
112 mph.
Accelerate to the desired speed and
turn thumb wheel to SET/-, the
current speed is stored and
maintained. Control indicator m or
C in the instrument cluster
illuminates green.
Driving and operating177
The adaptive cruise control symbol,
the following distance setting and set speed are indicated in the Driver
Information Centre.
The accelerator pedal can be
released. Adaptive cruise control
remains activated while gearshifting.
Overriding set speed It is always possible to drive faster
than the selected set speed by
depressing the accelerator pedal.
When the accelerator pedal is
released, the vehicle returns to the
desired distance if a slower vehicle is
ahead. Otherwise it returns to the
stored speed.
Once the system is activated,
adaptive cruise control decelerates or
brakes if it detects a vehicle ahead,
which is slower or closer than the
desired following distance.
9 Warning
Accelerating by the driver
deactivates braking by the system. This is indicated as a popup
warning in the Driver Information
centre.
Increase speed
With adaptive cruise control active,
hold thumb wheel turned to RES/+: speed increases continuously in large increments, or activate repeatedly
RES/+: speed increases in small
increments.
If the vehicle is driven with adaptive cruise control active much faster than
the desired speed, e.g. after
depressing the accelerator pedal,
then the current speed can be stored and maintained by turning the thumb
wheel to SET/-.
Reduce speed
With adaptive cruise control active,
hold thumb wheel turned to SET/-:
speed decreases continuously in
large increments, or activate
repeatedly SET/-: speed decreases in small increments.
If the vehicle is driven with adaptive cruise control active much slower
than the desired speed, e.g. because
of a slower vehicle ahead, then the
current speed can be stored and
maintained by turning the thumb
wheel to SET/-.
Resume stored speed
If the system is switched on but
inactive, then turn thumb wheel to
RES/+ at a speed above 15 mph to
resume the stored speed.
Full speed range adaptivecruise control on vehicles with
automatic transmission Full speed range adaptive cruisecontrol will maintain a following gap
behind a detected vehicle and slow
your vehicle to a stop behind that
vehicle.
When the vehicle ahead drives away
within two minutes, turn thumb wheel
to RES/+ or operate the accelerator
178Driving and operating
pedal to a speed of 6 mph to resume
full speed range adaptive cruise
control.
If the stopped vehicle ahead begins to move forward and full speed range
adaptive cruise control has not
resumed, the green illuminated
vehicle ahead control indicator A will
flash and a warning chime will sound
as a reminder that the vehicle ahead
is pulling away.
When the vehicle ahead stops for
more than two minutes, the electrical
parking brake will apply automatically and the full speed range adaptive
cruise control will be deactivated. In
this event, drive the vehicle normally
by operating the accelerator pedal.
Turn thumb wheel to RES/+ at a
speed above 6 mph to resume full
speed range adaptive cruise control.9 Warning
When full speed range adaptive
cruise control is deactivated or
cancelled, the vehicle will no
longer be held at a stop and can
start to move. Always be prepared to manually apply the brake to hold the vehicle stationary.
Do not leave the vehicle while it is being held at a stop by the full
speed range adaptive cruise
control. Always move selector
lever to park position P and switch
off the ignition before leaving the
vehicle.
Setting the following distance
When adaptive cruise control detects
a slower moving vehicle in the driving path, it will adjust the vehicle speed tomaintain the following distance
selected by the driver.
The following distance can be set to
near, medium or far.Press button E, the current setting is
shown in the Driver Information
Centre. Press button E again to
change the following distance. The
setting is also displayed in the Driver
Information Centre.
Driving and operating179
The selected following distance is
indicated by filled distance bars in the
adaptive cruise control page.
Note that the following distance
setting is shared with the sensitivity
setting of forward collision alert
3 183.
Example: If setting 3 (far) is selected,
then the driver is warned sooner
before a possible collision, also if
adaptive cruise control is inactive or
switched off.
9 Warning
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 when
the system detects a vehicle in the driving path.
Forward collision alert 3 183.
If this symbol does not display, or displays briefly, adaptive cruise
control will not respond to vehicles
ahead.
Deactivation
Adaptive cruise control is deactivated by the driver when:
■ button 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 accelerates above 120 mph or slows down below
9 mph (on vehicles with automatic
transmission it slows down to a stop without deactivating within
two minutes),
■ Traction Control system is operating,
■ Electronic Stability Control is operating,
■ there is no traffic and nothing detected on the road sides for
several minutes. In this case there
are no radar echoes and the sensor
may report that it is blocked,
180Driving and operating
■ collision imminent braking isapplying the brakes,
■ radar sensor is blocked by an ice or
water film,
■ fault is detected in the radar, engine
or brake system.
Additionally the system is
automatically deactivated on vehicles
with automatic transmission (full
speed range adaptive cruise control)
when:
■ Electric parking brake is applied,■ vehicle is being held to a stop by the
system for more than two minutes,
■ vehicle stops, the driver safety belt is released and the driver's door is
opened.
When adaptive cruise control is
deactivated automatically, the control indicator m or C illuminates white
and a warning message is displayed as a pop-up in the Driver Information
Centre.
The stored speed is maintained.9 Warning
When adaptive cruise control is
deactivated, the driver must take
over full brake and engine control.
Switching off
Press button C to switch off adaptive
cruise control. The control indicator
m or C 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 need 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 of the vehicle.
■ 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 suppresses completely
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.
182Driving and operating
Hill and trailer considerations
System performance on hills depends
on vehicle speed, vehicle load, traffic
conditions and the road gradient. It
may not detect a vehicle in your path
while driving on hills. On steep hills,
you may have to use the accelerator
pedal to maintain your vehicle speed.
When going downhill you may have to brake to maintain or reduce your
speed.
Note that applying the brake
deactivates the system. It is not
recommended to use adaptive cruise
control on steep hills.
Radar 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
vehicle personalisation menu in the
Colour-Info-Display.
Select the relevant setting in Settings,
I Vehicle in the Colour-Info-Display.
Colour-Info-Display 3 117.
Vehicle personalisation 3 121.
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.
Driving and operating183
Vehicle messages 3 119.
Forward collision alert The forward collision alert can help to
avoid or reduce the harm caused by
front-end crashes.
A vehicle ahead is indicated by a
control indicator A.
If a vehicle directly ahead is
approached too quickly, a warning
chime and alert in the Driver
Information Centre is provided.
A precondition is that forward collision
alert is activated in the vehicle
personalisation menu 3 121 or that it
is not deactivated by the button V
(depending on the system, see
below).
Depending on the vehicle's
equipment, there are two variants of
the forward collision alert available:
■ Forward collision alert based on
radar system
on vehicles equipped with adaptive cruise control 3 175.
■ Forward collision alert based on
front camera system
on vehicles with no cruise control or traditional cruise control only
3 173.
Forward collision alert based on radar system
The system uses the radar sensor
behind the radiator grille to detect a
vehicle directly ahead, in your path,
within a distance of max. 150 metres.
Activation
Forward collision alert operates
automatically above walking speed,
provided that Auto Collision
Preparation setting is not deactivated
in the vehicle personalisation menu
3 121.
Selecting the alert sensitivity
The alert sensitivity can be set to
near, medium or far.