MERCEDES-BENZ R320 2008 W251 Owner's Manual

270 Controls in detail
Driving systems
Setting a lower speed
You can reduce the set speed in two ways.Adjustment in 1 mph (Canada: 1 km/h)
increments
Briefly press the cruise control lever
down to the resistance point in
direction of arrow2 (
page 268).
Release the cruise control lever.
The vehicle set speed decreases in in-
crements of 1 mph (Canada: 1 km/h).
Adjustment in 5 mph
(Canada: 10 km/h) increments
Briefly press the cruise control lever
down past the resistance point in
direction of arrow2 (
page 268).
Release the cruise control lever.
The vehicle set speed decreases in
increments of 5 mph
(Canada: 10 km/h).
Warning!G
If you decrease the set vehicle speed, keep
in mind that it may take a brief moment until
the vehicle has reached the set speed.
Decrease the set vehicle speed to a value
that the prevailing road conditions and legal
speed limits permit. Otherwise, sudden and
unexpected acceleration of the vehicle
could cause an accident and/or serious
injury to you and others.
iWhen you use the cruise control lever to
decelerate, the brake system will automatically
brake the vehicle if the engine’s braking power
does not brake the vehicle sufficiently.
iThe set speed value is decreased in
1 mph (Canada: 1 km/h) increments each time
you press the cruise control lever down to the
resistance point.
iThe set speed value is decreased in 5 mph
(Canada: 10 km/h) increments each time you
press the cruise control lever down past the
resistance point.
iThe new speed is set and the vehicle will
decelerate. Keep in mind that it may take a brief
moment until the vehicle has reached the set
speed.

271 Controls in detail
Driving systems
Setting to last stored speed
(“Resume” function)
Briefly pull the cruise control lever in
direction of arrow4 (
page 268).
The Distronic resumes to the last set
speed.
Remove your foot from the accelerator
pedal.
The last set speed or, if no speed is stored,
the current set speed appears in the
multifunction display for approximately
5seconds.Deactivating Distronic
There are several ways to deactivate the
Distronic system:
Step on the brake pedal.
or
Briefly tip the cruise control lever in
direction of arrow3 (
page 268).
Distronic will be deactivated. The last set
speed will be stored in memory.
Warning!G
The set speed stored in memory should only
be set again if prevailing road conditions
permit. Possible acceleration or decelera-
tion differences arising from returning to the
preset speed could cause an accident
and/or serious injury to you and others.
iThe following message appears in the multi-
function display for approximately 5 seconds:
DISTRONIC Off.
The last stored set speed is deleted when the
engine is turned off.
iThe Distronic switches off automatically
when

you step on the brake pedal

you depress the parking brake pedal
In this case, the Distronic speed segments in the
speedometer (
page 265) will go out.

the vehicle speed is below 20 mph
(30 km/h)

the ESP® is in operation

the ESP® is switched off with the ESP®
switch (
page 104)

the ESP® has switched off due to a
malfunction (
page 435)

you set the automatic transmission toN
while driving
The Distronic speed segments in the speedome-
ter (
page 265) will go out and an acoustic
warning will sound.

272 Controls in detail
Driving systems
Setting the following distance in
Distronic
You can set the specified following
distance for Distronic by varying the time
setting between 1.0 and 2.0 seconds. Us-
ing this time setting and the current speed
of your vehicle, Distronic calculates and
sets the required following distance to the
preceding vehicle. The set distance will be
shown in the multifunction display
(
page 267).
The distance setting switch for the time
setting is located on the cruise control
lever on the left-hand side of the steering
column.
1Distance setting switch
2To decrease distance
3To increase distance
Warning!G
Distronic switches off and releases the
brakes when the vehicle decelerates below
the minimum speed of 20 mph (30 km/h)
by operation of the system. At that time the
driver must apply the brakes in order to
reduce vehicle speed further or bring it to
astop.
!Setting the automatic transmission toN
while driving cancels the Distronic. However, the
automatic transmission should not be set toN
while driving except to coast when the vehicle is
in danger of skidding (e.g. on icy roads).
iDepressing the accelerator pedal does not
deactivate the Distronic. After a brief accelera-
tion (e.g. for passing), the Distronic will resume
the last set speed.
Warning!G
It is up to the driver to exercise discretion to
select the appropriate setting given road
conditions, traffic, driver’s preferred driving
style and applicable laws and driving recom-
mendations for safe following distance.

273 Controls in detail
Driving systems
Increasing distance
Increasing the distance setting tells
Distronic to maintain a greater following
distance to the preceding vehicle.
Turn distance setting switch1 in
direction of arrow 3.
Decreasing distance
Decreasing the distance setting tells
Distronic to maintain a shorter following
distance to the preceding vehicle.
Turn distance setting switch1 in
direction of arrow 2.Driving with Distronic
This section describes a number of driving
situations where special precaution is re-
quired on the part of the driver. Be pre-
pared to brake in such situations. Braking
will deactivate the Distronic system.
Warning!G
Distronic works to maintain the speed
selected by the driver unless a moving
obstacle proceeding directly ahead of it in
the same travel direction is detected (e.g.
following another vehicle ahead of you at
your set distance). This means that:

Your vehicle can pass another vehicle
after you have changed lanes.

While in a sharp turn or if the preceding
vehicle is in a sharp turn, Distronic could
lose sight of the preceding vehicle. Your
vehicle could then accelerate to the
previously selected speed.
Distronic regulates only the distance be-
tween your vehicle and those directly ahead
of it, but does not register stationary objects
in the road, e.g.:

a stopped vehicle in a traffic jam

a disabled vehicle

an oncoming vehicle
The driver must always be alert, observe all
traffic and intercede as required by means
of steering or braking the vehicle.
Warning!G
Distronic should not be used in snowy or icy
road conditions.

274 Controls in detail
Driving systems
The most likely cause for a malfunctioning
system is a dirty sensor (located behind
the hood grille), especially at times of snow
and ice or heavy rain. In such a case,
Distronic will switch off, and the message
DISTRONIC Currently Unavailable See
Operator’s Manual
appears in the multi-
function display.
For cleaning and care of the Distronic sen-
sor, see “Cleaning the Distronic* system
sensor cover” (
page 407).Turns and bends
In turns or bends, Distronic may not detect
a moving vehicle in front, or it may detect
one too soon. This may cause your vehicle
to brake late or unexpectedly.Offset driving
A vehicle traveling in your lane but offset
from your direct line of travel may not be
detected by Distronic. There will be insuffi-
cient distance to the vehicle ahead.
iIf the message DISTRONIC Available
Again
appears during driving, the dirt (e.g.
slush) has dissolved; Distronic works again, if
you reactivate it (
page 268).

275 Controls in detail
Driving systems
Lane changing
Distronic has not yet detected the vehicle
changing lanes. There will be insufficient
distance to the lane-changing vehicle.Narrow vehicles
Because of their narrow profile, the vehi-
cles traveling near the outer edges of the
lane have not yet been detected by
Distronic. There will be insufficient
distance to the vehicles ahead.Distance warning function*
(Canada only)
When Distronic* is deactivated, this
function will continue to warn you when
recognizing a stationary obstacle or a
slower vehicle moving in your vehicle’s
path and the danger of a collision exists:

The distance warning lampl in the
instrument cluster comes on.

An intermittent warning will sound if
necessary.
If these warnings are issued, you must
brake manually to maintain a safe distance
and avoid a collision with the preceding
vehicle.
When pressing the brake pedal, the warn-
ing sound ceases. The warning sound will
also cease when the distance to the
preceding vehicle is sufficient again with-
out applying the brakes. In this case, the
distance warning lamp will also go out.

276 Controls in detail
Driving systems
Switch on the distance warning func-
tion in the control system
(
page 185).1Symbol for activated distance warning
function
When the distance warning function is
switched on, you will see the: symbol
in the Standard display. When the
distance warning function is deactivated
the:symbol will not appear.
AIRMATIC*
The AIRMATIC* consists of two compo-
nents:

Adaptive Damping System (ADS)*
(
page 276): Automatically optimizes
your vehicle’s suspension tuning.

Vehicle level control* (page 277):
Regulates the ride height of the vehicle.
Adaptive Damping System (ADS)*
The fine tuning of the damping is depen-
dent on:

road surface conditions

your driving style

your personal settings
The ADS switch is located on the upper
part of the center console.
Warning!G
If the distance warning lampl in the in-
strument cluster comes on while driving
and/or an intermittent warning sounds,
immediate attention on the part of the driver
is required. As required by the traffic
situation, apply the brakes and navigate
around a possible obstacle. However, do not
drive by relying on the distance warning
function, as this will result in an emergency
braking application. This will not always
enable you to avoid a collision, especially
when traveling on varying road surface
conditions and with varying driver reaction.
Complex driving situations are not always
fully recognized by the distance warning
function. This could result in wrong or miss-
ing distance warnings.

277 Controls in detail
Driving systems
1ADS switch
2Indicator lamp for SPORT setting
3Indicator lamp for COMF settingThe following settings are available:

AUTO (for normal driving situations)
Indicator lamps2 and3 are off.

SPORT (for sporty driving)
Indicator lamp2 comes on.

COMF (for comfort driving)
Indicator lamp3 comes on.
Start the engine (page 53).
Press ADS switch1 repeatedly until
the desired suspension tuning is
reached.Vehicle level control*
The vehicle level control automatically
regulates the ride height to

reduce fuel consumption

improve driving safety
The vehicle begins adjusting to the set
vehicle level as soon as the doors or
tailgate are

unlocked
or

opened or closed with the vehicle
unlocked
For major changes in vehicle level, the
engine must be running.
iThe setting is stored when you turn off the
engine.
iChanges to the vehicle level should be made
while the vehicle is moving. The vehicle will then
reach the set level as fast as possible.

278 Controls in detail
Driving systems
Basic settings
There are two settings from which to
choose:

Raised level, for driving on rough roads

Highway level, for driving on paved
roads in fair or better conditionThe vehicle’s ride height changes by the
approximate values given in table below
according to the set level:
The vehicle lowers to highspeed level
automatically when

the vehicles speed exceeds
70 mph (112 km/h)

the vehicles speed is between
60 mph (96 km/h) and
70 mph (112 km/h) for longer
than 20 seconds
Warning!G
Make sure that no one is near the wheel
housing or under the vehicle when you lower
the vehicle while it is standing still. Limbs
could become wedged into or under the
vehicle.
For safety reasons, the vehicle can only be
lowered with all doors and the tailgate
closed. Lowering is interrupted if a door or
the tailgate is opened and will continue after
the door is closed again.
Warning!G
Adapt your speed and driving to possible
changed driving behavior of the vehicle after
changing the vehicle level. The ESP
® cannot
prevent accidents, including those resulting
from excessive speed. The ESP
® cannot
prevent the natural laws of physics from
acting on the vehicle.
!Keep in mind that in rough or uneven roads,
adjusting the vehicle to a lower level may cause
the vehicle underbody to come in contact with
the road and result in damage to the vehicle un-
derbody. Always make sure the vehicle has suffi-
cient ground clearance before adjusting it to a
lower level.
!Before jacking up the vehicle with equip-
ment that lifts one or more of the wheels com-
pletely off the ground, remove the SmartKey
from the starter switch.
!Please also note the information in the
section on towing (
page 513).
iThe activation threshold is defined by the set
suspension tuning (
page 276).
iThe third available level is the highspeed
level that is set automatically.
LevelRide height
Raised+ 1.97 in (+ 50 mm)
Highway+/- 0
Highspeed- 0.78 in (- 20 mm)
iObey local speed limits. Use prudent driving
speeds appropriate to prevailing conditions.

279 Controls in detail
Driving systems
Raised level
Only choose the raised level when the road
conditions permit. Otherwise:

Fuel consumption may increase.

Handling characteristics of the vehicle
may be unfavorable.
Start the engine (page 53).The switch is located on the upper part of
the center console.
1Vehicle level control switch
2Indicator lamp
If indicator lamp2 is off:
Press switch1.
Indicator lamp2 flashes. The vehicle
adjusts to the raised level.
The following message appears in the
multifunction display while the level is
being set:When the raised level is reached, indicator
lamp2 comes on continuously and the
following message appears in the multi-
function display:
iYou can select the raised level at vehicle
speeds of up to 25 mph (40 km/h). At a higher
vehicle speed, the message
n
Level Selection Not Permitted
appears in the multifunction display.
iThe messages can be cleared by pressing
buttonæ orç on the multifunction steer-
ing wheel.