2008 MERCEDES-BENZ R320 warning

263 Controls in detail
Driving systems
Warning!G
Distronic is a convenience system. Its speed
adjustment reduction capability is intended
to make cruise control more effective and
usable when traffic speeds vary. It is not
however, intended to, nor does it, replace
the need for extreme care.
The responsibility for the vehicle’s speed,
distance to the preceding vehicle and, most
importantly, brake operation to ensure a
safe stopping distance, always remains with
the driver.
Distronic cannot take road and traffic condi-
tions into account.
Complex driving situations are not always
fully recognized by Distronic. This could
result in wrong or missing distance
warnings.
Warning!G
Distronic adaptive cruise control is no
substitute for active driving involvement. It
does not react to pedestrians or on station-
ary objects, nor does it recognize or predict
the lane curvature or the movement of
preceding vehicles.
Distronic can only apply a maximum of 20%
of the vehicle’s braking power.
It is the driver’s responsibility at all times to
be attentive to the road, weather and traffic
conditions. Additionally, the driver must
provide the steering, braking and other
driving inputs necessary to remain in control
of the vehicle.
High-frequency sources such as toll
stations, speed measuring systems etc. can
cause the Distronic system to malfunction.
Warning!G
Distronic requires familiarity with its opera-
tional characteristics. We strongly recom-
mend that you review the following
information carefully before operating the
system.
Warning!G
Distronic cannot take road and traffic condi-
tions into account. Only use Distronic if the
road, weather and traffic conditions make it
advisable to travel at a constant speed.
Warning!G
Use of Distronic can be dangerous on slip-
pery roads. Rapid changes in tire traction
can result in wheel spin and loss of control.


264 Controls in detail
Driving systems
Distronic does not act upon adverse sight
and distance conditions. Do not use
Distronic during conditions of fog, heavy
rain, snow or sleet.
Warning!G
Distronic cannot take weather conditions
into account. Switch off Distronic or do not
switch it on if:

roads are slippery or covered with snow
or ice. The wheels could lose traction
while braking or accelerating, and the
vehicle could skid.

the sensor is dirty or visibility is
diminished due to snow, rain or fog, for
example. The distance control system
functionality could be impaired.
Always pay attention to surrounding traffic
conditions even while Distronic is switched
on. Otherwise, you may not be able to recog-
nize dangerous situations until it is too late.
This could cause an accident in which you
and others could be injured.
Warning!G
The “Resume” function should only be
operated if the driver is fully aware of the
previously set speed and wishes to resume
this particular preset speed.
Warning!G
Close attention to road and traffic condi-
tions is imperative at all times, regardless of
whether or not Distronic is activated.
Use of Distronic can be dangerous on
winding roads or in heavy traffic because
conditions do not allow safe driving at a
continuous speed.
Distronic will not react to stationary objects
in the roadway (e.g. a stopped vehicle in a
traffic jam or a disabled vehicle). Distronic
will also not respond to oncoming vehicles.
Switch off Distronic:

when changing from the left to the right
lane if vehicles are moving more slowly
in the left lane

when entering a turn lane or highway off
ramp

in complex driving situations, such as in
highway construction zones
In these situations, Distronic will continue to
maintain the set speed unless deactivated.
Distronic is designed and intended only to
maintain a set speed and keep a set dis-
tance from moving objects in front of it.


266 Controls in detail
Driving systems
If Distronic calculates that there is a dan-
ger of collision:

The distance warning lampl in the
instrument cluster comes on
(
page 26).

An intermittent warning sounds.
Immediately apply the brake to avoid a
collision.
Under no circumstances should the
driver await the intermittent warning
sound before braking. See the follow-
ing warning note.
The intermittent warning sound ceases
and the distance warning lampl
goes out when the necessary distance
to the vehicle ahead is again estab-
lished.
Warning!G
An intermittent warning sounds and the
distance warning lampl in the instru-
ment cluster is illuminated if the Distronic
system calculates that the distance to the
vehicle ahead and your vehicle’s current
speed indicate that Distronic will not be ca-
pable of slowing the vehicle sufficiently to
maintain the preset following distance,
which creates a danger of a collision.
Immediately brake the vehicle to increase
your distance to the preceding vehicle. The
warning sound is intended as a final caution
in which you should intercede with your own
braking inputs to avoid a potentially danger-
ous situation. Do not wait for the operation
of the warning signal to intercede with your
own braking. This will result in potentially
dangerous emergency braking which will
not always result in an impact being
avoided.
Tailgating increases the risk of an accident.
Warning!G
Distronic brakes your vehicle with a maxi-
mum deceleration of 6.5 ft/s2 (2 m/s2). This
corresponds to about 20% of the maximum
deceleration of your vehicle.
Distronic brakes the vehicle in an effort to
restore the preset distance or to maintain
the set speed.
Keep driver’s foot area clear at all times, in-
cluding the area under the brake pedal. Ob-
jects stored in this area may impair pedal
movement which could interfere with the
braking ability of the Distronic system.
Do not place your foot under the brake pedal
– your foot could become caught.

267 Controls in detail
Driving systems
Distronic menu in the control system
Use the
DISTRONIC menu to display the
current settings for your Distronic system.
The information shown in the multifunction
display depends on whether the Distronic
system is activated or deactivated.
Press buttonè orÿ repeatedly
until one of the following two displays
appears in the multifunction display.Distronic activated
When you turn Distronic on, you will see
the set speed in the multifunction display
for about 5 seconds. When Distronic is
activated, the following display appears in
the multifunction display.
1Distronic activated
2Set vehicle speedDistronic deactivated
When Distronic is deactivated, you will see
the standard Distronic display in the multi-
function display.
1Preceding vehicle, if detected
2Actual distance to the preceding
vehicle
3Preset distance threshold to the
preceding vehicle
4Your vehicle
Cruise control lever
The Distronic system is operated by means
of the cruise control lever.
The cruise control lever is the uppermost
lever on the left-hand side of the steering
column.
iFor activating or deactivating the Distronic
system, see “Activating Distronic” (
page 268)
or see “Deactivating Distronic” (
page 271).
For activating or deactivating the Distance warn-
ing function, see “Distance warning function*”
(
page 185).

269 Controls in detail
Driving systems
Setting a higher speedYou can increase the set speed in two
ways.
Adjustment in 1 mph (Canada: 1 km/h)
incrementsBriefly lift the cruise control lever up to
the resistance point in direction of
arrow1 (
page 268).
Release the cruise control lever.
The vehicle set speed increases in in-
crements of 1 mph (Canada: 1 km/h).Adjustment in 5 mph
(Canada: 10 km/h) increments
Briefly lift the cruise control lever up
past the resistance point in direction of
arrow1 (
page 268).
Release the cruise control lever.
The vehicle set speed increases in
increments of 5 mph
(Canada: 10 km/h).
iIf you do not take your foot off of the accel-
erator pedal but continue to accelerate past the
set speed, the following message will appear in
the multifunction display:
DISTRONIC Override
The distance to a slower moving vehicle in front
of you will not be set. Your vehicle speed will
then be determined only by the accelerator
pedal position.
Warning!G
If you increase the set vehicle speed, keep in
mind that it may take a brief moment until
the vehicle has reached the set speed.
Increase 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.
iThe set speed value is increased in 1 mph
(Canada: 1 km/h) increments each time you lift
the cruise control lever up to the resistance
point.
iThe set speed value is increased in 5 mph
(Canada: 10 km/h) increments each time you lift
the cruise control lever up past the resistance
point.
iThe new speed is set and the vehicle will
accelerate. Keep in mind that it may take a brief
moment until the vehicle has reached the set
speed.

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.