MERCEDES-BENZ R320 2008 W251 Owner's Manual

280 Controls in detail
Driving systems
Highway level
Close all doors and the tailgate.
Start the engine (page 53).
The switch is located on the upper part of
the center console.
1Vehicle level control switch
2Indicator lampIf indicator lamp2 is on:
Press switch1.
Indicator lamp2 flashes. The vehicle
adjusts to the highway level.
The following message appears in the
multifunction display while the level is
being set:When the highway level is reached, indica-
tor lamp2 goes out and the following
message appears in the multifunction dis-
play:
!Keep in mind that on 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
underbody. Always make sure the vehicle has
sufficient ground clearance before adjusting it
to a lower level.
iThe messages can be cleared by pressing
buttonæ orç on the multifunction steer-
ing wheel.
iThe vehicle level is set to highway level auto-
matically when the vehicle speed is exceeding
25 mph (40 km/h).

281 Controls in detail
Driving systems
Permanent four-wheel drive (4MATIC)*
Your vehicle is equipped with permanent
four-wheel drive (4MATIC). Both, the front
and rear axles, are powered at all times
when the vehicle is being operated. The
4MATIC improves traction in conjunction
with the ESP
® (page 101) and the
Electronic Traction System (
page 103).
Parktronic* (Parking assist)
Warning!G
If a drive wheel is spinning due to insuffi-
cient traction:

While driving off, apply as little throttle
as possible.

While driving, ease up on the accelera-
tor.

Adapt your speed and driving style to
the prevailing road conditions.
Failure to observe these guidelines could
cause the vehicle to skid.
The 4MATIC cannot prevent accidents re-
sulting from excessive speed.
!Operational or performance test must only
be conducted on a two-axle dynamometer. If
such tests are necessary, contact an authorized
Mercedes-Benz Light Truck Center. You could
otherwise seriously damage the brake system or
the transfer case which is not covered by the
Mercedes-Benz Limited Warranty.
!Because the ESP® operates automatically,
the engine and ignition must be shut off
(SmartKey in starter switch position0 or1 or
KEYLESS-GO* start/stop button in
position0or1) when testing the parking brake
on a brake test dynamometer and such testing
should be no longer than 10 seconds.
Active braking action through the ESP
® may
otherwise seriously damage the brake system
which is not covered by the Mercedes-Benz
Limited Warranty.
iIn winter operation, the maximum effective-
ness of the 4MATIC is only achieved with winter
tires (
page 398) or snow chains as required.
Warning!G
Parktronic is a supplemental system. It is
not intended to, nor does it replace, the
need for extreme care. The responsibility
during parking and other critical maneuvers
always remains with the driver.
Special attention must be paid to objects
with smooth surfaces or low silhouettes
(e.g. trailer couplings, painted posts, or road
curbs). Such objects may not be detected by
the system and can damage the vehicle.
The operational function of the Parktronic
system can be affected by dirty sensors,
especially at times of snow and ice, see
“Cleaning the Parktronic* system sensors”
(
page 408).
Interference caused by other ultrasonic
signals (e.g. working jackhammers, car
wash, or the air brakes of trucks) can cause
the system to send erratic indications, and
should be taken into consideration.

282 Controls in detail
Driving systems
The Parktronic system is an electronic aid
designed to assist the driver during
parking maneuvers. It visually and audibly
indicates the relative distance between the
vehicle and an obstacle.
The Parktronic system is automatically
activated when you

switch on the ignition or start the
engine
and

release the parking brake
and

set the automatic transmission to
positionD,R, orNThe Parktronic system deactivates at
vehicle speeds exceeding approximately
11 mph (18 km/h). At lower vehicle
speeds, the Parktronic system turns on
again.
The Parktronic system also deactivates
when you set the automatic transmission
to positionP or depress the parking brake
pedal.
The Parktronic system monitors the
surroundings of your vehicle with six sen-
sors in the front bumper and four sensors
in the rear bumper.
1Sensors in the front bumperRange of the sensors
To function properly, the sensors must be
free of dirt, ice, snow and slush. Clean the
sensors regularly, being careful not to
scratch or damaging the sensors, see
“Cleaning the Parktronic* system sensors”
(
page 408).
Warning!G
Make sure no persons or animals are in the
area in which you are maneuvering. You
could otherwise injure them.
!During parking maneuvers, pay special
attention to objects located above or below the
height of the sensors (e.g. planters or trailer
hitches).
The Parktronic system will not detect such
objects at close range and damage to your
vehicle or the object may result.
Ultrasonic signals from outside sources (e.g.
working jackhammers, car wash or the air brakes
of trucks) may impair the operation of the
Parktronic system.

283 Controls in detail
Driving systems
Front sensors
Rear sensors
Minimum distance
If the system detects an obstacle in this
range, all the distance warning segments
illuminate and you hear a warning signal. If
the obstacle is closer than the minimum
distance, the actual distance may no
longer be indicated by the system.Warning indicators
Visual signals indicate to the driver the
relative distance between the sensors and
an obstacle. The warning indicator for the
front area is located above the center air
vents in the dashboard. The warning indi-
cator for the rear area is located in the rear
overhead control panel.
Front area warning indicator
1Left side of the vehicle
2Right side of the vehicle
3Readiness indicators
Centerapprox. 40 in (100 cm)
Cornersapprox. 24 in (60 cm)
Centerapprox. 48 in (120 cm)
Cornersapprox. 32 in (80 cm)
Centerapprox. 8 in (20 cm)
Cornersapprox. 6 in (15 cm)

284 Controls in detail
Driving systems
Each warning indicator is divided into five
yellow and two red distance segments for
either side of the vehicle. The Parktronic
system is ready when the yellow readiness
indicators3 are illuminated.
The current transmission position deter-
mines which warning indicator will be
activated.As your vehicle approaches an object, one
or more distance segments will illuminate,
depending on the distance. When the
seventh distance segment illuminates, you
have reached the minimum distance.

Front area: An intermittent acoustic
warning lasting a maximum of
2 seconds will sound as the first red
distance segment illuminates and a
constant acoustic warning lasting a
maximum of 2 seconds will sound for
the second red distance segment. The
signal is canceled when the automatic
transmission is set to positionP or the
parking brake is set.

Rear area: An intermittent acoustic
warning lasting a maximum of
2 seconds will sound as the first red
distance segment illuminates and a
constant acoustic warning lasting a
maximum of 2 seconds will sound for
the second red distance segment. The
signal is canceled when the automatic
transmission is set to positionD, P, or
the parking brake is set.Switching the Parktronic system
on/off
You can switch off the Parktronic system
manually.
The Parktronic switch is located in the
upper part of the center console.
1Parktronic switch
2Indicator lamp
Switching off
Press Parktronic switch1.
Indicator lamp2 comes on.
Transmission
positionWarning indicator
DFront area activated
R or NFront and rear area
activated
PNeither activated

285 Controls in detail
Driving systems
Switching on
Press Parktronic switch1 once more.
Indicator lamp2 goes out.
Parktronic system malfunction
If only the red distance segments illumi-
nate and an acoustic warning sounds,
there is a malfunction in the Parktronic
system. The Parktronic system will auto-
matically switch off after 20 seconds and
the indicator lamp in the Parktronic switch
comes on.
Have the Parktronic system checked
by an authorized Mercedes-Benz Light
Truck Center as soon as possible.If only the red distance segments illumi-
nate and no acoustic warning sounds, the
Parktronic system sensors are dirty (e.g.
slush, snow or ice) or there is an interfer-
ence from other radio or ultrasonic signals
(e.g. working jackhammers, car wash or
the air brakes of trucks). The Parktronic
system will automatically switch off after
20 seconds and the indicator lamp in the
Parktronic switch comes on.
Switch off the ignition (page 39).
Clean the Parktronic system sensors
(
page 408).
Switch on the ignition (page 39).
or
Check the Parktronic system operation
at another location to rule out interfer-
ence from outside radio or ultrasonic
signals.
Rear view camera*
iThe Parktronic system switches on
automatically when you switch on the ignition
(
page 39).
Warning!G
The rear view camera is only an aid and may
display obstacles from a distorted perspec-
tive or inaccurately, or may not display ob-
stacles at all. The rear view camera does not
relieve you of the responsibility to be cau-
tious, take care and pay careful attention.
The rear view camera may not show objects
which are

very close to the rear bumper

under the rear bumper

above the tailgate handle
You are responsible for safety at all times
and must continue to pay attention to the
immediate surroundings when parking and
maneuvering. This includes the area behind,
in front of and beside the vehicle. Otherwise
you could endanger yourself or others.

286 Controls in detail
Driving systems
The rear view camera is an optical parking
aid. It shows you the area behind the vehi-
cle in the COMAND system display when
reverse gear R is engaged, for example
during parallel parking.
The rear view camera is located near the
tailgate handle.
1Rear view camera
Warning!G
Make sure that no persons or animals are in
or near the area in which you are
parking/maneuvering. Otherwise, they
could be injured.
Warning!G
The rear view camera either will not function
or will not function to its full capability if

the tailgate is open

it is raining very hard, snowing or foggy

it is night or you are parking/maneuver-
ing your vehicle in an area where it is
very dark

the camera is exposed to a very bright
white light

the immediate surroundings are illumi-
nated with fluorescent light (the display
may flicker)

there is a sudden change in tempera-
ture, e.g. if you drive into a heated
garage from the cold (lens condensa-
tion)

the camera lens is dirty or covered

the rear of your vehicle is damaged
In this case, have the position and set-
ting of the camera checked by a quali-
fied specialist workshop.
Mercedes-Benz recommends that you
contact a Mercedes-Benz Light Truck
Center for this purpose.
Do not use the rear view camera in these sit-
uations. Otherwise you could injure yourself
or others and/or damage property including
your vehicle while parking/maneuvering.

287 Controls in detail
Driving systems
Switching the rear view camera
on and off
Switch on the ignition (page 39).
Shift the automatic transmission to
positionR (
page 190).
The area behind the vehicle appears in
the COMAND system display.
Shift the automatic transmission to
positionP,N orD to switch off the rear
view camera.
iThe area behind the vehicle is shown in the
COMAND system display as a mirror image, like
in the rear view mirror.
iThe image from the rear view camera will
no longer be displayed if you select another
function on the COMAND system while reverse
gear R is engaged. To display the image again,
disengage and reengage reverse gear R.

288 Controls in detail
Loading
Roof rack*
1Trim coverFlip roof trim covers 1 open.
Attach the roof rack to the attachment
points under roof trim covers 1.
Follow roof rack manufacturer’s
installation instructions.
For further information, inquire at your
Mercedes-Benz Light Truck Center.
Warning!G
Only use the roof rack when the basic
carrier bars have been completely mounted.
The left and right roof rails are only
stabilized by means of the basic carriers
being mounted.
Follow the manufacturer’s installation
instructions. Otherwise, an improperly
attached roof rack system or its load could
become detached from the vehicle.
Do not exceed the maximum roof load of
220 lb (100 kg).
Take into consideration that when the roof
rack is loaded, the handling characteristics
are different from those when operating the
vehicles without the roof rack loaded.
!Load the roof rack in such a way that the
vehicle cannot be damaged while driving.
Make sure

you can completely raise the tilt/sliding
sunroof* (or tilt/sliding panel*) at the rear

you can open the tilt/sliding sunroof* (or
tilt/sliding panel*) completely

you can open the tailgate completely

289 Controls in detail
Loading
Loading instructions
Load distribution
The gross vehicle weight which is the
weight of the vehicle including fuel, tools,
spare wheel, installed accessories, pas-
sengers, and luggage/cargo must never
exceed the load limit and the Gross Vehicle
Weight Rating (GVWR) for your vehicle as
specified on the placard located on the
driver’s door B-pillar (
page 524). In addi-
tion, the load must be distributed in such a
way so that the weight on each axle never
exceeds the Gross Axle Weight Rating
(GAWR) for the front and rear axle. The
GVWR and GAWR for your vehicle are indi-
cated on the certification label which can
be found on the driver’s door B-pillar
(
page 524).
For more information, see “Tire and Load-
ing Information” (
page 367).
The handling characteristics of a fully
loaded vehicle depend greatly on the load
distribution. It is therefore recommended
to load the vehicle according to the illustra-
tions shown, with the heaviest items being
placed towards the front of the vehicle.
Warning!G
Always fasten items being carried as
securely as possible using cargo tie-down
rings and fastening materials appropriate
for the weight and size of the load.
In an accident, during hard braking or
sudden maneuvers, loose items will be
thrown around inside the vehicle, and can
cause injury to vehicle occupants unless the
items are securely fastened in the vehicle.
To help avoid personal injury during a
collision or sudden maneuver, always use
tie-down rings and, if so equipped, always
use the cargo net* when transporting cargo.
Never drive vehicle with the tailgate open.
Deadly carbon monoxide (CO) gases may
enter vehicle interior resulting in uncon-
sciousness and death.