engine MERCEDES-BENZ R320 2008 W251 Manual Online

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.

311 Controls in detail
Useful features
Cupholders in third-row side trim
Cupholders are located in the side trims of
the third-row seats.
1Cup holderAshtrays
Your vehicle is equipped with an ashtray
and a cigarette lighter (
page 313)
located in the front center console and an
ashtray located in front of the second-row
seats (
page 312).
Ashtray in the front center console
Opening the ashtray
1Cover
2Chrome label
Tab lightly on chrome label 2 of
cover1.
Cover 1 swings open.
Removing ashtray insert
Warning!G
Remove ashtray insert only with vehicle
standing still. Set the parking brake to
secure vehicle from movement. Set auto-
matic transmission toP. With the automatic
transmission set toP, turn off the engine.

314 Controls in detail
Useful features
Power outletsPower outlets are located

in the front passenger footwell
(
page 314)

in the second-row footwell
(
page 315)

on the right-hand side of the cargo
compartment (
page 315)
Power outlet in front passenger
footwell
Switch on the ignition (page 39).
Flip up cover and insert electrical plug
(cigarette lighter type).
!The lighter socket can accommodate 12V
DC electrical accessories (up to a maximum of
85 W) designed for use with the standard “ciga-
rette lighter” plug type. Keep in mind, however,
that connecting accessories to the lighter socket
(for example extensive connecting and discon-
necting, or using plugs that do not fit properly)
can damage the lighter socket. With the socket
damaged, the lighter may no longer be able to be
placed in the heating (pushed-in) position, or the
lighter may pop out too early with the lighter not
hot enough.
To help avoid damaging the cigarette lighter
socket, we recommend connecting 12V DC elec-
trical accessories designed for use with the stan-
dard “cigarette lighter” plug type to the
12V power outlets (
page 314) in your vehicle
whenever possible.
!The cigarette lighter is not designed for use
with the electric air pump (
page 499). Use a
power outlet (
page 314) for electric air pump
operation.
iIf the engine is off, and the cigarette lighter
is being used extensively, the vehicle battery
may become discharged.
!If you use all power outlets in the vehicle,
make sure that the maximum current drawn
does not exceed 55 A.
iThe power outlets can be used to
accommodate 12V DC electrical accessories
(e.g. air pump, auxiliary lamps) up to a maximum
of 240 W.
If the engine is off and the power outlets are
being used extensively, the vehicle battery may
become discharged.
iYou can use the power outlets, except for
the power outlet in the front center console,
even if the ignition is switched off.
An emergency shut-off feature ensures that the
vehicle’s electrical voltage does not fall below a
minimum level. If the voltage drops to this mini-
mum level, the power outlets are automatically
switched off. This ensures that enough power
remains to start the engine.

319 Controls in detail
Useful features
Telephone*
Radio transmitters, such as a portable tele-
phone or a citizens band unit, should only
be used inside the vehicle if they are con-
nected to an antenna that is installed on
the outside of the vehicle.
The external antenna must be approved by
Mercedes-Benz. Please contact an autho-
rized Mercedes-Benz Light Truck Center
for information on the installation of an
approved external antenna. Refer to the
radio transmitter operation instructions
regarding use of an external antenna.When the mobile phone is inserted in the
cradle, you can operate the telephone
using the following devices:

mobile phone keypad

COMAND system (see separate operat-
ing instructions)

buttonss andt on the multi-
function steering wheel (
page 158)

Voice Control System* (see separate
operating instructions)
Warning!G
Never operate radio transmitters equipped
with a built-in or attached antenna (i.e. with-
out being connected to an external antenna)
from inside the vehicle while the engine is
running. Doing so could lead to a malfunc-
tion of the vehicle’s electronic system,
possibly resulting in an accident and/or
serious personal injury.
Warning!G
Please do not forget that your primary
responsibility is to drive the vehicle.
A driver’s attention to the road must always
be his/her primary focus when driving. For
your safety and the safety of others, we
recommend that you pull over to a safe loca-
tion and stop before placing or taking a
telephone call.
If you choose to use the telephone
1 while
driving, please use the hands-free device
and only use the telephone when road,
weather and traffic conditions permit. Some
jurisdictions prohibit the driver from using a
mobile telephone while driving a vehicle.
Only operate the COMAND system
1 if road,
weather and traffic conditions permit.
Bear in mind that at a speed of just
30 mph (approximately 50 km/h), your
vehicle is covering a distance of 44 feet
(approximately 14 m) every second.
1Observe all legal requirements.
iVarious mobile phone cradles can be
installed in the front center armrest, see
separate installation instructions for the mobile
phone cradle. These mobile phone cradles can
be obtained from an authorized Mercedes-Benz
Light Truck Center.
The functions and services available to you while
using the mobile phone depend on your service
provider and the type of mobile phone you are
using. See also separate operating manual for
instructions on how to use the mobile phone.

330 Controls in detail
Useful features
Programming the integrated remote
control
Step 1:
Switch on the ignition (page 39).Step 2:
If you have previously programmed a
signal transmitter button and wish to
retain its programming, proceed to
step 3.
If you are programming the integrated
remote control for the first time,
press and hold the two outer signal
transmitter buttons2 and4 and
release them only when indicator
lamp1 begins to flash after approxi-
mately 20 seconds (do not hold the
button for longer than 30 seconds).
This procedure erases any previous
settings for all three channels and ini-
tializes the memory.
If you later wish to program a second
and/or third hand-held transmitter to
the remaining two signal transmitter
buttons, do not repeat this step and
begin directly with step 3.Warning!G
Before programming the integrated remote
control to a garage door opener or gate
operator, make sure people and objects are
out of the way of the device to prevent po-
tential harm or damage. When programming
a garage door opener, the door moves up or
down. When programming a gate operator,
the gate opens or closes.
Do not use the integrated remote control
with any garage door opener that lacks
safety stop and reverse features as required
by U.S. federal safety standards (this
includes any garage door opener model
manufactured before April 1, 1982).
A garage door that cannot detect an object
– signaling the door to stop and reverse –
does not meet current U.S. federal safety
standards.
When programming a garage door opener,
park the vehicle outside the garage.
Do not run the engine while programming
the integrated remote control. Inhalation of
exhaust gas is hazardous to your health. All
exhaust gas contains carbon monoxide
(CO), and inhaling it can cause unconscious-
ness and possible death.

337 Operation
The first 1 000 miles (1 500 km)
Driving instructions
At the gas station
Engine compartment
Tires and wheels
Winter driving
Maintenance
Vehicle care

338 Operation
In the “Operation” section you will find
detailed information on operating, main-
taining and caring for your vehicle.
The first 1 000 miles (1 500 km)
The more cautiously you treat your vehicle
during the break-in period, the more satis-
fied you will be with its performance later
on.

Drive your vehicle during the first
1 000 miles (1 500 km) at varying but
moderate vehicle and engine speeds.

During this period, avoid heavy loads
(full throttle driving) and excessive
engine speeds (no more than
2/3 of
maximum rpm in each gear).

Shift gears in a timely manner.

Avoid accelerating by kick-down.

Do not attempt to slow the vehicle
down by shifting to a lower gear using
the gear selector lever.

Select gear3, 2 or1 (page 199) only
when driving at moderate speeds (for
hill driving).

SelectCas the preferred shift
program (
page 200) for the first
1 000 miles (1 500 km).After 1 000 miles (1 500 km) you may
gradually increase vehicle and engine
speeds to the permissible maximum.
All of the above instructions, as may apply
to your vehicle type, also apply when
driving the first 1 000 miles (1 500 km) af-
ter the engine, the transfer case, the front
differential or the rear differential has been
replaced.
iAlways obey applicable speed limits.

339 Operation
Driving instructions
Driving instructions
Drive sensibly – save fuel
Fuel consumption, to a great extent,
depends on driving habits and operating
conditions.
To save fuel you should:

Keep tires at the recommended
inflation pressures.

Remove unnecessary loads.

Remove carriers when not in use.

Allow engine to warm up under low
load use.

Avoid frequent acceleration and
deceleration.

Have all maintenance work performed
at the intervals specified in the
Maintenance Booklet and as required
by the Maintenance System. Contact
an authorized Mercedes-Benz Light
Truck Center.
Fuel consumption is also increased by
driving in cold weather, in stop-and-go
traffic, on short trips and in hilly area.
Drinking and drivingPedals
Warning!G
Drinking and driving and/or taking drugs
and driving are a very dangerous combina-
tion. Even a small amount of alcohol or
drugs can affect your reflexes, perceptions
and judgment.
The possibility of a serious or even fatal
accident are greatly increased when you
drink or take drugs and drive.
Do not drink or take drugs and drive or allow
anyone to drive who has been drinking or
taking drugs.
Warning!G
Make sure that absolutely no objects are ob-
structing the pedal’s range of movement.
Keep the driver’s footwell clear of all obsta-
cles. If there are any floormats or carpets in
the footwell, make sure the pedals still have
sufficient clearance.
During sudden driving or braking maneu-
vers, the objects could get caught between
the pedals. You could then no longer brake
or accelerate. This could lead to accidents
and injury.

340 Operation
Driving instructions
Power assistanceBrakes
Warning!G
With the engine not running, there is no
power assistance for the brake and steering
systems. In this case, it is important to keep
in mind that a considerably higher degree of
effort is necessary to brake and steer the ve-
hicle.
Warning!G
After driving in heavy rain for some time
without applying the brakes or through wa-
ter deep enough to wet brake components,
the first braking action may be somewhat
reduced and increased pedal pressure may
be necessary to obtain expected braking
effect. Maintain a safe distance from
vehicles in front.
Resting your foot on the brake pedal will
cause excessive and premature wear of the
brake pads.
It can also result in the brakes overheating,
thereby significantly reducing their effec-
tiveness. It may not be possible to stop the
vehicle in sufficient time to avoid an
accident.
!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 the vehicle is being towed
with one axle raised.
Active braking action through the ESP
® may
otherwise seriously damage the brake system
which is not covered by the Mercedes-Benz
Limited Warranty
!Vehicles with 4MATIC must not be towed
with one axle raised.
!Vehicles with 4MATIC:
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.

341 Operation
Driving instructions
To help prevent brake disk corrosion after
driving on wet road surfaces (particularly
salted roads), it is advisable to brake the
vehicle with considerable force prior to
parking. The heat generated serves to dry
the brakes.
If your brake system is normally only
subjected to moderate loads, you should
occasionally test the effectiveness of the
brakes by applying above-normal braking
pressure at higher speeds. This will also
enhance the grip of the brake pads.Refer to the description of the Brake Assist
System (BAS) (
page 101).
Brake pad wear or a leak in the system may
be the reason for low brake fluid level in
the reservoir.
The brake fluid level in the reservoir may
be too low if the brake warning lamp
in the instrument cluster comes on and an
acoustic warning sounds although the
parking brake is released (
page 415).
Observe additional messages in the multi-
function display that may appear
(
page 447).
Have the brake system inspected
immediately. Contact an authorized
Mercedes-Benz Light Truck Center.All checks and service work on the brake
system should be carried out by qualified
technicians only. Contact an authorized
Mercedes-Benz Light Truck Center.
Only install brake pads and brake fluid
recommended by Mercedes-Benz.
!Vehicles with 4MATIC:
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 test-
ing the parking brake on a brake test dynamom-
eter 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.
Warning!G
Make sure not to endanger any other road
users when carrying out these braking
maneuvers.
Warning!G
If other than recommended brake pads are
installed, or other than recommended brake
fluid is used, the braking properties of the
vehicle can be degraded to an extent that
safe braking is substantially impaired. This
could result in an accident.