2008 MERCEDES-BENZ ML320 Engine light

287 Controls in detail
Useful features
Switch on the ignition (page 40).
1Cigarette lighter
Open the ashtray (page 285).
Push in cigarette lighter1.
The cigarette lighter will pop out auto-
matically when hot.
Power outlets!The lighter socket can accommodate
12V DC electrical accessories (up to a maximum
of 180 W) designed for use with the standard
“cigarette lighter” plug type. Keep in mind, how-
ever, that connecting accessories to the lighter
socket (for example extensive connecting and
disconnecting, or using plugs that do not fit prop-
erly) can damage the lighter socket. With the
socket damaged, the lighter may no longer be
able to be placed in the heating (pushed-in) posi-
tion, 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 287) in your vehicle
whenever possible.
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, the battery may become dis-
charged if used for long periods of time.
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 re-
mains to start the engine.

291 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 ap-
proved external antenna. Refer to the radio
transmitter operation instructions regard-
ing use of an external antenna.When the mobile phone is inserted in the
cradle, you can operate the telephone us-
ing the following devices:

mobile phone keypad

COMAND system (see separate operat-
ing instructions)

buttonss andt on the multi-
function steering wheel (
page 148)

Voice Control System* (see separate
operating instructions)
Please note that these functions are only
available with Mercedes-Benz approved
mobile phones.
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, pos-
sibly resulting in an accident and/or serious
personal injury.
Warning!G
Please do not forget that your primary re-
sponsibility 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 rec-
ommend that you pull over to a safe location
and stop before placing or taking a tele-
phone 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
cellular 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 (approximate-
ly 14 m) every second.
1Observe all legal requirements.
iVarious mobile phone cradles can be in-
stalled in the front center armrest, see separate
installation instructions for the mobile phone
cradle. These mobile phone cradles can be ob-
tained 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 in-
structions on how to use your mobile phone.

311 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 infla-
tion pressures.

Remove unnecessary loads.

Remove carriers* when not in use.

Allow engine to warm up under low
load use.

Avoid frequent acceleration and decel-
eration.

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 driv-
ing in cold weather, in stop-and-go traffic,
on short trips and in hilly areas.
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 that 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.

312 Operation
Driving instructions
Power assistance
BrakesTo 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 sub-
jected to moderate loads, you should occa-
sionally 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.
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 re-
duced and increased pedal pressure may be
necessary to obtain expected braking ef-
fect. 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 acci-
dent.
!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.

313 Operation
Driving instructions
Refer to the description of the Brake Assist
System (BAS) (
page 100).
Brake pad wear or a leak in the system may
be the reason for low brake fluid 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 401).
Observe additional messages in the multi-
function display that may appear
(
page 430).
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.
After hard braking, it is advisable to drive
on for some time, rather than immediately
park, so that the air stream will cool down
the brakes faster.
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.
!When driving down long and steep grades,
relieve the load on the brakes by shifting into a
lower gear to use the engine’s braking power.
This helps prevent overheating of the brakes and
reduces brake pad wear.
When using the engine’s braking power, a drive
wheel may not spin for an extended period of
time, e.g. on slippery road surfaces. This may
cause serious damage to the drivetrain which is
not covered by the Mercedes-Benz Limited
Warranty.

318 Operation
Driving instructions
Winter driving instructions
The most important rule for slippery or icy
roads is to drive sensibly and to avoid
abrupt acceleration, braking and steering
maneuvers. Do not use the cruise control
system under such conditions.
When the vehicle is in danger of skidding,
shift the automatic transmission to
positionN. Try to keep the vehicle under
control by corrective steering action.Road salts and chemicals can adversely af-
fect braking efficiency. Increased pedal
force may become necessary to produce
the normal brake effect.
Depressing the brake pedal periodically
when traveling at length on salt-strewn
roads can bring road-salt-impaired braking
efficiency back to normal.
If the vehicle is parked after being driven
on salt-treated roads, the braking efficien-
cy should be tested as soon as possible af-
ter driving is resumed.
iFor information on speed ratings for winter
tires, see “Winter tires” (
page 384).
For additional general information on tire speed
markings on the tire sidewall, see “Tire speed
rating” (
page 382).
iFor information on driving with snow chains,
see “Snow chains” (
page 385).
Warning!G
On slippery road surfaces, never downshift
in order to obtain braking action. This could
result in drive wheel slip and reduced vehi-
cle control. Your vehicle’s ABS will not pre-
vent this type of control loss.
Warning!G
Make sure not to endanger any other road
users when carrying out these braking
maneuvers.
Warning!G
If the vehicle becomes stuck in snow, make
sure that snow is kept clear of the exhaust
pipe and from around the vehicle with the
engine running. Otherwise, deadly carbon
monoxide (CO) gases may enter vehicle in-
terior resulting in unconsciousness and
death.
To assure sufficient fresh air ventilation,
open a window slightly on the side of the ve-
hicle not facing the wind.

327 Operation
Driving instructions

Avoid high engine speeds.

Shift automatic transmission to
position1 (
page 192).

Drive next to the ruts rather than
through them if at all possible.

If the ruts are too deep to drive in, drive
with one side of the vehicle on the
grassy center strip if the route permits.Returning from off-road drivingOff-road driving increases strain on the
vehicle.
We recommend that you inspect the vehi-
cle for possible damage after each off-road
trip. Recognizing any damage and a subse-
quent timely repair reduces the chance of
a possible breakdown or accident later on.
Proceed as follows:

Switch off the off-road driving program
(
page 253).

Switch off the DSR (page 250).

Vehicles with air suspension program*:
Lower the vehicle back to a level
suitable for road conditions, e.g. High-
way/High-speed level (
page 255).

Clean all exterior lamps and check for
possible damage.

Clean the front and rear license plate.
!Check that the ruts are not too deep and
your vehicle’s clearance is sufficient. Otherwise:

your vehicle may be damaged

the underbody of the vehicle may come in
contact with the ground and you may get
stuck
Warning!G
If you feel a sudden significant vibration or
ride disturbance, or you suspect that possi-
ble damage to your vehicle has occurred,
you should turn on the hazard warning flash-
ers, carefully slow down, and drive with cau-
tion to an area which is a safe distance from
the roadway.
Inspect the tires and under the vehicle for
possible damage. If the vehicle or tires ap-
pear unsafe, have it towed to the nearest
Mercedes-Benz Light Truck Center or tire
dealer for repairs.
Damage to the vehicle may influence driving
comfort and pose the risk of accident to you
and other drivers.

328 Operation
Driving instructions

Remove excessive dirt from tires,
wheels, wheel housings, and under-
body.
For instance, after driving in mud, clean
the radiator, chassis, engine, brakes,
and wheels from extreme dirt using a
strong jet of water.

Check tires for possible damage.

Inspect vehicle underbody, oil pan,
brake hoses, etc., as well as vehicle un-
derbody for possible damage.

Check for brush or branches caught in
the underbody.

After continued operation in mud,
sand, water or other dirty conditions
clean the brake discs, wheels, brake
pads and check and clean axle joints.

Conduct a brake test.
Trailer towing Trailer hitch*

Only install a trailer hitch receiver ap-
proved for your vehicle.
For information on availability and in-
stallation, contact an authorized
Mercedes-Benz Light Truck Center.

The bumpers on your vehicle are not
designed for use with clamp-type hitch-
es.
Do not attach rental hitches or other
bumper-type hitches to them.

To reduce the possibility of damage, re-
move the hitch ball adaptor from the
receiver when not in use.
!Brush or branches could increase the possi-
bility of a fire, as well as cut fuel and/or brake
lines, puncture rubber bellows of the axles or
drive shafts.
Warning!G
Failure to use proper equipment and driving
technique can result in a loss of vehicle con-
trol when towing a trailer.
Improper towing or failure to follow the in-
structions in this manual can result in vehi-
cle damage and/or serious personal injury.
Follow the guidelines below carefully to as-
sure safe trailer operation.
Contact an authorized Mercedes-Benz Light
Truck Center should you require an explana-
tion of information contained in this manual.