2008 MERCEDES-BENZ GL320 parking

349 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 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.
Refer to the description of the Brake Assist
System (BAS) (
page 103).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 437).
Observe additional messages in the multi-
function display that may appear
(
page 469).
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.
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350 Operation
Driving instructions
Parking brake
When driving on wet roads or dirt covered
surfaces, road salt and/or dirt can get into
the parking brake. To prevent corrosion
and a reduction in the braking power of the
parking brake, observe the following:
From time to time, lightly engage the
parking brake before driving off.
Drive a distance of approximately
110 yds (100 m) at a maximum speed
of 12 mph (20 km/h).
Driving off
Apply the brakes to test them briefly after
driving off. Perform this procedure only
when the road is clear of other traffic.
Warm up the engine smoothly. Do not
place full load on the engine until the oper-
ating temperature has been reached.Parking
Warning!G
While performing this procedure, please
assure that the vehicle is stopped before
applying the parking brake. Otherwise the
rear wheels could lock up. You could lose
control of the vehicle and cause an accident.
In addition, the vehicle’s brake lights do not
light up when the parking brake is engaged.
Make sure not to endanger any other road
users when you engage the parking brake.
!When driving off on a slippery surface, do
not allow a drive wheel to spin for an extended
period with the ESP
® switched off. Doing so may
cause serious damage to the drivetrain which is
not covered by the Mercedes-Benz Limited
Warranty.
!Simultaneously depressing the accelerator
pedal and applying the brake reduces engine
performance and causes premature brake and
drivetrain wear.
Warning!G
Do not park this vehicle in areas where com-
bustible materials such as grass, hay or
leaves can come into contact with the hot
exhaust system, as these materials could be
ignited and cause a vehicle fire.
To reduce the risk of personal injury or
damage to the vehicle drivetrain as a result
of vehicle movement, before turning off the
engine and leaving the vehicle always:

Keep right foot on brake pedal.

Firmly depress parking brake pedal.

Set the automatic transmission to
positionP.

Slowly release brake pedal.

When parked on an incline, turn front
wheel towards the road curb.
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367 Operation
Driving instructions
Make sure the automatic transmission
is set toP (
page 191).
Set the parking brake for the vehicle
(
page 67).
Start the engine (page 56).
Set the vehicle level to Highway
(
page 279).
Vehicle with ADS*: Set the ADS* to
AUTO or COMFORT (
page 278).
Turn off the engine (page 68).
Close all doors and the tailgate.
Attach the trailer.
Plug in all electrical connectors.
Towing a trailer
There are many different laws, including
speed limit restrictions, having to do with
trailer towing. Make sure your rig will be le-
gal, not only for where you reside, but also
for where you will be driving. A good
source for this information can be the po-
lice or local authorities.Note the following points, when driving
with the trailer:
In order to gain skill and an understand-
ing of the vehicle’s behavior, you
should practice turning, stopping and
backing up in an area which is free from
traffic.

Before you start driving check the

trailer hitch

break-away switch

safety chains

electrical connections

lighting and tires

Adjust the mirrors (page 51) to
permit unobstructed view beyond rear
of trailer.

If the trailer has electric brakes, start
your vehicle and trailer moving slowly,
and then apply only the trailer brake
controller by hand to make sure the
brakes are working properly.
!Do not connect a trailer brake system (if
trailer is so equipped) directly to the vehicle’s
hydraulic brake system, as your vehicle is
equipped with antilock brakes. If you do, neither
the vehicle’s brakes nor the trailer’s brakes will
function properly.
iThe provided vehicle electrical connector for
trailer towing has a brake signal wire for hook-up
to a brake controller.
You should consider using a trailer sway control
system. For further information, contact an
authorized Mercedes-Benz Light Truck Center.
iWhen you are towing a trailer, the vehicle
level always remains in the Highway setting.
The following applies additionally when towing a
trailer:

The vehicle is lowered to the highway level
when it reaches a speed of 5 mph (8 km/h)
if not set to highway level.

The high-speed level is not available.
The restrictions that apply to towing also apply
when using accessories that are connected to
the trailer power socket, such as a bicycle rack.
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369 Operation
Driving instructions
Uncoupling the trailerMake sure the automatic transmission
is set toP (
page 191).
Set the parking brake for the vehicle
(
page 67).
Start the engine (page 56).
Close all doors and the tailgate.
Set the parking brake for the trailer.
Disconnect all electrical plug connec-
tors.
Uncouple the trailer.
Make sure that the trailer coupling is
free of load.
Turn off the engine (page 68).
Warning!G
While you are coupling or decoupling a trail-
er, make sure that you do not

lock or unlock

open or close
a vehicle door or the tailgate.
The vehicle’s level could change and you
could endanger yourself and/or others as a
result.
Make sure that you do not operate the ADS
button* (
page 279) or the vehicle level
control system (
page 279) when cou-
pling/decoupling the trailer.
Warning!G
As soon as you disconnect the electrical
connection between the trailer and the
vehicle, the vehicle will lower. To help avoid
personal injury, make sure no one is near
the wheel housing or underneath the vehicle
before the electrical connection is discon-
nected.
When you uncouple the trailer, the vehicle is
temporarily raised because the springs are
relieved of load. Be especially careful during
this process, as you could otherwise injure
yourself and/or others. Make sure that any
persons remaining in the vehicle do not
press the switches for vehicle level control
or the ADS*.
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428 Operation
Vehicle care
Automatic car wash
You can have your car washed in an auto-
matic car wash from the start. Automatic
car washes without brushes are prefera-
ble.
To protect the filter system, switch the
climate control system (
page 216) or
the automatic climate control system*
(
page 230) to air recirculation mode.
If the vehicle is very dirty, prewash it
before running it through the automatic
car wash.When taking the vehicle through an auto-
matic conveyor type car wash, observe the
following instructions.Vehicles with SmartKey:
With the vehicle at a standstill and the
ignition switched on shift the automatic
transmission to neutral positionN.
If engaged, release the parking brake
(
page 59).
Switch off the ignition and leave the
SmartKey in the starter switch.
Vehicles with KEYLESS-GO*:
With the vehicle at a standstill, depress
the brake pedal and keep it pressed.
With the ignition switched on shift the
automatic transmission to park
positionP.
Release the brake pedal.
Remove the KEYLESS-GO* start/stop
button from the starter switch
(
page 43).
Insert the SmartKey with
KEYLESS-GO* into the starter switch.
Switch on the ignition.
!Do not clean your vehicle in an automatic
touchless car wash which use caustic spray.
Otherwise the caustic spray will damage the
paint or ornamental moldings.
!Make sure that the windshield wiper switch
is set to0 (
page 63). Otherwise, e.g. the rain
sensor could activate and cause the wipers to
move unintentionally. This may lead to vehicle
damage.
Due to the width of the vehicle, fold in exterior
rear view mirrors prior to running the vehicle
through an automatic car wash to prevent
damage to the mirrors.
Warning!G
When leaving the SmartKey or SmartKey
with KEYLESS-GO* in the starter switch, do
not leave children unattended in the vehicle.
It is possible for children to switch on the
ignition which could result in unsupervised
use of vehicle equipment.
A child’s unsupervised access to a vehicle
could result in an accident and/or serious
personal injury.
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429 Operation
Vehicle care
Depress the brake pedal.
Shift the automatic transmission to
neutral positionN.
Release the brake pedal.
If engaged, release the parking brake
(
page 59).
Switch off the ignition and leave the
SmartKey with KEYLESS-GO* in the
starter switch.Ornamental moldings
For regular cleaning and care of ornamen-
tal moldings, use a damp cloth.Headlamps, brake lamps, tail lamps,
side markers, turn signal lenses
Use a mild car wash detergent, such as
Mercedes-Benz approved Car Sham-
poo, with plenty of water.
iAfter running the vehicle through an auto-
matic car wash, wipe any wax off of the wind-
shield (
page 431). This will prevent smears
and reduce wiping noise which can be caused by
residual wax on the windshield.
When leaving the car wash, make sure that the
mirrors are folded out. Otherwise they may
vibrate.
!Do not use chrome cleaner on ornamental
moldings. Although ornamental moldings may
have chrome appearance, they could be made of
anodized aluminum that will be damaged when
cleaned with chrome cleaner. Instead, use a
damp cloth to clean those ornamental moldings.
For very dirty ornamental moldings of which you
are sure are chrome-plated, use a chrome clean-
er. If in doubt whether an ornamental molding is
chrome-plated, contact an authorized
Mercedes-Benz Light Truck Center.
!Only use window cleaning solutions that are
suitable for plastic lamp lenses. Window clean-
ing solutions which are not suitable may damage
the plastic lamp lenses of the headlamps. There-
fore, do not use abrasives, solvents or cleaners
that contain solvents.
Never apply strong force and only use a soft,
non-scratching cloth when cleaning the lenses.
Do not attempt to wipe dirty lenses with a dry
cloth or sponge.
Otherwise you may scratch or damage the lens
surface.
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437 Practical hints
What to do if …
ProblemPossible cause/conse-
quenceSuggested solution
-The yellow ABS indicator lamp comes on while
the engine is running.The self-diagnosis has not yet
been completed yet.The display will clear after driving a short
distance at a vehicle speed of above
12 mph (20 km/h).
;(USA only)
3(Canada only)
The red brake warning lamp
comes on while driving and an
acoustic warning sounds.You are driving with the
parking brake set.Release the parking brake
(
page 59).
There is insufficient brake fluid
in the reservoir.Risk of accident! Carefully stop the
vehicle in a safe location or as soon as
it is safe to do so.
Apply the parking brake (page 67).
Contact an authorized
Mercedes-Benz Light Truck Center.
Do not add brake fluid! This will not
solve the problem.
Warning!G
Driving with the brake warning lamp illumi-
nated can result in an accident. Have your
brake system checked immediately if the
brake warning lamp stays on.
Do not add brake fluid before checking the
brake system. Overfilling the brake fluid res-
ervoir can result in spilling brake fluid on hot
engine parts and the brake fluid catching
fire. You can be seriously burned.!If you find that the brake fluid in the brake
fluid reservoir has fallen to the minimum mark or
below, have the brake system checked for brake
pad thickness and leaks.
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439 Practical hints
What to do if …
ProblemPossible cause/consequenceSuggested solution
?(USA only)
±(Canada only)
The yellow engine malfunc-
tion indicator lamp comes
on while driving.There is a malfunction in:

The fuel management
system

The ignition system

The emission control system

Systems which affect
emissions
Such malfunctions may result in
excessive emissions values and
may switch the engine to its
limp-home (emergency opera-
tion) mode.
Have the vehicle checked as soon as
possible by an authorized
Mercedes-Benz Light Truck Center.
An on-board diagnostic connector is
used by the service station to link the
vehicle to the shop diagnostics system.
It allows the accurate identification of
system malfunctions through the read-
out of diagnostic trouble codes. It is lo-
cated in the front left area of the
footwell next to the parking brake pedal.
iSome states may by law require you to visit
a workshop as soon as the engine malfunction
indicator lamp comes on. Check local require-
ments.
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