2008 MERCEDES-BENZ ML320 check engine

187 Controls in detail
Automatic transmission
Transmission positions
The current transmission position appears
in the multifunction display.
1Current transmission position
!If the current transmission position does not
appear in the multifunction display due to a
malfunction, for example, make sure that the
automatic transmission is in the desired position
by carefully driving off with the transmission in
drive positionD.
ML 63 AMG:
Select program modeC (
page 194).
Do not limit the gear range.
Effect
ìPark position
Shift into park positionP only
when vehicle is stopped. The
park position is not intended to
serve as a brake when the vehi-
cle is parked. Rather, the driver
should always set the parking
brake in addition to shifting into
park positionP to secure the
vehicle.
If the vehicle’s electrical system
is malfunctioning, the automatic
transmission could remain
locked in park positionP.
Have the vehicle checked as
soon as possible by an autho-
rized Mercedes-Benz Light
Truck Center.
!SmartKey:
If you turn off the engine using the SmartKey and

remove the SmartKey from the starter
switch
or

open a front door
the transmission will shift to park positionP
automatically.
Keep in mind that turning off the engine with the
SmartKey alone only will automatically shift the
transmission to neutral positionN.
!KEYLESS-GO*:
If you turn off the engine using the KEYLESS-GO
start/stop button and open a front door, the
transmission will shift to park positionP
automatically.
Keep in mind that turning off the engine using
the KEYLESS-GO start/stop button alone only
will automatically shift the transmission to
neutral positionN.

197 Controls in detail
Automatic transmission
Emergency operation (Limp-Home
Mode)
If vehicle acceleration becomes less re-
sponsive or sluggish or the transmission
no longer shifts, the transmission is most
likely operating in limp-home (emergency
operation) mode. In this mode only second
gear and reverse gear can be activated.
Stop the vehicle in a safe location.
Shift to park positionP.
Turn off the engine.
Wait at least 10 seconds before
restarting.
Restart the engine.
Shift to drive positionD (for second
gear) or reverse gearR.
Have the transmission checked at an
authorized Mercedes-Benz Light Truck
Center as soon as possible.

215 Controls in detail
Climate control
Deactivating
It is possible to deactivate the air condi-
tioning (cooling) function of the climate
control system. The air in the vehicle will
then no longer be cooled or dehumidified.
Press button9 (page 206).
The indicator lamp on the button goes
out.
Activating
Moist air can fog up the windows. You can
dehumidify the air with the air condition-
ing.
Press button9 (page 206) again.
The indicator lamp on the button
comes on.
The air conditioning uses the refrigerant
R134a. This refrigerant is free of CFCs
which are harmful to the ozone layer.
Residual heat and ventilation
With the engine switched off, it is possible
to continue to heat or ventilate the interior
for up to 30 minutes. This feature makes
use of the residual heat produced by the
engine.Activating
Switch off the ignition (page 40).
Press button9 (page 206).
The indicator lamp on the button
comes on.
Deactivating
Press button9 (page 206).
The indicator lamp on the button goes
out.
!If the air conditioning cannot be turned on
again, this indicates that the air conditioning is
losing refrigerant. The compressor has turned
off.
Have the air conditioning checked at the nearest
authorized Mercedes-Benz Light Truck Center.
iHow long the system will provide heating
depends on

the coolant temperature

the battery voltage
Regardless of the temperature and air volume
set on the climate control panel, the interior tem-
perature is set to 72°F (22°C) and the blower
runs on low speed to protect the vehicle battery.
iThe residual heat is automatically turned off:

when the ignition is switched on

after about 30 minutes

if the coolant temperature is too low

if the battery voltage drops

229 Controls in detail
3-zone automatic climate control*
Air conditioning
The cooling function, only operational
when the engine is running, cools the vehi-
cle down to the selected interior tempera-
ture. The cooling function also
dehumidifies the air in the vehicle interior,
thereby preventing the windows from fog-
ging up.Deactivating
It is possible to deactivate the air condi-
tioning (cooling) function of the automatic
climate control system. The air in the vehi-
cle will then no longer be cooled or dehu-
midified.
Press button9 (page 220).
The indicator lamp on the button goes
out. The cooling function switches off
after a short delay.
Activating
Moist air can fog up the windows. You can
dehumidify the air with the air condition-
ing.
Press button9 again.
The indicator lamp on the button
comes on.
The air conditioning uses the refrigerant
R-134a. This refrigerant is free of CFCs
which are harmful to the ozone layer.Using driver-side settings for all tem-
perature zones
You can use the settings of the driver’s
side, such as temperature, air volume and
air distribution, for all temperature zones.
These settings only need to be made once
and the automatic climate control system
will automatically regulate the settings for
all temperature zones quickly and comfort-
ably.
iCondensation may drip out from underneath
the vehicle. This is normal and not an indication
of a malfunction.
Warning!G
If you turn off the cooling function, the
interior air is not dried. The windows can fog
up more quickly. Window fogging may
impair visibility and endanger you and
others.
!If the air conditioning cannot be turned on
again, this indicates that the air conditioning is
losing refrigerant. The compressor has turned
off.
Have the air conditioning checked at the nearest
authorized Mercedes-Benz Light Truck Center.

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.

322 Operation
Driving instructions
Checklist before off-road driving
Engine oil level

Check the engine oil level with the oil
dipstick (
page 343).
Only with a proper oil level can the
vehicle obtain a trouble-free oil supply,
even on steep gradients.Tires

Check the tread depth and maintain
specified tire inflation pressure
(a placard with the recommended tire
inflation pressures is located on the
driver’s door B-pillar (
page 352)).

Check tires for possible damage and
remove foreign objects.

Replace missing valve caps.
Rims

Dented or bent rims can cause tire in-
flation pressure loss and damage the
tire beads. For this reason, check and,
if necessary, change rims before driv-
ing off-road.
Vehicle tool kit

Check if the vehicle jack (page 450)
is functional.

In all cases take the vehicle tool kit, a
strong tow rope, a shovel and a small
plank (to put under the vehicle jack on
sandy soil) with you.Driving in steep terrain
Slope angle
1 Overhang angle, front
2Overhang angle, rear
!If the engine oil level warning lamp
(
page 434) comes on while driving, stop the
vehicle in a safe location or as soon at is safe to
do so. Check the engine oil level (
page 343).
The engine oil level warnings should not be
ignored. Extended driving with the symbol
displayed could result in serious engine damage
that is not covered by the Mercedes-Benz
Limited Warranty.
Vehicles with
steel suspen-
sion111
1Vehicles with AMG Sport-Package*
2
31°22°29°

323 Operation
Driving instructions

Comply with the warnings
(
page 319) and rules for off-road
driving (
page 321).

Driving on embankments, slopes and
other steep inclines should only be
done straight up or downhill, i.e. in the
line of gravity. Maximum vehicle climb-
ing ability is a 100% grade which is
equivalent to a slope angle of
45 degrees. Keep in mind that the
climbing ability of the vehicle depends
on terrain conditions.

Shift automatic transmission to
position1 (
page 192).

Drive slowly.

Avoid excessive engine speeds – drive
with moderate engine speeds
(max. 3 000 rpm).

Utilize the engine’s braking power
when descending a slope, observe the
engine speed (do not overrev the en-
gine). Apply the service brake as need-
ed.

Check the brakes after a lengthy down-
grade drive.Traction in steep terrain
The maximum vehicle climbing ability is a
100% grade which is equivalent to a slope
angle of 45 degrees. Keep in mind that the
climbing ability of the vehicle depends on
terrain conditions.
Be easy on the accelerator and watch for
continuous wheel traction when driving in
steep terrain.
Vehicles with air
suspension pro-
gram*111
1Vehicles with AMG Sport-Package*
2
Raised level34°29°31°
Highway29°22°27°
ML 63 AMG12
Raised level28°29°
Highway23°24°
iFor maximum engine speed, see “Instru-
ment cluster” (
page 26) and see “Engine”
(
page 513).
Warning!G
Never turn the vehicle around on steep
inclines. The vehicle might roll over. If the
vehicle cannot complete the attempted
climb, back it down in reverse gear.
iThe hill start assist system supports you
when driving uphill.
For more information, see “Hill start assist sys-
tem” (
page 191).
iThe 4-ETS helps greatly when starting out on
a steep incline when the front wheels have then
the tendency to slip due to the weight shifting
towards the rear axle.
The 4-ETS recognizes the situation and limits the
torque for the front wheels by braking them.
Simultaneously the torque for the rear wheels is
increased.

324 Operation
Driving instructions
Driving across a hilltop
Decelerate just ahead of a hilltop (do not
shift automatic transmission to
positionN), to prevent the vehicle from
speeding up too much after climbing a hill.
Use the momentum of the vehicle to drive
across the hilltop.
After climbing a hill, driving in this manner
prevents the vehicle from:

losing ground contact when cresting
hills

losing its forward momentum

speeding up too much after climbing
the hill
Driving downhill

Drive slowly.

Do not drive at an angle to the incline.
Steer into the line of gravity and drive
with the front wheels pointing straight
downhill. Otherwise, the vehicle may
slide sideways off the path and roll
over.

Shift automatic transmission to
position1 (
page 192).

On steep inclines, use the Downhill
Speed Regulation (
page 249).

Utilize the engine’s braking power to
reduce vehicle speed.
If this is insufficient, apply the brakes
gently. Make sure the vehicle is moving
in the line of gravity.

Check the brakes after a lengthy down-
grade drive.Driving through water
1Fording depth
iThe special Off-road – ABS (page 99) set-
ting allows for precise and brief (cyclical) block-
ing of the front wheels, permitting them to dig
into loose ground.
Remember that, when stopped, the front wheels
slide across a surface and thus lose their ability
to steer the vehicle.Vehicles with steel
suspension1
20.00 in (50 cm)
Vehicles with air
suspension
program* or
ML 63 AMG1
Raised level20.00 in (50 cm)