2002 MERCEDES-BENZ ML320 check engine light

200 Driving instructions
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If the vehicle is parked after being driven on salt treated
roads, the braking efficiency should be tested as soon as
possible after driving is resumed while observing the
safety rules in the previous paragraph.
Winter driving
Have your vehicle winterized at your authorized
Mercedes-Benz Light Truck Center before the onset of
winter.
•Change the engine oil if the engine contains an oil
which is not approved for winter operation. For
viscosity (SAE / CCMC class) and filling quantity,
see page 314.•Check engine coolant anticorrosion / antifreeze
concentration.
•Additive for the windshield washer and headlamp
cleaning system: Add MB Concentrate “S” to a
premixed windshield washer solvent / antifreeze
which is formulated for below freezing temperatures
see page 259.
•Test battery: Battery capacity drops with decreasing
ambient temperature. A well charged battery helps
to ensure that the engine can be started, even at low
ambient temperatures.
•Tires: We recommend M+S rated radial-ply tires on
all four wheels for the winter season. Observe
permissible maximum speed for M+S rated
radial-ply tires and the legal speed limit.
In winter operation, the maximum effectiveness of the
antilock brake system (ABS), the four wheel electronic
traction system (4-ETS+), the electronic stability
program (ESP), and electronic brake proportioning
(EBP) can only be achieved with M+S rated radial-ply
tires and / or snow chains recommended by
Mercedes-Benz. Snow chains maximize performance.
For driving instructions using snow chains see
page 199.
Wa r n i n 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 engine running.
Otherwise, deadly carbon monoxide (CO) gases may
enter vehicle interior resulting in unconsciousness
and death.To assure sufficient fresh air ventilation, open a
window slightly on the side of the vehicle not
facing the wind.

208 Driving instructions
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Returning from off-road driving
Off-road driving increases strain on the vehicle.
We recommend that you inspect the vehicle for possible
damage after each off-road trip. Recognizing any
damage and a subsequent timely repair reduces the
chance of a possible breakdown or accident later on.
Proceed as follows:
•Switch off the LOW RANGE mode, see page 227.
•Remove excessive dirt from tires, wheels, wheel
housings, and underbody. For instance, after driving
in mud, clean the radiator, chassis, engine, brakes,
and wheels from extreme dirt, using a strong jet of
water.
•Inspect frame, oil pan, brake hoses, etc., as well as
vehicle underbody for possible damage.
•Check tires for possible damage, clean all exterior
lamps, and conduct a brake test.•Check for brush or branches caught in the
undercarriage. They could increase the possibility of
a fire, as well as cut fuel and / or brake lines,
puncture rubber bellows of the axles or drive shafts.
•After continued operation in mud, sand, water or
other dirty conditions clean the brake discs, wheels,
brake pads and check and clean axle joints.
Wa r n i n g !
If you feel a sudden significant vibration or ride
disturbance, or you suspect that possible damage to
your vehicle has occurred, you should turn on the
hazard warning flashers, carefully slow down, and
drive with caution 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 appear unsafe, have
it towed to the nearest Mercedes-Benz Light Truck
Center or tire dealer for repairs.

212 Driving instructions
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Towing a trailer
There are many different laws, including speed limit
restrictions, having to do with trailer towing. Make sure
that your rig will be legal, not only for where you reside,
but also for where you will be driving. A good source for
this information can be the police or local authorities.
Before you start driving with the trailer, check the
trailer hitch, break-away switch, safety chains, electrical
connections, lighting and tires. Also adjust the mirrors
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 be sure the brakes are
working properly.
When towing a trailer, check occasionally to be sure that
the load is secure, and that lighting and trailer brakes
(if so equipped) are functioning properly.
Always secure items in the trailer to prevent load shifts
while driving.
Take into consideration that when towing a trailer, the
handling characteristics are different and less stable
from those when operating the vehicle without a trailer.
It is important to avoid sudden maneuvers.The vehicle and trailer combination is heavier, and
therefore is limited in acceleration and climbing ability,
and requires longer stopping distances. It is more prone
to reacting to side wind gusts, and requires more
sensitive steering input.
In order to gain skill and an understanding of the
vehicle’s behavior, you should practice turning,
stopping and backing up in an area which is free from
traffic.
If possible, do not brake abruptly, but rather engage the
brake slightly at first to permit the trailer to activate its
brake. Then increase the braking force.
Caution!
If the trailer should begin to sway, reduce the vehicle’s
speed and use the brake controller by hand to straighten
out the vehicle and trailer. In no case should you
attempt to straighten out the tow vehicle and trailer by
increasing the speed or oversteering and stepping on
the brakes.
If the transmission hunts between gears on inclines,
manually shift to a lower gear (select “4”, “3”, “2”
or “1”). A lower gear and reduction of speed reduces the
chance of engine overloading and / or overheating.

215 Driving systems
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cluster displayPractical hints Car care Index 3Canceling
To cancel the cruise control, briefly push lever to
position 3.
When you step on the brake pedal or the vehicle
speed drops below approximately 20 mph
(30 km / h), for example when driving upgrade, the
cruise control will be canceled.
If the cruise control cancels by itself and remains
inoperative until the engine is restarted, have the
system checked at your authorized Mercedes-Benz
Light Truck Center as soon as possible.
4Resume
If the lever is briefly pushed to position 4 when
driving at a speed exceeding approximately 20 mph
(30 km / h), the vehicle resumes the speed which
was set prior to the cancellation of the cruise
control. The last memorized speed is canceled when
the key in the steering lock is turned to position 1
or 0.Important!
Moving gear selector lever to position “N” switches the
cruise control off.
Wa r n i n g !
Only use the cruise control if the traffic and
weather conditions make it advisable to travel at a
steady speed.• The use of cruise control can be dangerous on
winding roads or in heavy traffic because
conditions do not allow safe driving at a steady
speed.
• The use of cruise control can be dangerous on
slippery roads. Rapid changes in tire adhesion
can result in wheel spin and loss of control.The “Resume” function should only be operated if
the driver is fully aware of the previously set speed
and wishes to resume this particular preset speed.

218 Driving systems
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The BAS / ESP malfunction indicator lamp in the
instrument cluster comes on with the key in steering
lock position 2 and should go out with the engine
running.
If the BAS / ESP malfunction indicator lamp comes on
permanently while the engine is running, a malfunction
has been detected in either system. As a result, it is
possible that now only partial engine output will be
available. If the BAS malfunctions, the brake system
functions in the usual manner, but without BAS.If the charging voltage falls below 10 volts, the
malfunction indicator lamp comes on and the BAS and
the ESP are switched off. When the voltage is above this
value again, the malfunction indicator lamp should go
out and the BAS is operational.
With the ABS malfunctioning, the BAS is also switched
off. Both malfunction indicator lamps come on with the
engine running.
If the BAS / ESP malfunction indicator lamp stays
illuminated, have the BAS or ESP checked at your
authorized Mercedes-Benz Light Truck Center as soon
as possible.

220 Driving systems
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If the charging voltage falls below 10 volts, the
malfunction indicator lamp comes on and the ABS is
switched off. When the voltage is above this value again,
the malfunction indicator lamp should go out and the
ABS is operational.
If the ABS malfunction indicator lamp stays illuminated,
have the system checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.Notes:
To alert following vehicles to slippery road conditions
you discover, operate your hazard warning flashers as
appropriate.
Operating the vehicle on a single axle dynamometer
should only be done for briefly testing the brakes. To do
so, move selector lever to position “N”. The engine must
be shut off (key in steering lock position 0 or 1).
LOW RANGE – ABS
During off-road driving a special low range system for
the antilock brake system (ABS) is operational with
transmission in LOW RANGE mode, see page 229.
When applying the service brakes at speeds below
approximately 18 mph (30 km / h), the front wheels are
locked cyclically to shorten the braking distance (dig in
effect). This affects steering the vehicle.
Wa r n i n g !
ABS cannot prevent the natural laws of physics
from acting on the vehicle, nor can it increase
braking or steering efficiency beyond that afforded
by the condition of the vehicle brakes and tires or
the traction afforded. The ABS cannot prevent
accidents, including those resulting from excessive
speed in turns, following another vehicle too
closely, or aquaplaning. Only a safe, attentive, and
skillful driver can prevent accidents. The
capabilities of an ABS equipped vehicle must never
be exploited in a reckless or dangerous manner
which could jeopardize the user’s safety or the
safety of others.

221 Driving systems
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cluster displayPractical hints Car care Index Four-wheel electronic traction system (4-ETS+)
With the key in steering lock position 2, the yellow
4-ETS+ malfunction indicator lamp{ and the 4-ETS+
warning lampv come on and should go out when
the engine is running.
The 4-ETS+ improves vehicle’s ability to utilize available
traction, especially under slippery road conditions. The
brakes are applied to the spinning wheel and power is
transferred to the wheel(s) with traction.
The traction control engages at vehicle speeds up to
approx. 24 mph (40 km / h), and switches off at
50 mph (80 km / h).
The 4-ETS+ warning lampv, located in the
speedometer dial, starts to flash at any vehicle speed, as
soon as the tires lose traction and the wheels begin to
spin.
Important!
If the 4-ETS+ warning lampv flashes:
•During take-off, apply as little throttle as possible.
•While driving, ease up on the accelerator.
•Adapt your speed and driving to the prevailing road
conditions.4-ETS+ Control
If the yellow 4-ETS+ malfunction indicator lamp{
comes on while the 4-ETS+ warning lampv flashes,
the electronic traction system is being switched off
temporarily to prevent overheating of the drive wheel
brakes.
If the 4-ETS+ malfunction indicator lamp{ comes on
with the engine running, a malfunction has been
detected.
Have the 4-ETS+ checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.
With the ABS malfunctioning, the 4-ETS+ is also
switched off.
Caution!
If the vehicle is towed with the front axle raised (see
towing the vehicle on page 277), or when testing the
parking brake on a brake test dynamometer, the engine
must be shut off (key in steering lock position 0 or 1).
Otherwise, the electronic traction system will
immediately be engaged and will apply the rear wheel
brakes.

222 Driving systems
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Note:
In winter operation, the maximum effectiveness of the
electronic traction system is only achieved with
Mercedes-Benz recommended M+S rated radial-ply tires
and / or snow chains.
LOW RANGE – 4-ETS+
During off-road driving a special low range system for
the four wheel electronic traction system (4-ETS+) is
operational with transmission in LOW RANGE mode,
see page 229.
If one or more tires lose traction while driving downhill
(accelerator released), the 4-ETS+ engages and the
warning lampv, located in the speedometer dial,
starts to flash.Electronic brake proportioning (EBP)
The EBP enhances braking effectiveness by allowing the
rear brakes to supply a greater proportion of the braking
effort without a loss of vehicle stability.
If a warning tone sounds for five seconds and the
symbols É and - are displayed in the instrument
cluster, the system has detected a malfunction and is
switched off. Have the system checked immediately at
an authorized Mercedes-Benz Light Truck Center.
Failure to do so could result in an accident, since the
enhanced braking effect is not available when the
system is switched off.
Note:
When the EBP is switched off, every time the engine is
started, a warning tone will sound for five seconds and
the symbols É and - will light up. In addition,
whenever the brakes are applied at speeds exceeding
25 mph (40 km / h), the warning tone sounds for five
seconds.