engine MERCEDES-BENZ ML320 1997 Complete Repair Manual

172
Automatic transmission
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Emergency operation (Limp home mode)
If vehicle acceleration worsens or the transmission no
longer shifts, the transmission is most likely operating
in Limp home mode which engages when there is a
malfunction of the transmission. This condition may be
accompanied by the “CHECK ENGINE” malfunction
indicator lamp in the instrument cluster coming on.
In this mode only the 2nd gear or reverse gear can be
activated. To engage 2nd gear or reverse:
1. Sto p t h e v e h i c l e .
2. Move selector lever to position “P”.
3. Turn off the engine.
4. Wait approximately 10 seconds.
5. Restart the engine.
6. Move selector lever to position “D” (for 2nd gear), or move selector lever to position “R” (for reverse gear).
Have the transmission checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.

174
Driving instructions
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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 roof rack when not in use,
• allow engine to warm up under low load use,
• avoid frequent acceleration and deceleration,
• have all maintenance work performed at regular
intervals by 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
country. Drinking and driving
Pedals
Wa r n i n g !
Drinking or taking drugs and driving can be a very
dangerous combination. Even a small amount of
alcohol or drugs can affect your reflexes,
perceptions and judgement.The possibility of a serious or even fatal accident is
sharply increased when you drink or take drugs
and drive.Please don’t drink or take drugs and drive or allow
anyone to drive after drinking or taking drugs.Wa r n i n g !
Keep driver’s foot area clear at all times. Objects
stored in this area may impair pedal movement.

175
Driving instructions
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Power assistance
Brakes The condition of the parking brake system is checked
each time the vehicle is in the shop for the required
maintenance service.
If the parking brake is released and the brake warning
lamp in the instrument cluster stays on and there is no
audible warning (EBP), the brake fluid level in the
reservoir is too low.
Brake pad wear or a leak in the system may be the
reason for low brake f luid in the reservoir.
Have the brake system inspected at an authorized
Mercedes-Benz Light Truck Center immediately.
All checks and service work on the brake system should
be carried out by an authorized Mercedes-Benz Light
Truck Center.
Install only brake pads and brake fluid recommended by
Mercedes-Benz.
Wa r n i n g !
When the engine is not running, the brake and
steering systems are without power assistance.
Under these circumstances, a much greater effort is
necessary to stop or steer the vehicle.Wa r n i n g !
After driving in heavy rain for some time without
applying the brakes or through water 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. Be sure to 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 effectiveness. It may
not be possible to stop the vehicle in sufficient time
to avoid an accident.
Wa r n i n 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.

176
Driving instructions
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Caution!
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.
After hard braking, it is advisable to drive on for some
time, rather than immediately parking, so the air stream
will cool down the brakes faster.
Driving off
Apply the service 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 operating temperature has been
reached.
When starting off on a slippery surface, do not allow one
drive wheel to spin for an extended period with the ESP
switched off. Doing so may cause serious damage to the
drive train which is not covered by the Mercedes-Benz
Limited Warranty. Parking
Important!
It is advisable to set the parking brake whenever
parking or leaving the vehicle. In addition, move
selector lever to position “P”.
When parking on hills, always set the parking brake.
Wa r n i n g !
To reduce the risk of personal injury as a result of
vehicle movement, before
turning off the engine
and leaving the vehicle, always:
1. Keep right foot on the service brake pedal.
2. Firmly depress parking brake pedal.
3. Move the selector lever to position “P”.
4. Slowly release the service brake pedal.
5. Turn front wheels towards the road curb.
6. Turn the key to steering lock position 0 and remove.
7. Take the key and lock vehicle when leaving.

180
Driving instructions
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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, move
selector lever to position “N”. Try to keep the vehicle
under control by corrective steering action.
Caution!
Do not use LOW RANGE mode when driving on ice or
packed snow. At speeds below 18 mph (30 km / h)
vehicle steering is adversely affected by the LOW
RANGE ABS.
Road salts and chemicals can adversely affect braking
efficiency. Increased pedal force may become necessary
to produce the normal brake effect. We therefore
recommend depressing the brake pedal periodically
when traveling at length on salt-strewn roads. This can
bring road salt impaired braking efficiency back to
normal. A prerequisite is, however, that this be done
without endangering other drivers on the road. 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.
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.

181
Driving instructions
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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 292.
• 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 237.
• 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 179.
Deep water
Caution!
Do not drive through flooded areas or water of unknown
depth. Before driving through water, determine its
depth. It should not be deeper than approximately
20 inches (50 cm).
If you must drive through deep water, drive slowly to
prevent water from entering the engine compartment or
passenger compartment, being ingested by the air
intake, possibly causing damage to electrical
components or wiring, to engine or transmission that is
not covered by the Mercedes-Benz Limited Warranty.

182
Driving instructions
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Passenger compartment
Block heater (Canada only)
The engine is equipped with a block heater.
The electrical cable may be installed at your authorized
Mercedes-Benz Light Truck Center. Traveling abroad
Abroad, there is a widely-spread Mercedes-Benz service
network at your disposal. If you plan to travel into areas
which are not listed in the index of your Mercedes-Benz
Light Truck Center directory, you should request
pertinent information from your authorized
Mercedes-Benz Light Truck Center.
Wa r n i n g !
Always fasten items being carried as securely as
possible.In an accident, during hard braking or sudden
maneuvers, loose items will be thrown around
inside the vehicle, and cause injury to vehicle
occupants unless the items are securely fastened in
the vehicle.The trunk is the preferred place to carry objects.

185
Driving instructions
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Driving on embankments, slopes and other steep
inclines should only be done straight up or downhill, i.e.
in the line of gravity.
Do not drive along the side of a slope (danger of vehicle
rollover). If in doing so, the vehicle begins to show a
tendency to roll, immediately steer into a line of gravity
(straight up or downhill).
To help avoid the vehicle rolling over, never turn it
around on steep inclines. If the vehicle cannot complete
the attempted climb, back it down in reverse gear.
Utilize the engine’s braking power when descending a
slope, observe the engine speed (do not overrev the
engine). Apply the service brake as needed.
Check the brakes after a lengthy downgrade drive.
Notes:
Avoid excessive engine speeds – drive with moderate
engine speeds (max. 3000 RPM).
Select gear range “2” or “1” on the automatic
transmission, see page 165. Traction in steep terrain:
Be easy on the accelerator and watch for continuous
wheel traction when driving in steep terrain.
The 4-ETS+ helps greatly when starting out on a steep
incline. The front wheels have then the tendency to slip
due to the weight reduction over the front axle. The ETS
recognizes the situation and limits the torque for the
front wheels by braking them. Simultaneously the
torque for the rear wheels is increased.
See page 203 for four wheel electronic traction system
(4-ETS+).
Driving across a hilltop:
To prevent the vehicle from speeding up too much after
climbing a hill, decelerate just ahead of a hilltop (do not
select gear range “N”). Use the momentum of the
vehicle to drive across the hilltop. Driving in this
manner prevents the vehicle from jumping across the
hilltop and thus loosing its forward momentum.

186
Driving instructions
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Driving downhill:
Select gear range “1” on the automatic transmission,
see page 165.
Drive downhill observing the same rules as driving
uphill.
Driving on embankments, slopes and other steep
inclines should only be done straight up or downhill, i.e.
in the line of gravity.
Do not drive along the side of a slope (danger of vehicle
rollover). If in doing so, the vehicle begins to show a
tendency to roll, immediately steer into a line of gravity
(straight up or downhill). Utilize the engine’s braking power when descending a
slope, observe the engine speed (do not overrev the
engine). Apply the service brake as needed.
The special low range ABS setting allows for precise and
brief (cyclical) blocking of the front wheels, permitting
them to dig into loose ground. Remember that the front
wheels when stopped, slide across a surface, thus loose
their ability to steer the vehicle.
Check the brakes after a lengthy downgrade drive.
Important!
Only apply the service brake if the vehicle travels
straight downhill, i.e. in the line of gravity.

187
Driving instructions
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Driving through water
1 20 in (50 cm)
Before driving through water, determine its depth. It
should not be deeper than approximately
20 inches (50 cm). Switch to LOW RANGE mode before driving through
water.
Switch off the exterior lamps as well as the climate
control.
Enter the water only at a shallow spot. Never take a
running start. Drive slowly, avoiding a bow wave.
Do not stop vehicle immersed in water, and do not shut
off the engine.
To dry the brakes, apply pressure to the brake pedal
several times after leaving the water.