Downhill Drive Support
Operating principle
The Downhill Drive Support maintains a constant speed on a steep downhill sec-
tion when driving forwards and backwards by automatically intervening in the
brake system of all wheels. It prevents the wheels locking because the ABS re-
mains active. The warning light in the instrument cluster indicates that the
Downhill Drive Support is available ⇒ page 30.
The vehicle speed, which is maintained by the Assist System, is selected by the
driver while driving on a downhill section as of the moment the first intervention
of the Assist System is performed or else, while driving on a downhill section, the
driver must control the vehicle speed until the Assist System intervenes for the
first time. When the Assist System actively intervenes, this is indicated by the
warning light flashing or by a pulsating movement of the brake pedal, similar to
the intervention of the ABS.
You can increase or reduce the speed, even when no gear is engaged, by operat-
ing the accelerator or brake pedal. Thus the function is always interrupted and is
reactivated afterwards.
The Downhill Drive Support is activated automatically if the following conditions
are met:
● the Off-road mode is switched on and the warning light lights up in the in-
strument cluster,
● the engine of the vehicle is running and either the 1st, 2nd, 3rd gear, the re-
verse gear or no gear is engaged,
● the engine of the vehicle is running, the selector lever of the automatic gear-
box is in the position R, N, D, S or Tiptronic,
● the speed is less than 30 km/h,
● the downhill gradient is at least 10 % (when driving over sleepers the limit can
briefly drop to 8 %),
● neither the accelerator nor the brake pedal is operated.
It is however a requirement that the vehicle has sufficient grip on the soil. The
Downhill Drive Support cannot properly fulfil its function on slushy soil due to
physical reasons (ice or mud).
The Downhill Drive Support is deactivated when braking or accelerating or if the
downhill gradient is less than 8 %. Manual gearbox
The vehicle speed is steadily regulated by the Assist System depending on the
type of gearbox or engine:
● 1. gear - approx. 8 1)
- 30 km/h
● 2. gear - approx. 13 1 )
- 30 km/h
● 3. gear - approx. 22 1 )
- 30 km/h
● Reverse gear - approx. 9 1 )
- 30 km/h
● Neutral for driving forwards - as well as driving backwards - approx. 2 1 )
- 30
km/h
Automatic gearbox
● Selector lever in the position D, S or Tiptronic (for the 1st, 2nd, 3rd gear) for
driving forwards - approx. 2 - 30
km/h
● Selector lever in the position R for driving backwards - approx. 2 - 30 km/h
● Selector lever in the position N for driving forwards as well as backwards - ap-
prox. 2 - 30
km/h Note
● During an intervention of the Downhill Drive Support, the brake lights do not
light up.
● Do not switch off the Off-road mode during an intervention of the Assist Sys-
tem. 1)
The indicated values represent the average of the lower speed limits if a gear is engaged (depending
on the type of gearbox or engine). 161
Intelligent technology Using the system Safety Driving Tips General Maintenance Breakdown assistance Technical data
Driving and the environment
The first 1 500 kilometres and then afterwards
New engine The engine has to be run in during the first 1 500 kilometres.
Up to 1 000 kilometres
– Do not drive faster than 3/4 of the maximum speed of the gear in use, that is
3/4 of the maximum permissible engine speed.
– Do not use full throttle.
– Avoid high engine revolutions.
– Do not tow a trailer.
From 1 000 up to 1 500 kilometres
– Increase the power output of the engine gradually up to the full speed of the
gear engaged, that is up to the maximum permissible engine revolutions.
During the first operating hours the engine has higher internal friction than later
until all of the moving parts have harmonized. The driving style which you adopt
during the first approx.1 500 kilometres plays a decisive part in the success of run-
ning in your car.
You should not drive at unnecessarily high engine revolutions even after the run-
ning-in period is complete. The maximum permissible engine speed is marked by
the beginning of the red zone on the scale of the revolutions counter. Shift up in-
to the next higher gear on a vehicle fitted with manual gearbox before the red
zone is reached. During acceleration (depressing the accelerator) exceptionally
high engine speeds are automatically reduced, yet the engine is not protected
against too high engine speeds which are caused by incorrectly shifting down the
gears resulting in a sudden increase of the engine speeds above the permitted
maximum revolutions which can lead to engine damage.
For a vehicle fitted with a manual gearbox the converse situation also applies: Do
not drive at engine revolutions which are too low. Shift down as soon as the en-
gine is no longer running smoothly. CAUTION
All the speed and engine revolution figures apply only when the engine is at its
normal operating temperature. Never rev up an engine which is cold, neither when
the vehicle is stationary nor when driving in individual gears. For the sake of the environment
Not driving at unnecessarily high engine revolutions and shifting to a higher gear
as early as possible are ways to minimise fuel consumption and operating noise
levels and protects the environment.
New tyres New tyres have to be “run in” since they do not offer optimal grip at first. You
should take account of this fact for the first 500 kilometres and drive particularly
carefully.
New brake pads Allow for the fact that new brake pads do not achieve their full braking efficiency
until approximately 200 kilometres. New brake pads must be first “run in” before
they develop their optimal friction force. You can, however, compensate for this
slightly reduced braking force by increasing the pressure on the brake pedal.
This guideline also applies to any new brake pads installed at a future date.
During the running-in period, you should avoid excessive stresses on the brakes.
This includes, for example, violent braking, particularly from very high speeds, and
also when crossing mountain passes.
Catalytic converter Proper operation of the emission control system (catalytic convert-
er) is of major significance for driving your vehicle in an environ-
mentally conscious way.
Please refer to the following guidelines: £162
Driving and the environment
–
For vehicles with petrol engine only refuel with unleaded petrol ⇒ page 186,
Fuel.
– Never run the fuel tank completely empty.
– Do not switch off the ignition while you are driving the vehicle.
– Do not pour too much oil into the engine ⇒
page 192, Replenishing engine oil.
If you drive your vehicle in a country in which unleaded petrol is not available, you
must have the catalytic converter replaced later when driving the vehicle into a
country in which use of a catalytic converter is mandatory. WARNING
● In view of the high temperatures which may be produced in the catalytic
converter, one should always park a vehicle in such a way that the catalytic
converter cannot come into contact with easily flammable materials below the
vehicle - a risk of fire!
● Never use additional underbody protection or corrosion-protection agents
for the exhaust pipes, catalytic converters or heat shields. Such substances
might ignite when driving - risk of fire! CAUTION
● On vehicles fitted with a catalytic converter, never let the fuel tank run com-
pletely empty. An irregular fuel supply can result in poor ignition or misfiring. Un-
burnt fuel may get into the exhaust system and damage the catalytic converter.
● Filling the tank even only once with leaded petrol will result in the catalytic
converter being destroyed.
● If you detect misfiring, a drop in performance or irregular engine running when
driving, reduce your speed immediately and have the vehicle inspected by the
nearest specialist garage. The symptoms described may be caused by a fault in
the ignition system. Unburnt fuel may get into the exhaust system and damage
the catalytic converter. For the sake of the environment
Even if the exhaust system is operating properly, a sulphur-like exhaust odour
may be produced under certain operating conditions of the engine. This depends
on the sulphur content of the fuel. It is often sufficient to refuel with unleaded
premium-grade petrol of a different brand or at a different filling station. Driving in an economical and environmentally
conscious manner
General Your personal style of driving is a major factor.
Your fuel consumption, any pollution of the environmental and the wear-and-tear
to the engine, brakes and tyres, depend essentially on three factors:
● your personal style of driving,
● the conditions under which your vehicle is operated,
● technical aspects.
You can easily improve your fuel economy by 10 - 15 percent by driving in an eco-
nomical way with foresight. This section is intended to provide you with a number
of tips on how to protect the environment and at the same time save money.
The fuel consumption can naturally also be influenced by factors which are be-
yond the driver's control. It is, for example, normal for the fuel consumption to in-
crease in winter and under worsened conditions such as poor road conditions,
towing a trailer, etc.
The technical requirements for low fuel usage and economic efficiency of the ve-
hicle have already been built into the vehicle at the works. Special attention has
been given to minimising negative effects on the environment. It is necessary to
take note of the guidelines given in this chapter in order to make best use of
these characteristics and to maintain their effectiveness.
The optimal engine speed should be obtained when accelerating, in order to avoid
a high fuel consumption and resonance of the vehicle.
Looking ahead when driving A vehicle's highest fuel consumption occurs it accelerates.
Avoid accelerating and braking unnecessarily. If you drive with foresight you will
not need to brake so often and will also then not have to accelerate so much. Let
your vehicle coast to a stop, for example, if this is possible, when you see that the
next set of traffic lights is at red. 163
Driving and the environment Using the system Safety Driving Tips General Maintenance Breakdown assistance Technical data
WARNING
● Driving through water, mud, sludge etc. can reduce the braking power and
extend the braking distance - risk of accident!
● Avoid sudden and severe braking manoeuvres immediately after driving
through bodies of water.
● After driving through bodies of water, the brakes must be cleaned and
dried as soon as possible by intermittent braking. Only apply the brakes for
the purpose of drying and cleaning the brake discs if the traffic conditions per-
mit this. Do not place any other road users in jeopardy. CAUTION
● When driving through bodies of water, parts of the vehicle such as the engine,
gearbox, catalytic converter, chassis or electrics can be severely damaged.
● Oncoming vehicles can generate water waves which can exceed the permissi-
ble water level for your vehicle.
● Potholes, mud or rocks can be hidden under the water making it difficult or im-
possible to drive through the body of water.
● Do not drive through salt water. The salt can lead to corrosion. Immediately
rinse all the parts of the vehicle, which came into contact with the salt water, with
fresh water. Note
After driving through a body of water, we recommend that the vehicle is checked
by a specialist garage.
Off-road driving Important information WARNING
● Never drive too fast, particularly not around curves, and never undertake
extreme driving manoeuvres.
● Always adjust your speed and adapt your style of driving to suit road, off-
road, traffic and weather conditions. WARNING (Continued)
● In case the vehicle is stationary on a hillside at a steep angle, do not exit
the vehicle when it is facing downhill. Through this the overall centre of gravi-
ty can shift in such a way that the vehicle tilts and rolls down the hillside -
hazard! Always carefully exit your vehicle on the side facing uphill
⇒ page 174
.
● A lack of experience and knowledge when driving off-road can lead to criti-
cal situations and serious injuries.
● Never choose a dangerous route and never take a risk which could jeop-
ardize your safety and that of your passengers. If you cannot go on or if you
doubt the safety of the route, turn back and choose another way. Even a ter-
rain, which looks harmless, can be difficult and dangerous, and may bring you
and your passengers into a critical situation.
● If you have not fastened your seat belt correctly or you are not wearing
your seat belt at all, or you are holding the steering wheel incorrectly when
driving off-road, the risk of severe or even fatal injuries increases. Correctly
fastened seat belts reduce serious injuries in case of sudden braking manoeu-
vers and accidents. As long as the vehicle is in motion, always have your seat
belt and those of your passengers correctly fastened. Take your thumbs off
the steering wheel when driving off-road. Should resistance build up in front
of the wheels, the steering wheel may suddenly and unexpectedly spin and
hurt you. Hold the steering wheel with both hands firmly on the outer edge in
the 9 o'clock and 3 o'clock position.
● If you have not fastened your seat belt correctly or you are not wearing
your seat belt at all, or you are holding the steering wheel incorrectly when
driving off-road, the risk of severe or even fatal injuries increases.
● Correctly fastened seat belts reduce serious injuries in case of sudden
braking manoeuvres and accidents. Therefore you and your passengers must
always fasten your seat belts correctly as long as the vehicle is moving.
● Take your thumbs off the steering wheel when driving off-road. If the
wheels hit an obstacle, the steering wheel may suddenly and unexpectedly
spin and hurt you!
● Never use the cruise control system when driving off-road. The use of the
cruise control system when driving off-road is unsuitable and can even be
dangerous.
● Do not drive over embankments, ramps or hillsides at too high a speed.
This can lead to the wheels of the vehicle lifting off the ground so that you
can no longer steer and control the vehicle. £168
Driving and the environment
CAUTION
● Pay attention to the ground clearance of the vehicle! The vehicle can be se-
verely damaged and become disabled once it touches the ground.
● Never drive off-road with an almost empty fuel tank. The fuel supply to the en-
gine can be interrupted and therefore the catalytic converter can be severely
damaged.
● Do not leave your foot on the clutch pedal or let the clutch slip when driving
off-road. Overwise you may unintentionally depress the clutch pedal on uneven
ground leading to a loss of control over the vehicle. In addition, the force for con-
necting the engine and the gearbox is lost. Moreover, driving while letting the
clutch slip causes a fast wear of the clutch linings. Note
The fuel consumption is higher when driving off-road than when driving on con-
ventional roads, especially through difficult terrain. When you prepare for your
journey, be aware of an increase in fuel consumption; the nearest filling station
may be far away.
Shifting gears correctly The gear you must shift into depends on the terrain. Choosing the correct gear
contributes to safe driving. In particular if you do not have much experience driv-
ing off-road, it is always better, before negotiating a difficult stretch of the road,
to pause and reflect on which gear to engage. Your experience will tell you which
gear is the best for certain sections of the terrain.
Basically:
● When the gear or the driving stage has been properly selected, it is unneces-
sary to slow down the vehicle on a downhill section using the footbrake as in
most cases the engine braking power is sufficient.
● Depress the accelerator only as much as is necessary. A too great acceleration
may lead to the wheels spinning and thus results in the loss over the control of
the vehicle. Manual gearbox
● If you are driving through difficult terrain, on no account use the clutch or
change the gear. When the clutch is depressed, the vehicle may come to a stand-
still because of the increased grip of all the tyres of the vehicle (e.g. in the mud, in
deep sand or on a slope). Once the vehicle has come to a standstill, it may be diffi-
cult or even impossible to start off under these conditions.
● When negotiating a steep downhill section or a steep uphill section, always
shift into the 1st or 2nd gear.
● On a soft or slippery ground, you must drive at the appropriate speed and you
must select the highest possible gear for this.
Automatic gearbox
● Select the selector lever position D for normal flat stretches of terrain
⇒ page 113.
● While in the Tiptronic mode, select the selector lever position 3 or
2 if you
are driving through mud, sand, water or hilly sections of terrain ⇒ page 115.
● When negotiating a steep downhill section or a steep uphill section, select the
selector lever position 1 while in the Tiptronic mode.
● On a soft or slippery ground, you must drive at the appropriate speed and you
must select the highest possible driving stage.
Driving over rough and smooth Fig. 148 Observe the ground clearance
– Switch on the Off-road mode ⇒ page 160 .
– Drive at walking speed over rocky passages.
– If it is not possible to drive around a stone, gently drive onto the stone with
one of the front wheels and then drive over it slowly. £172
Driving and the environment
WARNING
Observe the important guidelines ⇒ page 168. CAUTION
● On no account drive over large objects (such as pieces of rock or tree stumps),
neither in the middle nor on one side. When driving over objects which are larger
than the ground clearance, the chassis and its components can get damaged. Your
vehicle could break down far away from any assistance.
● Even objects that are smaller than the existing ground clearance can come in-
to contact with the underbody of the vehicle and can lead to damage or failure of
the vehicle. This applies especially when there is a hollow or soft ground in front
or behind the object or if you drive too fast over the object and thus the vehicle is
deflected. For the sake of the environment
Leaking engine oil and brake fluid pollute the environment and contaminate the
bodies of water. The disposal e.g. of engine oil soaked soil can be costly.
Crossing bodies of water Particular attention is required when driving through bodies of water
⇒
page 167.
Driving through snow-covered terrain –
Before you drive through snow-covered terrain, mount snow chains on the
front wheels or on the rear wheels ⇒ page 205, Snow chains in order to ach-
ieve the best possible traction.
– Switch on the Off-road mode ⇒ page 160
.
Even harmless looking sections of terrain can be dangerous. This applies in partic-
ular for sections where no ruts or other tracks are visible. WARNING
● Driving through snow-covered terrain poses special dangers. Never choose
a dangerous route and never take a risk which could jeopardize your safety
and that of your passengers. If you cannot go on or if you doubt the safety of
the route, turn back and choose another way.
● Potholes, troughs, trenches, precipices, sheets of ice or other obstructions
are often completely or partially obscured by snow.
● The hidden dangers of snow can cause an accident, serious injuries or your
vehicle to break down under extreme weather conditions.
Driving over steep terrain Driving uphill and downhill
–
Stop the vehicle before driving uphill or downhill, exit the vehicle and explore
the situation.
– Walk a stretch and check the firmness of the soil and look for obstructions or
other hidden dangers.
– Check how the route continues beyond the slope.
– Switch on the Off-road mode ⇒ page 160
.
– Drive slowly and steadily straight uphill or downhill.
– Do not stop the vehicle on a hillside or attempt to turn around.
– You must prevent the engine from cutting out.
Driving uphill
– Check before driving over a hilltop, how it continues on the other side. If you
drive up a steep hill, the vehicle faces the sky and you cannot see what is di-
rectly in front of the vehicle.
– Switch on the Off-road mode
⇒ page 160
.
– Do not shift gears or release the clutch during the climbing phase.
– Depress the accelerator only as much as is necessary in order to handle the
slope.
If you can go no further on a slope
– Never attempt to make a turn with the vehicle on a hillside.
– If the engine cuts out, press the foot brake and restart the engine. £ 173
Driving and the environment Using the system Safety Driving Tips General Maintenance Breakdown assistance Technical data
–
Engage the reverse gear and carefully drive backwards in your own tracks.
– Press the foot brake in order to maintain a constant speed.
Downhill
– Switch on the Off-road mode ⇒ page 160 .
– Shift into first gear or select the first driving stage, while in the Tiptronic
mode, to drive downhill on steep hillsides in order to use the Downhill Drive
Support to its maximum.
– Press the foot brake gently, so you do not lose the control over your vehicle.
– If it is feasible and safe, drive straight down (maximum gradient).
– Do not release the clutch or shift into Neutral. WARNING
● Never attempt to drive uphill or downhill if it is too steep for your vehicle.
The vehicle could slip or roll over - risk of accident!
● Never attempt to make a turn on a hillside. The vehicle could tilt or roll
over. This can result in serious accidents.
● If the engine cuts out on a slope or you can no longer go on for whatever
other reason, then stop!
● Never let the vehicle roll down the hillside at idling speed. You can lose the
control over your vehicle.
● If the engine cuts out, press the foot brake and restart the engine. Engage
the reverse gear and carefully drive backwards in your own tracks. Use the en-
gine braking power and press the foot brake in order to maintain a slow and
constant speed.
● Observe the important guidelines ⇒ page 168. Driving at an angle on a hillside Fig. 149 Steer and maintain your trajectory/in direction to exit - facing uphill
Driving at an angle on a hillside is one of the most dangerous situations while
driving off-road. It may look harmless, but you must never underestimate the diffi-
culties and the dangers when driving at an angle on a hillside. Basically you should
avoid moving your vehicle into a sideways position on a hillside. Under certain cir-
cumstances, the vehicle can slide away uncontrollably or roll over.
Check before driving in a tilted position, whether there is a different and safer
route. If you have to drive in a tilted position, then the ground should be as firm
and even as possible. Note that the vehicle may slide sideways or sink in and roll
over when driving on slippery or soft ground. Make sure that the inclination is not
too steep when driving over surface irregularities. Otherwise, the vehicle can roll
over and then roll down the hillside.
If the vehicle is at a very steep angle, the wheels on the low side must not sink
deeply into the ground or into troughs and you must not drive over stones, tree
stumps or other obstructions with the alternate raised wheels.
If there is a risk your vehicle may tilt, steer immediately in direction of dip
⇒ fig. 149 and lightly depress the accelerator. The centre of gravity of the vehicle
should be as low as possible. Distribute the weight of all the occupants of the ve-
hicle evenly. Taller and heavier people should be seated on the raised side of the
vehicle. The luggage on the roof should be removed and secured, as the vehicle
could tilt by a sudden shifting of the luggage.
A passenger, seated at the rear, should always remain seated on the seat facing
up the hill during such a journey. In an extreme case, the passenger on the rele-
vant side must exit the vehicle until you have safely crossed the hillside. £174
Driving and the environment
WARNING
● Combustible materials which are trapped under the vehicle floor can be
dangerous. They can impair the driving safety and the safety of all the occu-
pants of the vehicle. After driving off-road, always check the underside of the
vehicle and remove trapped objects.
● Never continue the journey if objects are trapped under the vehicle. This
can damage the fuel lines, the brake system, the seals and other parts of the
chassis.
● Combustible objects such as dry leaves or twigs could ignite on hot vehicle
parts. A vehicle fire can also lead to serious injuries.
● Observe the important guidelines ⇒ page 168. 177
Driving and the environment Using the system Safety Driving Tips General Maintenance Breakdown assistance Technical data