Automatic gearbox
101
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
A time delay element ensures that the selector lever is not blocked when rapidly switching over the position
N (e.g. from
R to D). This does, for example, allow one to
seesaw out a stuck vehicle. The selector lever lo
ck will click into place if the lever is in
the
N position for more than 2 seconds without the brake pedal being pressed.
The selector lever lock is only active if the
vehicle is stationary or
moving at speed of
less than 5 km/hour. The lock is swit
ched off automatically into position
N when the
car is travelling at a higher speed. Shiftlock button The Shiftlock button in the hand
le of selector lever prevents certain selector lever posi-
tions being engaged inadvertently. The selector lever lock is cancelled when you press the Shiftlock button. Keylock
8)- Ignition key withdrawal lock
You can only withdraw the ignition key after switching off the ignition if the selector lever is in position
P. If the ignition key is withdrawn, the selector lever is blocked in
position
P.
Kickdown function The kickdown function provides you with maximum acceleration power.Fully depressing the accelerator pedal allows
the kickdown function to be activated in
the desired driving program. This function has precedence over the driving programme and serves for maximum acceleration of the vehicle when exploiting the maximum power potential of the engine wi
thout taking into account the current
selector lever position (
D, S or Tiptronic
). The gearbox shifts down to one or several
gears in line with the driving state and the vehicle accelerates. The gearbox does not shift up into the highest gear until the en
gine has reached its maximum revolutions for
this gear range.
WARNING
Please note that using the kickdown function can result in the driven wheels spinning on a smooth or slippery road surface - risk of skidding!
Dynamic shift programmeThe automatic gearbox of your vehicle is
controlled electronically. Shifting up and
down through the gears is performed automatically on the basis of pre-defined driving programmes. Adopting a
moderate style of driving
will cause the gearbox to select the most
economical driving programme. Shifting up into a higher gear as soon as possible and shifting down as late as po
ssible will have a favourable effect on your fuel consump-
tion. Adopting a
sporty style of driving
with rapid movements of the accelerator pedal
combined with sharp acceleration and freque
nt changes in speed, exploiting the top
speed of the car or depressing the accele
rator pedal (kickdown function), will cause
the gearbox to switch over to this style of driving and shift down earlier with frequent changes in gears in comparison to the moderate style of driving. Selecting the most appropriate driving programme for the particular style of driving is a continuous process. Irrespective of this it is, however, possible to switch or shift down into a dynamic shift programme by depressi
ng the accelerator rapidly. The gearbox
shifts down into a lower gear matching the speed of the car and this allows you to accelerate rapidly (e.g. when overtaking)
without having to depress the accelerator
pedal fully into the kickdown range. The or
iginal programme will be reactivated to
match your particular styl
e of driving once the gearbox has shifted up again.
When driving in hilly regions, the gears are selected to match uphill and downhill sections. This avoids the gearbox frequently
shifting up and down when negotiating an
uphill stretch. When driving downhill, it is
possible to shift do
wn into the Tiptronic
position, in order to exploit the engine brake torque.
8)Only valid for some countries.
s3j8.a.book Page 101 Tuesday, April 20, 2010 1:10 PM
Automatic gearbox
102
Tiptronic The Tiptronic allows the driver
to also shift gears manually.
Fig. 101 Selector lever: manual shifting / large information display: manual shiftingThe selector lever position you have engaged is indicated in the information display of the instrument cluster together with the engaged gear
fig. 101
on the right.
Switching over to manual shifting– Push the selector lever to the right out of position
D. After switching over, the
current engaged gear is indicated in the display.
Shifting up gears– One-touch forward of the selector
lever (in the Ti
ptronic position)
fig. 101
.
Shifting down gears– One-touch back of the selector lever (in the Tiptronic position) . It is possible to switch over to manual both
when the car is stat
ionary and also when
driving. When you accelerate, the gearbox shifts up
automatically into the higher gear just
before the maximum permissible engine speed is reached. If you select a lower gear, the automatic gearbox does not shift down until there is no risk of the engine overrevving. If you operate the kickdown function, the gearbox shifts into a lower gear in line with the vehicle speed and engine speed.
Manual shifting on the multifunction steering wheel*Switching over to manual shifting– Push the selector lever to the right out of position
D. After switching over, the
current engaged gear is indicated in the display.
Shifting up gears– Press the right rocker switch
fig. 102
for the multifunction steering wheel.
Shifting down gears– Press the left rocker switch
fig. 102
for the multifunction steering wheel.
Temporarily switching over to manual shifting– If the selector lever is in position
D or S, press the left rocker switch or the right
rocker switch for the multifunction steering wheel.
– If the rocker switches or are not pr
essed for some time, the manual shifting
switches off. You can also switch off the
temporary switch over to manual shifting
by pressing the right
rocker switch for more than 1 second.
Emergency programme An emergency programme exists in the event of a fault in the system.The gearbox operates in a corresponding emergency programme if there are func- tional faults in the gearbox electronics. This
is indicated by all of
the segments in the
display lighting up or going out.
A+
A-
Fig. 102 Multifunction steering wheel: manual shifting
+-
-
+
-
+
+
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Intelligent Technology
137
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
Driving TipsIntelligent TechnologyElectronic stability programme (ESP)*GeneralGeneral The ESP aids you in maintaining control of
your vehicle in situations in which the
vehicle is driving at its dynamic limits, such as
entering a curve fast. The risk of skidding
is reduced and your vehicle thus offers greater driving stability depending on the conditions of the road surface. The system operates at all speeds. The following systems are integrated into the electronic stability programme:
Electronic Differential Lock (EDL);
Traction control system (TCS);
Antilock brake system (ABS);
Brake Assist;
Uphill Start Assist.
Operating principle The ESP switches on automati
cally when the engine is started and then conducts a
self-test. The ESP control unit processes data from the individual systems. It also proc- esses additional measurement data which are supplied by highly sensitive sensors: the rotational velocity of the vehicle about its ve
rtical axis, the lateral acceleration of the
vehicle, the braking pressure and the steering angle. The direction which the driver wishes to take is determined based on the steering angle and the speed of the vehicle and is co
nstantly compared wi
th the actual behav-
iour of the vehicle. If differences exist, such
as the vehicle beginning to skid, the ESP will
automatically brake the appropriate wheel. The car is stabilised again by the forces wh
ich take effect when the wheel is braked.
Intervention into the brake system takes place primarily on the outer front wheel of a vehicle which tends to oversteer (tendency fo
r the rear of the vehicle to break away)
while occurs this is on the inner rear wh
eel of a vehicle whic
h tends to understeer
(tendency to shift out of the curve). This braking control cycle is accompanied by noises. If the ESP helps to stabilise the vehicle (f
or example when applying and releasing a
braking force to an individual wheel), then the indicator light
flashes.
The ESP system cannot be switched off, only
the TCS system can be switched off by
pressing the button
page 138, fig. 130
. The warning light
page 31 lights up if
the TCS system is switched off. The warning light
lights up permanently if there is a fault in the ESP system.
The fact that the ESP system operates together with the ABS means that the ESP warning light will also come on if the ABS system is not operating properly. If the warning light
comes on immediately after starting the engine, the ESP system
can be switched off for technical reasons. In
this case, the ESP system can be switched
on again by switching the igni
tion on and off. If the warning light goes out, the ESP
system is fully functional again.
WARNING
It is also not possible for the ESP to overcome the physical limits of the vehicle. Even if a vehicle fitted with ESP you should still always adapt your style of driving to the condition of the road surfac
e and the traffic situation. This partic-
ularly applies when driving on slippery
and wet roads. The increased safety
offered must not tempt you to take greater risks than otherwise - risk of an acci- dent!
Note
All four wheels must be fitted with the same tyres in order to achieve problem-free
operation of the ESP. Differing rolling circum
ferences of the tyres can lead to an unde-
sirable reduction in the engine output.
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Intelligent Technology
138
Changes to vehicle (e.g. on engine, on th
e brakes, on chassis or another combina-
tion of tyres and wheels) can influence the function of the ESP
page 184, “Accesso-
ries, changes and replacement of parts”.Traction control system (TCS)* The traction control system prevents the driven wheels from spinning when accelerating.General The TCS makes it much easier, and sometimes at all possible, to start off, accelerate and climb a steep hill when the conditions
of the road surface are unfavourable.
Operating principle The TCS switches on automatically when th
e engine is started and then conducts a
self-test. The system monitors the speeds of the driven wheels with the aid of the ABS sensors. If the wheels are spinning, the force transmitted to the road surface is auto- matically adapted by reducing the engine speed. The system operates at all speeds. The TCS operates in combination with the ABS
page 140, “Antilock brake system
(ABS)”. The TCS will not function if a fault exists in the ABS system. The TCS warning light lights up in the instru
ment cluster when there is a fault on the
TCS
page 31.
Switching off You can switch the TCS off and on agai
n as you wish by pressing the button
fig. 130
.
The TCS warning light lights up in the instrument cluster when the TCS is switched off page 31.
The TCS should normally always
be switched on. It may be good practice in certain
exceptional cases, such as when you wish to
have wheel slip, to switch off the system.
Examples:
when driving with snow chains;
when driving in deep snow or on a loose surface;
when it is necessary to rock a vehicle when it has become stuck.
then you should switch on the TCS again.
WARNING
You should always adjust your style of driving to the conditions of the road surface and the traffic situation. The increased safety offered must not tempt you to take greater risks than otherwise - risk of an accident!
Note
All four wheels must be fitted with the same tyres in order to achieve problem-free
operation of the TCS. Differing rolling circum
ferences of the tyres can lead to an unde-
sirable reduction in the engine output.
Changes to vehicle (e.g. on engine, on the brakes, on chassis or another combina-
tion of tyres and wheels) can influence the function of the TCS
page 184, “Accesso-
ries, changes and replacement of parts”.Electronic Differential Lock (EDL)* The electronic differential lock prev
ents an individual wheel from slip-
ping.Models fitted with ESP are equipped with
electronic differential lock (EDL).
Fig. 130 TCS switch
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Intelligent Technology
139
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
General The EDL makes it much easier, and sometimes
at all possible, to start off, accelerate
and climb a steep hill when the conditions of the road surface are unfavourable. Operating principle The EDL is activated automaticall
y, that is without any action on the part of the driver.
It monitors the speeds of the driven wheels with the aid of the ABS sensors. Should only
one
drive wheel begin spinning on a slippery surface there will be an appreciable
difference in the speed of the driven wheels. The EDL function brakes the slipping wheel and the differential transmits a greate
r driving force to the other driven wheel.
This control process is also accompanied by noises. Overheating of the brakes The EDL switches off automatically if unusually severe stresses exist in order to avoid excessive heat generation in the disc brake on the wheel which is being braked. The vehicle can continue to be driven and has
the same characteristics as a vehicle not
fitted with EDL. The EDL switches on again automatically as soon as the brake has cooled down.
WARNING
Carefully depress the accelerator when accelerating on uniformly slippery
road surfaces, such as ice and snow. The driven wheels might still spin despite the EDL and affect the stability of
the vehicle - risk of an accident!
You should always adapt your style of driving to the condition of road
surface and to the traffic situation even
when your vehicle is fitted with EDL.
The increased safety offered must not tempt you to take greater risks than otherwise - risk of an accident!
Note
If the ABS or TCS or ESP warning light comes on, this may also indicate a fault in the
EDL. Please have the vehicle inspected as
soon as possible by a specialist garage.
Changes to vehicle (e.g. on engine, on th
e brakes, on chassis or another combina-
tion of tyres and wheels) can in
fluence the function of the EDL
page 184, “Accesso-
ries, changes and replacement of parts”.
BrakesWhat has a negative effect on braking efficiency?Wear-and-tear Wear-and-tear to the brake pa
ds is greatly dependent on
the operating conditions of
the vehicle and your style of driving. Particularly if you drive a great deal in towns and over short distances or if you adopt a sporty
style of driving, it may be necessary to
have the thickness of the brake pads insp
ected at a specialist garage between the
service inspections. Wet roads or road salt There may be a certain delay before the brakes
take full effect un
der certain conditions
such as when driving through water, during
heavy rain showers or
after the vehicle has
been washed in an automatic vehicle wash
, since the brake discs and brake pads may
be moist or even have a coating of ice on them in winter. You should dry the brakes as soon as possible by applying and
releasing the brakes several times.
There also may be a certain delay before the
full braking efficiency is available when
driving on roads which have been treated with
road salt if you have not used the brakes
for some considerable time beforehand. The
layer of salt on the brake discs and brake
pads must first be rubbed off when you apply the brakes. Corrosion Corrosion on the brake discs and dirt on th
e bake pads occur if
the vehicle has been
parked for a long period and if you do
not make much use of the braking system.
We recommend cleaning the brake discs by firm
ly applying the brakes at a fairly high
speed if you do not make much use of the braking system or if surface corrosion is present
.
Faults in the brake surface If you notice that the braking distance has
suddenly become longer and that the brake
pedal can be depressed further, it is possib
le that a brake circuit of the dual-circuit
brake system has failed. Drive, in such cases, to the nearest specialist garage without delay in order to have the problem rectified. Drive at a reduced speed while on your way to the dealer and adapt your style of
driving to the higher brake pedal pressure
required.
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Intelligent Technology
140
Low brake fluid level An insufficient level of brake fluid may result in problems in the brake system. The level of the brake fluid is monitored electronically
page 32, “Brake system
”.
WARNING
Only apply the brakes for the purpose of
drying and cleaning the brake discs
if the traffic conditions permit this. Do not place any other road users in jeop-ardy.
When retrospectively mounting a front spoiler, solid wheel hubs etc. one
must ensure that the air supply to the
front wheel brakes is not reduced other-
wise the braking system could run too hot.
Allow for the fact that new brake pads
do not achieve their full braking effi-
ciency until approximately
200 kilometres. New brake pads must be first “run
in” before they develop their optimal friction force. You can, however, compen- sate for this slightly reduced braking force by increasing the pressure on the brake pedal. This guideline also applie
s to any new brake pads installed at a
future date.
Caution
Never allow the brakes to rub by applying sl
ight pressure if you do not wish to brake
the vehicle. This causes the br
akes to overheat and can also result in a longer braking
distance and excessive wear.
Before negotiating a steep downhill sectio
n, please reduce your speed and shift
down into the next lower gear (manual gear
box) or select a lower driving stage (auto-
matic gearbox). This enables
you to make full use of the braking power of the vehicle
and reduces the strain on the brakes. Any ad
ditional braking should be done intermit-
tently, not continuously.
Note
The brake light flashes automatically in case
of an emergency braking at speeds greater
than 60 km/h or with the intervention of th
e ABS, which lasts longer than 1.5 seconds.
After the speed was reduced below 10 km/h or the vehicle was stopped, the brake light stops flashing and the hazard warning light system switches on. The hazard warning light system is switched off automatically
after accelerating
or driving off again.
Brake boosterThe brake booster boosts the pressure whic
h you generate with the brake pedal. The
necessary pressure is only genera
ted when the engine is running.
WARNING
Never switch off the engine befo
re the vehicle is stationary.
The brake booster only operates when the engine is running. Greater phys-
ical effort for braking is required when en
gine is switched off.
Because if you do
not stop as normal, this can cause an accident and severe injuries.Antilock brake system (ABS)ABS prevents the wheels locking when braking.General The ABS contributes significan
tly to enhancing the active
safety of your vehicle.
Compared to a vehicle not fitted with the ABS brake system, you are able to retain optimal steering ability even during a full br
ake application on a slippery road surface
because the wheels do not lock up. You must not expect, however, that the braking distance will be shorter under all circumstances as a result of the ABS. The
braking distance for example on gravel and
fresh snow, when you should anyway be driv
ing slowly and cautiously, will be longer.
Operating principle As soon as the vehicle speed has increased to about 20 km/hour an automatic test procedure is conducted during which you wi
ll be able to hear a pumping noise for
about 1 second. The brake pressure will be reduced on a wheel which is rotating at a speed which is too low for the speed of the vehicle and tending
to lock. This control
cycle is noticeable
from a
pulsating movement of the brake pedal
which is accomp
anied by noises.
This is consciously intended to provide the driver with the information that the wheels are tending to lock (ABS control range). You must always keep the brake pedal depressed to enable the ABS to optimally control the brake application in this braking range. Never interrupt the application of the brakes!
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Intelligent Technology
141
Using the system
Safety
Driving Tips
General Maintenance
Breakdown assistance
Technical Data
WARNING
The ABS can also not overcome the physical
limits of your vehicle. Please do
not forget this, particularly when driving on icy or wet road surfaces. If the ABS is operating within the control range,
adapt your speed immediately to the
conditions of the road surface and the traffic situation. The increased safety offered by the ABS must not tempt you to take greater risks than otherwise - risk of an accident!
The normal braking system is
still fully functional if there is an ABS fault.
Visit a specialist garage immediately and
adjust your style of driving according
to the damage to the ABS as you will no
t know how great the damage is and the
limitation it is placing on the braking efficiency.
Note
A warning light comes on if a fault occurs in the ABS system
page 32.
Changes to vehicle (e.g. on engine, on th
e brakes, on chassis or another combina-
tion of tyres and wheels) can in
fluence the function of the ABS
page 184, “Accesso-
ries, changes and replacement of parts”.Brake Assist*During a severe brake application (e.g. if a hazard exists), the Brake Assist increases the braking force and thus makes it possible to
rapidly produce the pressure required in
the brake system. The majority of drivers do apply the brakes
in good time in dangerous situations, but
do not depress the brake pedal with sufficient pressure. Consequently, it is not possible for the vehicle to achieve its maximum deceleration and the vehicle covers a greater distance than necessary. The Brake Assist is activated by the very quick operation of the brake pedal. In such cases, a much greater braking pressure exists
than during a normal
brake application.
This makes it possible, even with a relative
ly low resistance of the brake pedal, to
produce an adequate pressure in the brake system in the shortest possible time, which is required for maximum deceleration of th
e vehicle. You must apply the brake pedal
firmly and hold it in this position in order to achieve the shortest possible braking distance.
The Brake Assist is able to help you achi
eve a shorter braking distance in emergency
situations by rapidly producing the pressure required in the brake system. It fully exploits the attributes of the ABS. After you release the brake pedal, the function of the Brake Assist is automatically switched off
and the brakes operate in the normal way.
The Brake Assist is part of the ESP system. If
a fault occurs in the ESP, the Brake Assist
function is also not available.
Further information on the ESP
page 137.
WARNING
The Brake Assist is also not able to overcome the physical limits of your
vehicle in terms of the braking distance required.
Adapt your speed to the conditions of the road surface and to the traffic situ-
ation.
The increased safety offered by the Brake Assist must not tempt you to take
a greater safety risk than otherwise.Uphill Start Assist*The uphill start assist makes it easier to start off on steep hills. The system assists a start off by holding the brake pressure produced
by the brake pedal actuation for approx. 2
seconds after releasing the brake pedal. The driver can therefore move his foot from the brake pedal to the accelerator pedal and
start off on the slope, without having to
actuate the handbrake. The brake pressure drops gradually the more you operate the accelerator pedal. If the vehicle does not start
off within 2 seconds, it starts to roll back.
The uphill start assist is active as of a 3% slope, if the driver door is closed. It is always active on slopes when in forward or reverse start off. When driving downhill, it is inactive.Electrohydraulic power steeringThe power steering enables you to steer the vehicle with less physical force. The steering characteristics can be changed by a specialist garage.
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Intelligent Technology
142
You will place great stresses on the power steering system if the steering is turned to full lock when the vehicle is stationary. Turn
ing the steering to full lock in such a situa-
tion will be accompanied by noises. It is still possible to fully steer the vehicle if the power steering fails or if the engine is not running (vehicle being towed in). The only
difference is that gr
eater physical effort
is required. It is possible that the hydraulic pump of
the power steering will not run due to the low
vehicle network voltage if the battery has gone flat and the engine must started with the help off jump leads. This condition will
be indicated by lighti
ng up of the warning
light. The power steering operates again if the ba
ttery is charged to a specific range when
engine is running. It also op
erates again, if the engine
can be started with its own
battery. If there is a fault in the power steering, the warning light lights up in the instrument cluster
page 26.
Caution
Do not leave the steering at full lock fo
r more than 15 seconds when the engine is
running - risk of damagi
ng the power steering!
Note
Have the steering inspected as soon as possible by a specialist garage if there is a leak or fault in the system.
Tyre pressure monitoring system*The tyre pressure monitoring system compares with the aid of the ABS sensors the speed and also the rolling circumference of the individual wheels. If the tyre inflation pressure is significantly changed and thus the rolling circumference of a wheel, the warning light
lights up in the instrument cluster
page 31. The tyre pressure moni-
toring system functions late or too sensitively if:
the structure of the tyre is damaged,
the vehicle is loaded to one side or with a load on the roof,
the wheels of an axle are loaded heavily (e.g. when towing a trailer or when driving
uphill or downhill),
the vehicle is operated in unfavourable wi
nter conditions or
on an unfirm ground,
snow chains or emergency wheel* are mounted,
the driver has a sporty style of driving (with sharp acceleration and high speed
when cornering). Basic setting of the system After changing the tyre inflation pressures
or after changing one or several wheels, a
basic setting of the system mu
st be carried
out as follows.
Inflate all tyres to the specified inflation pressure
page 178.
Switch on the ignition.
Press button
fig. 131
for more than 2 seconds. While pressing the button,
the warning light
lights up. At the same time the basic values are stored, which is
confirmed with an acoustic sound and then the warning light
goes out.
Fig. 131 Button for setting the tyre inflation pressure control value
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