traction control AUDI A8 2015 Owners Manual

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Electronic Stabilization
Control (ESC)
Description
ESC helps to improve road holding and vehicle
dynamics to help reduce the probability of
skidd ing and loss of veh icle control. It works
only when the eng ine is running. ESC detects
certain difficult driv ing s ituations, including
when the vehicle is beginning to spin (yaw)
out of cont ro l and helps you to get the vehicle
back under control by select ively brak ing the
wheels, and/or red ucing engine powe r and
p roviding steering assistance to help hold the
ve hicle on the driver's intended course . The in­
dicator light
m in the instrument cluster
blinks when ESC is taking action to help you
control the vehicle.
ESC has limitations.
It is important to remem­
ber that ESC cannot overcome the laws of
phys ics. It will not a lways be able to help out
under all conditions you may come up against.
For example, ESC may not always be able to
h elp you master situat ions where there is a
sudden change in the coefficient of fr iction of
the road surface. When there is a sect io n of
d ry road that is s udden ly cove red with water,
slush o r snow, ESC canno t perform the same
way it would on the dry su rface.
If the vehicle
hydroplanes (rides on a c ush ion of wate r in­
stead of the road surface), ESC wi ll not be
ab le to he lp you steer the veh icle because con-
Int ellig ent technolog y 197
tact with the pavement has been interrupted
and the vehicle cannot be braked or steered .
D uring fast corner ing, particular ly on wind ing
roads, ESC cannot always deal as effectively
with difficult dr iv ing s ituations than at lower
speeds. When towing a trailer, ESC is not able
to help you regain control as it would if you
were not tow ing a trailer.
Always adjust your speed and driving style to road, traffic and weather conditions . ESC can­
not override the vehicle's physical lim its, in­
crease the availab le tract ion, or keep a veh icle
o n the road if road departu re is a result of
driver ina ttent io n. Instead , ESC imp roves the
poss ibility of keep ing t he vehicle under con­
trol and on the road during extreme maneu­
vers by using the driver's steering i nputs to
help keep the vehicle go ing in the intended di­
rect ion. If you are traveling at a speed that
causes you to run off the road before ESC can
provide any assistance, you may not experi­
ence the benefits of ESC.
ESC includes and/or works together with the
anti-lock braking system
(ABS), brake assist
system, anti -slip regulation (ASR), electronic
differential lock (EDL), dynam ic steer ing* and
selective wheel torque contro l. ESC is switch­
ed on all the time. In cer tain situations when
yo u need less traction, yo u can switch off ASR
by press ing the b utton above ~
page 199,
fig. 188 the se lector lever. Be sure to switch
ASR on again when you no longer need less
traction.
Anti -lock braking system (ABS )
ABS prevents the whee ls from loc king up
when b rak ing. The vehicle can st ill be stee red
even during hard braking . App ly steady pres­
su re to the brake peda l. Do not pump the ped­
al. A pulsing in the brake pedal indicates that
the system is helping you to brake the vehicle.
Brake assi st sy stem
T he brake ass ist system can dec rease braking
distance . It increases braking power when the
driver presses the brake peda l quickly in emer­
gency s ituations. You must press and hold the
brake pedal unti l the situation is over. In
I),
•
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202 Intelligent technology
Driving with your
quattro
With All Wheel Drive, all four wheels are driv­
en .
General inform ation
With All Wheel Drive, power is distributed to
all four wheels . This happens automatically
depending on your driving style and the road
conditions at the time . See also
c:;; page 197.
With the sport differential*, power d istribu­
tion to the rear wheels is variable and can be
adjusted with Audi d rive select*
c:;; page 108.
Always read and follow safety precautions
¢ .&,.
Winter tires
When driving in the winter , your vehicle with
A ll Wheel Drive has an advantage, even with
regular tir es. In winter road conditions it may
be advisable to mount winter tires (or all-sea­
son tires) for improved driveability and brak­ ing: these tires must be mounted on
all four
wheels.
See also ¢ page 260, Winter tires.
Snow chains
Where snow chains are mandatory on certa in
roads, this normally a lso applies to vehicles
with A ll Wheel Drive
c:;, page 261, Snow
chains .
Replacing wheels/tires
Vehicles with All Wheel Dr ive must always
have tires of the same size. Also avoid ti res
with different tread depths. For details see
page
c:;, page 256, New tires and replacing
tires and wheels .
Off-Road driving?
Your Audi does not have enough ground clear­
ance to be used as an off-road vehicle. It is
therefore best to avoid rough tracks and un ­
even terrain as much as possible. Also refer to
c:;; page207.
A WARNING
Always adjust your driving to road and traf­
f ic conditions. Do not let the extra safety
afforded by All Wheel Drive tempt you into
taking extra risks.
- Although the All Wheel Drive is very ef­
fective, always remember that braking
capacity is lim ited by tire traction. You
should therefore not drive at excessive
speeds on icy or slippery road surfaces.
- On wet road surfaces, be careful not to
drive too fast because the front wheels
could begin to slide on top of the water
(aquaplaning) . If this should occur, you
will have no warning from a sudden in­
crease in eng ine speed as with a front­
wheel drive vehicle. Always drive at speeds which are suited to the road con­
ditions - risk of crash .
Energy management
Starting ability is optimized
Energy management controls the distribution
of electrical energy and thus optimizes the
availability of electrical energy for starting
the engine .
If a vehicle with a conventiona l ene rgy system
is not driven for a long period of time, the bat­
tery is discharged by idling current consumers
(e .g. immobilizer). In certain circumstances it
can resu lt in there being insufficient energy
available to start the engine .
Intelligent energy management in your vehi­
cle handles the distribution of e lectrica l ener­
gy. Starting ability is markedly improved and
the life of the battery is extended.
Basically, energy management consists of
battery diagnosis , idling current manage­
ment
and dynamic energy management.
Battery diagnosis
Battery diagnosis continuously determines
the state of the battery. Sensors determine
battery voltage, battery current and battery ..,.

24 6 T ire s and whee ls
- Never mount used tires on yo ur vehicle if
you are not sure of their "previous histo­
ry." Old used tires may have been dam­
aged even though the damage cannot be
seen that can lead to sudden tire failure
and loss of vehicle control.
- If you notice unusual vibration or if the
vehicle pulls to one side when driving, al­
ways stop as soon as it is safe to do so and check the wheels and tires for dam­
age.
(D Note
- Please note that summer and winter
tires are designed for the cond itions that
a re typ ica l in those seasons. Aud i recom­
mends using w inter t ires d uring the win-
Glossary of tire and loading terminology
Accessory weight
means t he comb ined weight (in excess of
those standard items which may be rep laced)
of automatic transmission, power steering,
power brakes, power windows, power seats,
radio, and heater, to the extent that these
items are available as factory-installed equip­
ment (whether installed or not).
Aspect ratio
means t he ratio of the height to the width of
the tire in percent. Numbers of 55 or lower in­
d icate a low sidewall for improved steer ing re­
sponse and better overall handling on dry pavement .
Bead
means the pa rt of the tire t hat is made of
steel wires, wrapped or reinforced by ply cords
and that is shaped to fit the r im.
Bead separation
means a breakdown of the bond between
components in the bead.
Cord
means t he strands forming the plies in the
tire. ter months.
Low tempe ratu res signifi­
cantly decrease the elasticity of summer
tires, which affects traction and braking ability. If summer tires are used in very
co ld temperatures, cracks can form on
the tread bars, resu lting in permanent
tire damage that can cause loud driving noise and unbalanced tires. Aud i is not
responsib le for this type of damage.
- Burn ished, polished or chromed rims
must not be used in winter weather. The
surface of the rims does not have suff i­
c ien t corrosion protect io n for this and
cou ld be pe rmanently damaged by road
salt or simi lar substances. This damage
is not covered by war ranty.
Cold tire inflat ion pre ssure
means the t ire press ure recommended by the
vehicle manufacturer for a tire o f a des ignated
size that has not been driven for more than a
coup le of miles (ki lometers) at low speeds in
the three hour period before the tire press ure
is measured or adjusted.
Curb weight
means the weight of a motor vehicle w ith
standard equipment including the maximum
capacity of fuel, o il, and coolant, air cond i­
tion ing and additional weight of optiona l
equipment.
E x tra load tire
means a tire design to operate at higher loads
and at higher inflation pressures than the cor­
responding standard tire. Extra load tires may
be identified as "XL", "xl", "EXTRA LOAD", or
"RF" on the sidewall.
Gross A xle Weight Rating ("GAWR ")
means the load-carrying capacity of a single
axle system, measured at the tire-ground in -
terfaces.
IJ>,

256 Tires and wheels
Incorrect wheel alignment
Incorrect wheel alignment can cause exces­
sive tire wear, impairing the safety of the vehi­
cle. If tires show excessive wear, have the
wheel alignment checked by an authorized
Audi dealer or qualified workshop.
All Wheel Drive
Vehicles with quattro must always have tires
of the same size, construction and tread type.
For details see Qpage 202 .
.&_ WARNING
Sudden tire failure can lead to loss of con­
trol, a crash and serious personal injury!
- Never drive a vehicle when the tread on
any tire is worn down to the wear indica­
tors.
- Worn tires are a safety hazard, they do
not grip well on wet roads and increase
your risk of"hydroplaning" and loss of
control.
- Always keep chemicals that can cause
tire damage, such as grease, oil, gasoline
and brake fluid away from tires.
- Tires age even if they are not being used
and can fail suddenly, especially at high
speeds. Tires that are more than 6 years
old can only be used in an emergency
and then with special care and at lower speeds.
- Never mount used tires on your vehicle if
you are not sure of their "previous histo­
ry." Old used tires may have been dam­
aged even though the damage cannot be
seen that can lead to sudden tire failure
and loss of vehicle control.
New tires and replacing tires and wheels
New tires and wheels have to be broken in .
Fig. 212 Tir e specificat ion codes on the s idewall of a
t ire
No. Description
@ Nominal width of tire in millimeters
® Ratio of height to width (aspect ratio)
© Radial
® Rim diameter code
® Load index and speed rating
(J) U.S . DOT tire identification number
® Audi Original tire
® Sever snow conditions
@ Tire ply composition and materials
used
@ Maximum load rating
@ Treadwear, traction and temperature
grades
@ Maximum permissible inflation pres-
sure
The tires and rims are essential parts of the
vehicle's design . The tires and rims approved
by Audi are specially matched to the charac­
teristics of the vehicle and can make a major .,..

258 Tires and wheels
T up to 118 mph (190 km/h)
U up to 124 mph (200 km/h)
H up to 130 mph (210 km/h)
V up to 149 mph (240 km/h)
1l
Z over 149 mph (240 km/h)ll
W up to 168 mph (270 km/h)ll
Y up to 186 mph (298 km/h)l)
Your veh icle is normally factory equipped with
tires, which possess excellent driving charac­
teristics and give your Audi opt imum driving
comfort. An electronic speed limiter
c:> page 30 will normally prevent your vehicle
from going faster than the tire speed rating
c:> & .
U.S . DOT Tire Identification Number (TIN)
and tire manufacture date
This is the tire's "serial number". It begins
with the letters "DOT" and indicates that the
tire meets all federal standards. The next two
numbers or letters indicate the plant where it
was manufactured, and the last four numbers
r epresent the week and year of manufacture.
F or example, the numbers 2214 mean the tire
was produced in the 22nd week of 2014. The
other numbers are marketing codes that may
or may not be used by the tire manufacturer .
T his information is used to contact consumers
if a tire defect requires a recall.
Audi original tire
Tires with the identification "AO" or "RO" have
been specially matched with your Audi . We
recommend using only these tires because
they meet the highest standards regarding
safety and driving characteristics when used
correctly . Your authorized Audi dealer will
gladly provide you with more information .
Tire ply composition and materials used
The number of plies indicates the number of
layers of rubber-coated fabric in the tire. In
general, the greater the number of plies, the more weight a tire can support. Tire manufac -
ll F t· "t h .
o r ires w 1 a m ax im um spee d ca pabil ity ove r 149
mph (2 40 km/ h), ti re manufact urers sometimes use
the lett ers " ZR."
turers also must indicate the materials in the
tire, which include steel, nylon, polyester, and
others .
Maximum Load Rating
Th is number ind icates the max imum load in
kilograms and pounds that can be carried by
the tire .
Tire quality grading for treadwear,
traction , and temperature resistance
Tread wear, traction and tempera ture grades
c:>page 259.
Maximum Permissible Inflation Pressure
This number is the greatest amount of a ir
pressure that should ever be put in the tire
un der normal driv ing conditions .
_& WARNING
= -
- Using incorrect or unmatched tires and/
or wheels or improper tire and wheel
combinations can lead to loss of control
collision and serious personal injury.
'
- Always use tires, rims and whee l bolts
that meet the specifications of original factory-installed tires or other combina­
tions that have been specifically ap­
proved by the vehicle manufacturer.
- Tires age even if they are not being used
and can fail suddenly, especially at high
speeds. Tires that are more than 6 years
old can only be used in an emergency
and then w ith special care and at lower
speeds.
- Never mount used tires on your veh icle if
you are not sure of the ir "previous histo­
ry." Old used tires may have been dam­
aged even though the damage cannot be
seen that can lead to sudden tire fa ilure
and loss of vehicle control.
- All four whee ls must be fitted with radial
tires of the same type, size (rolling cir­ cumference) and the same tread pattern . ..,_

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Driving with different tires reduces vehi­
cle handling and can lead to a loss of
control.
- If the spare tire is not the same as the
tires that are mounted on the vehicle -
for example with winter tires -only use
the spare tire for a short period of time and drive with extra care. Refit the nor­
mal road wheel as soon as safely possi­
ble.
- Never drive faster than the maximum
speed for which the tires on your vehicle
are rated because tires that are driven
faster than their rated speed can fail
suddenly.
- Overloading tires cause heat build-up,
sudden tire failure, including a blowout
and sudden deflation and loss of control.
- Temperature grades apply to tires that
are properly inflated and not over or un­
deri nflated.
- For technical reasons it is not always
possible to use wheels from other
vehicles -in some cases not even wheels
from the same vehicle model.
- If you install wheel trim discs on the ve­
hicle wheels, make sure that the air flow
to the brakes is not blocked. Reduced air­
flow to the brakes can them to overheat, increasing stopping distances and caus­
ing a collision.
- Run flat tires may only be used on
vehicles that were equipped with them at the factory . The vehicle must have a
chassis designed for run flat tires. Incor­
rect use of run flat tires can lead to vehi­
cle damage or accidents. Check with an
authorized Audi dealer or tire specialist
to see if your vehicle can be equipped
with run flat tires. If run flat tires are used, they must be installed on all four
wheels. Mixing tire types is not permit­
ted.
(D Note
- For technical reasons, it is not generally
possible to use the wheel rims from oth-
Tires and wheels 259
er vehicles. This can hold true for wheels
of the same vehicle type.
- If the spare tire is different from the
tires that you have mounted on your ve­
hicle (for example winter tires or wide
profile tires), then use the spare tire for a
short period of time only and drive with
extra care. Replace the flat tire with the
tire matching the others on your vehicle
as soon as possible.
- Never drive without the valve stem cap .
The valves could get damaged .
(® For the sake of the environment
Dispose of old tires in accordance with the
local requirements.
Uniform tire quality grading
-Tread wear
- Tract ion AA A B C
- Temperature AB C
Quality grades can be found where applicable
on the tire side wall between tread shoulder
and maximum section width
c;, page 256,
fig. 212.
For example: Tread wear 200, Traction AA,
Temperature A.
All passenger car tires must conform to Feder­
al Safety Requirements in addition to these
grades.
Tread wear
The tread wear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
government test course.
For example, a tire graded ISO would wear
one and one half (11/2) times as well on the
government course as a tire graded 100.
The relative performance of tires depends upon the actual conditions of their use, how­
ever, and may depart significantly from the
norm due to variations in driving habits, serv­
ice practices and differences in road character-
istics and climate.
ll-
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260 Tire s and wheel s
Traction
The traction grades, from highest to lowest,
are AA, A, Band
C. T hose grades represent the
tire's ability to stop on wet pavement as
measured under controlled conditions on
specified government test surfaces of asphalt
and concrete. A tire marked C may have poor
traction performance
c:> .&. .
Te mp eratu re
The temperature grades are A (the highest),
B, and
C, representing the t ire's resistance to
the generat ion of heat and its ability to dissi­
pate heat when tested under con trolled cond i­
tions on a specified i ndoor laboratory test
wheel.
Sustained high temperature can cause the material of the tire to degenerate and reduce
tire life, and excessive temperature can lead
to sudden tire failure
c:> ,& .
The grade C corresponds to a level of perform­
ance which all passenger car tires must meet under the Federa l Motor Veh icle Safety Stand­
ard No . 1 09 . Grades Band A represent h igher
l eve ls of pe rformance on the laboratory test
wheel than the m inimum required by law.
.&_ WARNING
T he traction grade assigned to this t ire is
based on stra ight-ahead braking traction
tests, and does not include acceleration,
cornering, hydrop laning o r peak traction
character istics.
A WARNING
The temperature grade for this t ire is es ­
tablished for a t ire that is properly inflated
and not ove rloaded. Excessive speed, un­
derinflation, or excessive loading, either
separately or in combination, can cause
heat buildup and possible ti re fa ilu re.
-
Winter tires
Winter tires can improve vehicle handling on
snow and ice . At temperatures below 45 °F
(7 °C) we recommend changing to winter
tires.
In some heavy snow areas, local governments
may require true w inter o r "snow" t ires , those
with very deeply cut tread . Th ese tires should
o n ly be used in pairs and be installed on a ll
f o ur wheels . Make sure you p urch ase snow
t ir es that are the same size and cons truction
type as the othe r tires on yo ur vehicle.
If your vehicle i s equ ipped w ith all-whee l
drive, this will improve tra ction during w inte r
driv ing, even with the standard tires . Howev ­
er, we strongly recommend that you always
equip all four wheels on your vehicle w ith cor­
rect ly fitted winter tires or all-season t ires,
when winter road condit ions are expected.
This also improves the veh icle 's brak ing per­
formance and reduces stopping d istances .
Summer tires provide less grip on ice and
snow.
Winter tires (snow tires) must always be fitted on all fo ur whee ls .
As k your au thori zed A udi dealer or qualified
workshop for permit ted
winter tire size s. Use
only radial winter tires .
Winter tires lose their effec tivenes s whe n the
tread is wo rn down to a depth o f 0 .1 57 inch
(4 mm) .
Only d rive w ith w inter t ires under w inte r co n­
di tions. S umme r tir es handle be tte r whe n
the re is no snow o r ice on the roa ds an d the
temperatu re is above 45 °F (7 °C) .
If you have a flat ti re, see notes on spare
whee l
c:> page 256.
Please a lways remember that winter tires may
have a lowe r speed rating than the tires o rigi­
nally i nstalled on your vehi cle at the time it
was manuf actu red. P lease see
c:> page 257,
Speed ra ting (Letter code) fo r a lis ting o f the
speed rating lette r codes and the max imum
speed at which the tires can be driven . ..,.