wheel AUDI TT ROADSTER 2019 Service Manual

8S8012721BA
Airbag system


from the airbag as possible. The backrest
must be adjusted to an upright position.
Make sure that the PASSENGER AIR BAG
OFF %; light comes on and stays on all the
time whenever the ignition is switched on.


ZA WARNING
If the PASSENGER AIR BAG OFF %; light does
not go out when an adult is sitting on the
front passenger seat after taking the steps
described above, have the airbag system in-
spected by your Audi dealer before transport-
ing anyone on the front passenger seat.

@ Tips
If the capacitive passenger detection system
determines that the front passenger seat is
empty, the frontal airbag on the passenger
side will be turned off, and the PASSENGER
AIR BAG OFF 3; light will stay on.
Repair, care and disposal of the airbags
Parts of the airbag system are installed at many
different places on your Audi. Installing, remov-
ing, servicing or repairing a part in an area of the
vehicle can damage a part of an airbag system
and prevent that system from working properly
in a collision.
There are some important things you have to
know to make sure that the effectiveness of the
system will not be impaired and that discarded
components do not cause injury or pollute the
environment.

ZA WARNING
Improper care, servicing and repair proce-
dures can increase the risk of personal injury
and death by preventing an airbag from de-
ploying when needed or deploying an airbag
unexpectedly:
— Never cover, obstruct, or change the steer-
ing wheel horn pad or airbag cover or the in-
strument panel or modify them in any way.
— Never attach any objects such as cup holders
or telephone mountings to the surfaces cov-
ering the airbag units.


— For cleaning the horn pad or instrument
panel, use only a soft, dry cloth or one mois-
tened with plain water. Solvents or cleaners
could damage the airbag cover or change
the stiffness or strength of the material so
that the airbag cannot deploy and protect
properly.
— Never repair, adjust, or change any parts of
the airbag system.
— All work on the steering wheel, instrument
panel, front seats or electrical system (in-
cluding the installation of audio equipment,
cellular telephones and CB radios, etc.)
must be performed by a qualified technician
who has the training and special equipment
necessary.
— For any work on the airbag system, we
strongly recommend that you see your au-
thorized Audi dealer or qualified workshop.
— Never modify the front bumper or parts of
the vehicle body.
— Always make sure that the side airbag can
inflate
without interference:
— Never install seat covers or replacement
upholstery over the front seatbacks that
have not been specifically approved by Au-
di.
— Never use additional seat cushions that
cover the areas where the side airbags in-
flate.
— Damage to the original seat covers or to
the seam in the area of the side airbag
module must always be repaired immedi-
ately by an authorized Audi dealer.
— The airbag system can deploy only once. Af-
ter an airbag has been deployed, it must be
replaced with new replacement parts de-
signed and approved especially for your Audi
model version. Replacement of complete
airbag systems or airbag components must
be performed by qualified workshops only.
Make sure that any airbag service action is
entered in your Audi Warranty & Mainte-
nance booklet under AIRBAG REPLACEMENT
RECORD.
— For safety reasons in severe accidents, the
alternator and starter are separated from


203

Airbag system


the vehicle battery with a pyrotechnic circuit
interrupter.
— Work on the pyrotechnic circuit interrupter
must only be performed by a qualified
technicians who have the experience, in-
formation and special tools necessary to
perform the work safely.
— If the vehicle or the circuit interrupter is
scrapped, all applicable safety precautions

must be followed.
Other things that can affect Advanced
Airbag performance
Changing the vehicle's suspension system can
change the way that the Advanced Airbag System
performs ina crash. For example, using tire-rim
combinations not approved by Audi, lowering the
vehicle, changing the stiffness of the suspension,
including the springs, suspension struts, shock
absorbers etc. can change the forces that are
measured by the airbag sensors and sent to the
electronic control unit. Some suspension changes
can, for example, increase the force levels meas-
ured by the sensors and make the airbag system
deploy in crashes in which it would not deploy if
the changes had not been made. Other kinds of
changes may reduce the force levels measured by
the sensors and prevent the airbag from deploy-
ing when it should.

Z\ WARNING
Changing the vehicle's suspension including
use of unapproved tire-rim combinations can
change Advanced Airbag performance and in-
crease the risk of serious personal injury ina
crash.
— Never install suspension components that
do not have the same performance charac-
teristics as the components originally instal-
led on your vehicle.
— Never use tire-rim combinations that have
not been approved by Audi.

204

Knee airbags
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The knee airbag system can provide supplemen-
tal protection to properly restrained front seat
occupants.
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Fig. 159 Driver's knee airbag
The driver knee airbag is in the instrument panel
underneath the steering wheel > fig. 159, the
airbag for the passenger is at about the same
height in the instrument panel underneath the
glove compartment.
The knee airbag offers additional protection to
the driver's and passenger's knees and upper and
lower thigh areas and supplements the protec-
tion provided by the safety belts.
If the front airbags deploy, the knee airbags also
deploy in frontal collisions when the deployment
threshold stored in the control unit is met
= page 198, More important things to know
about front airbags.
In addition to their normal safety function, safe-
ty belts help keep the driver or front passenger in
position in a frontal collision so that the airbags
can provide supplemental protection.
The airbag system is not a substitute for your
safety belt. Rather, it is part of the overall occu-
pant restraint system in your vehicle. Always re-
member that the airbag system can only help to
protect you if you are wearing your safety belt
and wearing it properly. This is why you should al-
ways wear your safety belt, not just because the
law requires you to do so > page 182, General
notes.

Airbag system

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airbag system
Airbags are only supplemental restraints. Always
wear safety belts correctly and ride in a proper
seating position.
There is a lot that you and your passenger must
know and do to help the safety belts and airbags
to provide supplemental protection.

ZA WARNING
An inflating knee airbag can cause serious in-
jury. Wearing safety belts incorrectly and im-
proper seating positions increase the risk of
serious personal injury and death whenever a
vehicle is being used.
— The knee airbag system cannot protect you
properly if you are seated too close to any of
the airbag locations. When adjusting their
seat positions, it is important that both the
driver and the front passenger keep their
upper bodies and knees at the following
minimum safe distances:
—at least 10 in (25 cm) between the chest
and
the steering wheel/instrument panel.
—at least 4 in (10 cm) between the knees
and the lower part of the instrument pan-
el.
— The risk of personal injury increases if you
lean forward or to the side, or if the seat is
improperly positioned and you are not wear-
ing your safety belt. The risk increases even
more should the airbag deploy.
— Always make sure that the knee airbag can
inflate without interference. Objects be-
tween you and the airbag can increase the
risk of injury in an accident by interfering
with the way the airbag deploys or by being
pushed into you as the airbag deploys.
— Never let anybody, especially children or
animals ride in the footwell in front of the
passenger seat. If the airbag deploys, this
can result in serious or fatal injuries.
— Never carry objects of any kind in the foot-
well area in front of the driver's or pas-
senger's seat. Bulky objects (shopping
bags, for example) can interfere with or
prevent proper deployment of the airbag.

206

Small objects can be thrown through the
vehicle if the airbag deploys and injure you
or your passenger.
— Make sure there are no cracks, deep scratch-
es or other damage in the area of the instru-
ment panel where the knee airbags are lo-
cated.
— If children are incorrectly seated, their risk
of injury increases in a collision > page 210,
Child safety.

Side airbags
Description of side airbags
The airbag system can provide supplemental
protection to properly restrained occupants.

The side airbags are located in the sides of the
front seat backrests > fig. 161 facing the doors.
They are identified by the word “AIRBAG”.
The side airbags installed for the front seating
positions have been designed and certified to
help reduce the risk of injury that can be caused
by airbags when they inflate, particularly when
the occupant sitting next to it is not seated prop-
erly. The side airbag for the front passenger seat
can be used with properly installed child re-
straints. Please be sure to read the important in-
formation and warnings whenever using a child
restraint in a vehicle: Safety belts > page 182,
Airbag system > page 189, Child safety
=> page 210.
The side airbag system basically consists of:
— the electronic control module and external side
impact sensors

Child safety

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Your vehicle is equipped with a front “Advanced
Airbag System” in compliance with United States
Federal Motor Vehicle Safety Standard (FMVSS)
208, as well as Canada Motor Vehicle Safety
Standard (CMVSS) 208 as applicable at the time
your vehicle was manufactured.
The Advanced Airbag system in your vehicle has
been certified to meet the “low-risk” require-
ments for 3- and 6-year old children on the pas-
senger side and small adults on the driver side.
The low risk deployment criteria are intended to
reduce the risk of injury through interaction with
the airbag that can occur, for example, by being
too close to the steering wheel and instrument
panel when the airbag inflates. In addition, the
system has been certified to comply with the
“suppression” requirements of the Safety Stand-
ard, to turn off the front airbag for infants up to
12 months who are restrained on the front pas-
senger seat in child restraints that are listed in
the Standard.
Even though your vehicle is equipped with an Ad-
vanced Airbag system, a child should always ride
in the seat properly restrained for its age and
size. The airbag on the passenger side makes the
front seat a potentially dangerous place for a
child to ride. The front seat is not the safest place
for a child in a forward-facing child safety seat. It
can be a very dangerous place for an infant or a
larger child in a rearward-facing seat.
The vehicle's Advanced Airbag System has a ca-
Pacitive passenger detection system in the front
passenger seat cushion that can detect the pres-
ence of a baby or a child ina child restraint sys-
tem on this seat.
The capacitive passenger detection system regis-
ters the changes that result in an electrical field
when a child, a child restraint, and a baby blanket
are on the front passenger seat. The change in
the measured capacitance due to the presence of
a child, a child restraint, and a baby blanket on
the front passenger seat is related to the child re-
straint system resting on the seat. The measured
capacitance of a child restraint system varies de-
212
pending on the type of system and specific make
and model.
The electrical capacitance of the various types,
makes, and models of child restraints specified
by the U.S. National Highway Traffic Safety Ad-
ministration (NHTSA) in the relevant safety
standard are stored in the Advanced Airbag Sys-
tem control unit together with the capacitances
typical of infants and a 1-year old child. When a
child restraint is used on the front passenger seat
with a typical 1 year-old infant, the Advanced Air-
bag System compares the capacitance measured
by the capacitive passenger detection system
with the data stored in the electronic control
unit.
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system
Regardless of the child restraint that you use,
make sure that it has been certified to meet Safe-
ty Standards and has been certified by its manu-
facturer for use with an airbag. If in exceptional
circumstances you must use it on the front pas-
senger seat, carefully read all of the information
on child safety and Advanced Airbags and heed
all of the applicable WARNINGS. Make certain
that the child and child restraint are correctly rec-
ognized by the capacitive passenger detection
system in the front passenger seat, that the front
passenger airbag is turned off, and that the air-
bag status is always correctly signaled by the
PASSENGER AIR BAG OFF #; light.
Many types and models of child restraints have
been available over the years, new models are in-
troduced regularly incorporating new and im-
proved designs and older models are taken out of
production. Child restraints are not standardized.
Child restraints of the same type typically have
different
weights and sizes and different “foot-
prints”, the size and shape of the bottom of the
child restraint that sits on the seat, when they
are installed on a vehicle seat. These differences
make it virtually impossible to certify compliance
with the requirements for advanced airbags with
each and every child restraint that has ever been
sold in the past or will be sold over the course of
the useful life of your vehicle.

Wheels

Wheels Wheels
and Tires
General information
> Check your tires regularly for
damage, such as punctures,
cuts, cracks, and bulges. Remove
foreign objects from the tire
tread.
>If driving over curbs or similar
obstacles, drive slowly and ap-
proach the curb at an angle.
> Have faulty tires or rims re-
placed immediately.
>Protect your tires from oil,
grease, and fuel.
>Mark tires before removing
them so that the same running
direction can be maintained if
they are reinstalled.
>Lay tires flat when storing and
store them ina cool, dry location
with as little exposure to light as
possible.

J WARNING
—Never drive faster than the
maximum permitted speed for
your tires. This could cause the
tires to heat up too much. This
increases the risk of an acci-
dent because it can cause the
tire to burst.

240


—Always adapt your driving to
the road and traffic condi-
tions. Drive carefully and re-
duce your speed on icy or slip-
pery roads. Even winter tires
can lose traction on black ice.

() Note
—Please note that summer and
winter tires are designed for
the conditions that are typical
in those seasons. Audi recom-
mends using winter tires dur-
ing the winter months. Low
temperatures significantly de-
crease the elasticity of summ-
er tires, which affects traction
and braking ability. If summer
tires are used in very cold tem-
peratures, cracks can form on
the tread bars, resulting in
permanent tire damage that
can cause loud driving noise
and unbalanced tires.
—Burnished, polished or
chromed rims must not be
used in winter driving condi-
tions. The surface of the rims
does not have sufficient corro-
sion protection for this and
could be permanently dam-
aged by road salt or similar
substances.

8S58012721BA
Wheels

Tire designations

B8K-2316


Fig. 181 Tire designation on the side-
wall
@ Tires for passenger vehicles
(if applicable)
“P” indicates a tire for a passen-
ger vehicle. “T” indicates a tire
designated for temporary use.
@ Nominal width
Nominal width of the tire be-
tween the sidewalls in millime-
ters. In general: the larger the
number, the wider the tire.
@) Aspect ratio
Height/width ratio expressed as a
percentage.
@ Tire construction
“R” indicates a radial tire.
©) Rim diameter
Size of the rim diameter in inches.
© Load index and speed rating
The load index indicates the tire's
load-carrying capacity.
The speed rating indicates the
maximum permitted speed. Also
see > A in General information on
page 240.
“EXTRA LOAD”, “xl” or “RF” indi-
cates that the tire is reinforced or
is an Extra Load tire.






Speed rat- /Maximum permitted speed
ing
P up to 93 mph (150 km/h)
Q up to 99 mph (160 km/h)
R up to 106 mph (170 km/h)
S up to 110 mph (180 km/h)
T up to 118 mph (190 km/h)
U up to 124 mph (200 km/h)
H up to 130 mph (210 km/h)
Vv up to 149 mph (240 km/h)?
Zz above 149 mph (240 km/h)?
w up to 168 mph (270 km/h)?
Y up to 186 mph (300 km/h)®)

) For tires above 149 mph (240 km/h),
tire manufacturers sometimes use the
code “ZR”.
241

Wheels

@ US DOT number (TIN) and
manufacture date
The manufacture date is listed on
the tire sidewall (it may only ap-
pear on the inner side of the tire):
DOT... 2218...
means, for example, that the tire
was produced in the 22nd week of
the year 2018.
@) Audi Original Tires
Audi Original equipment tires
with the designation “AO” have
been specially matched to your
Audi. When used correctly, these
tires meet the highest standards
for safety and handling. An au-
thorized Audi dealer or author-
ized Audi Service Facility will be
able to provide you with more in-
formation.
@) Mud and snow capability
“M/S” or “M+S” indicates the tire
has properties making it suitable
to drive in mud or snow. /& indi-
cates a winter tire.
Composition of the tire cord
and materials
The number of plies indicates the
number of rubberized fabric lay-
ers in the tire. In general: the
more layers, the more weight a
242
tire can carry. Tire manufacturers
must also specify the materials
used in the tire. These include
steel, nylon, polyester and other
materials.
@ Maximum permitted load
This number indicates the maxi-
mum load in kilograms and
pounds that the tire can carry.
@ Uniform tire quality grade
standards for treadwear,
traction and temperature
resistance
Treadwear, traction and tempera-
ture ranges > page 255.
@ Running direction
@ Maximum permitted
inflation pressure
This number indicates the maxi-
mum pressure to which a tire can
be inflated under normal operat-
ing conditions.
Glossary of tire and loading
terminology
Accessory weight
means the combined weight (in
excess of those standard items
which may be replaced) of auto-
matic transmission, power steer-
ing, power brakes, power

8S8012721BA
Wheels

windows, power seats, radio, and
heater, to the extent that these
items are available as factory-in-
stalled equipment (whether in-
stalled or not).
Aspect ratio
means the ratio of the height to
the width of the tire in percent.
Numbers of 55 or lower indicate a
low sidewall for improved steer-
ing response and better overall
handling on dry pavement.
Bead
means the part of the tire that is
made of steel wires, wrapped or
reinforced by ply cords and that is
shaped to fit the rim.
Bead separation
means a breakdown of the bond
between components in the bead.
Cord
means the strands forming the
plies in the tire.
Cold tire inflation pressure
means the tire pressure recom-
mended by the vehicle manufac-
turer for a tire of a designated
size that has not been driven for
more than a couple of miles (kilo-
meters) at low speeds in the three
hour period before the tire pres-
sure is measured or adjusted.
Curb weight
means the weight of a motor ve-
hicle with standard equipment in-
cluding the maximum capacity of
fuel, oil, and coolant, air condi-
tioning and additional weight of
optional equipment.
Extra load tire
means a tire designed to operate
at higher loads and at higher in-
flation pressures than the corre-
sponding standard tire. Extra load
tires may be identified as “XL”,
“xl”, “EXTRA LOAD”, or “RF” on
the sidewall.
Gross Axle Weight Rating
(“GAWR”)
means the load-carrying capacity
of a single axle system, measured
at the tire-ground interfaces.
Gross Vehicle Weight Rating
(“GVWR”)
means the maximum total loaded
weight of the vehicle.
Groove
means the space between two ad-
jacent tread ribs.
243
>

Wheels

Load rating (code)
means the maximum load that a
tire is rated to carry for a given in-
flation pressure. You may not find
this information on all tires be-
cause it is not required by law.
Maximum load rating
means the load rating for a tire at
the maximum permissible infla-
tion pressure for that tire.
Maximum loaded vehicle
weight
means the sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight, and
(d) Production options weight
Maximum (permissible)
inflation pressure
means the maximum cold infla-
tion pressure to which a tire may
be inflated. Also called “maxi-
mum inflation pressure.”
Normal occupant weight
means 150 lbs (68 kg) times the
number of occupants seated in
the vehicle up to the total seating
capacity of your vehicle.
244
Occupant distribution
means distribution of occupants
in a vehicle.
Outer diameter
means the overall diameter of an
inflated new tire.
Overall width
means the linear distance be-
tween the exteriors of the side-
walls of an inflated tire, including
elevations due to labeling, deco-
rations, or protective bands or
ribs.
Ply
means a layer of rubber-coated
parallel cords.
Production options weight
means the combined weight of
those installed regular production
options weighing over 5 lbs
(2.3 kg) in excess of those stand-
ard items which they replace, not
previously considered in curb
weight or accessory weight, in-
cluding heavy duty brakes, ride
levelers, roof rack, heavy duty
battery, and special trim.
Radial ply tire
means a pneumatic tire in which
the ply cords that extend to the >

8S8012721BA
Wheels

beads are laid at substantially
90 degrees to the centerline of
the tread.
Recommended inflation
pressure
see > page 243, Cold tire infla-
tion pressure.
Reinforced tire
means a tire designed to operate
at higher loads and at higher in-
flation pressures than the corre-
sponding standard tire. Rein-
forced tires may be identified as
“XL”, “xl”, “EXTRA LOAD”, or “RF”
on the sidewall.
Rim
means a metal support for a tire
or a tire and tube assembly upon
which the tire beads are seated.
Rim diameter
means nominal diameter of the
bead seat. If you change your
wheel size, you will have to pur-
chase new tires to match the new
rim diameter.
Rim size designation
means rim diameter and width.
Rim width
means nominal distance between
rim flanges.
Sidewall
means that portion of a tire be-
tween the tread and bead.
Speed rating (letter code)
means the speed at which a tire is
designed to be driven for extend-
ed periods of time. The ratings
range from 93 mph (150 km/h)
to 186 mph (298 km/h) > table
on page 241. You may not find
this information on all tires be-
cause it is not required by law.
The speed rating letter code,
where applicable, is molded on
the tire sidewall and indicates the
maximum permissible road
speeds. See also > A in General
information on page 240.
Tire pressure monitoring
system*
means a system that detects
when one or more of a vehicle's
tires are underinflated and illumi-
nates a low tire pressure warning
telltale.
Tread
means that portion of a tire that
comes into contact with the road. >
245