2009 AUDI A4 CABRIOLET sensor

On the road ------------------------------.J
Keep the sensors in the rear bumper clean and free from ice so that
the acoustic park assist system can function properly.
& WARNING
• Sensors have dead spaces in which objects cannot be
detected . Be especially alert for small children and animals, since
they are not always detected by the sensors.
• The acoustic park assist system is not a substitute for the
driver's own caution and alertness. Ultimate responsibility always
remains with the driver during parking and similar maneuvers .
Always watch where you are driving.
0 Note
• Remember that low obstacles for which a warning has already
been issued may "dive" below the system's sensing zone if the
vehicle is being backed up closer. In this case, the warning sound
shutting off does
not indicate that you have cleared the obstacle .
Instead, impact is imminent.
• Objects such as trailer hitches, barrier chains, narrow posts or
fences covered by a thin layer of paint may not always be detected
by the system . They can still damage your vehicle without a
warning.
[ i] Tips
Keep the sensors in the rear bumper clean and free of snow and ice
so that the acoustic parking assist system can function properly. •
Controls and equip ­
ment
Cruise control
General information
The cruise control system allows you to maintain a
constant speed.
The cruise control system allows you to maintain a constant driving
speed when driving faster than 18 mph (30 km/h) -to the extent this
is possible with the given engine power and braking characteristics .
This allows you to take your foot off the "gas" and rest it, especially
on long trips.
The indicator light (U.S. models :
CRUISE , Canadian models:•(') ) in the
instrument cluster illuminates when the system is on.
& WARNING
• To help keep the vehicle under control, do not use the cruise
control system when driving on winding or slippery roads (as
caused by heavy rain or loose gravel on the road surface), or in
heavy or varying traffic.
• Only use the cruise control when traffic, road and weather
conditions allow you to drive at a steady speed.
[ i] Tips
The cruise control cannot maintain a constant speed when driving
downhill. The vehicle will accelerate under its own weight. Down­
shift to a lower gear or use the brakes to slow down .•

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Automatic rollover protection system
Function
The automatic roll over protection system helps to protect
the passengers in case the vehicle turns over.
1J ~
I ...
,
... . ' : :
: :
'
F ig . 157 Rear sea ts:
ex te n sio n area o f ro ll­
over ba rs
F ig . 158 Rea r sea ts :
r ollo ver bars up and
full y dep loyed
The automatic rollover protection system cons ists of these compo ­
nents:
• two solid rollover bars
• the safety bel ts with belt tensioners
• the windshield frame
• the ro llover sensor system. The automatic rol
lover protection system provides additional
protection in case the vehicle ro lls over. As the vehicle starts to tilt,
the sensors activate the two rollover bars located behind the rear
seats to shoot up wi thin a fraction of a second~ fig. 158 .
In combinat ion with the reinforced windshield frame and the bel t
tensioners, the rollover p rotection bars help to protect the passen ­
gers in the front and in the rear in case of a rollover.
The automatic rollover protection system activates with the power
top open
and closed.
& WARNING
Do not place any obje cts in the ar ea be hind the r ear seats
~ fig . 157. T his is the e xact area where the rollover b ars will shoot
up wh en th e syst e m i s triggered . An y ob jects si tting in th is s pac e
w ill be cata p ulte d into the inter ior. Depending on the ir wei ght,
object s pl ace d there can also s lo w do wn rap id deploym ent of th e
r o llover bars. -Ri sk of seri ou s inj ur y or deat h! •
When is the rollover protection system
triggered?
T he rollover protection system is triggered in a collisi on or
if the vehicle overturns in an accident.
The electronic control unit processes the signals from the on -board
sensors, evaluates vehicle motion and forces act ing on the vehic le.
Depending on the severity of the co llision, the control unit then acti ­
vates the rol lover protection system .
If the vehicle rol ls sideways beyond a certain angle , the first action
is to extend the ro llover bars . If the vehicle rolls further, the system
wil l additional ly activate the front belt tensioners and, if there are
passengers on the rear seats and they are wearing the safety belts,
the rear belt tensioners as well. ..,

___ S_a_ f_ e_ t..: y_ b_e_ l_ t _s _______________________________________________ _
Improperly worn safety belts
Incorrectly positioned safety belts can cause severe inju­
nes.
Wearing safety belts improperly can cause serious injury or
death. Safety belts can only work when they are correctly positioned on the body. Improper seating positions reduce
the effectiveness of safety belts and will even increase the
risk of injury and death by moving the safety belt to critical
areas of the body. Improper seating positions also increase
the risk of serious injury and death when an airbag deploys
and strikes an occupant who is not in the correct seating
position . A driver is responsible for the safety of all vehicle
occupants and especially for children. Therefore:
- Never permit anyone to assume an incorrect sitting posi­
tion in the vehicle while traveling=>&.
& WARNING
Improperly worn safety belts increase the risk of serious personal
injury and death whenever a vehicle is being used.
• Always make sure that all vehicle occupants are correctly
restrained and stay in a correct seating position whenever the
vehicle is being used.
• Always read and heed all WARNINGS and other important infor­
mation
=> page 162. •
Safety belt pretensioners
How safety belt pretensioners work
In front, side and rear-end collisions above a particular
severity, safety belts are tensioned automatically.
The safety belts are equipped with safety belt pretensioners . The
system is activated by sensors in front, side and rear -end collisions
of great severity . This tightens the belt and takes up belt slack=>&.
in "Service and disposal of safety belt pretensioner" on
page 167.
Taking up the slack helps to reduce forward occupant movemen t
during a collision.
[ i] Tips
The safety belt pretensioner can only be activated once.
• In minor frontal and side collisions , in rear-end collisions, in a
rollover and in accidents involving very little impact force, the safety
belt pretension er are not activated.
• When the safety belt pretensioners are activated, a fine dust is
released. This is normal and is not caused by a fire in the vehicle.
• The relevant safety requirements must be observed when the
vehicle or components of the system are scrapped . A qualified deal­
ership is familiar with these regulations and will be pleased to pass
on the information to you.
• Be sure to observe all safety, environmental and other regula ­
tions if the vehicle or individual parts of the system, particularly the
safety belt or airbag, are to be disposed. We recommend you have
your authorized Audi dealer perform this service for you. •

Airbag system -----------------=~-
& WARNING (continued)
• If you must install a rearward facing child safety seat on the
front passenger seat because of exceptional circumstances and
the PASSENGER AIR BAG OFF light does not come on and stay on,
immediately install the rear -facing child safety seat in a rear
seating position and have the airbag system inspected by your
Audi dealer.
_& WARNING
If, in exceptional circumstances, you must install a forward-facing
child restraint on the front passenger's seat:
• Always make sure the forward-facing seat has been designed
and certified by its manufacturer for use on a front seat with a
passenger front and side airbag .
• Never put the forward-facing child restraint up against or very
near the instrument panel.
• Always move the passenger seat into its rearmost position in
the seat's fore and aft adjustment range, as far away from the
airbag as possible, before installing the forward-facing child
restraint. 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. •
Advanced Airbag System components
The front passenger seat in your vehicle has a lot of very important
parts of the Advanced Airbag System in it. These parts include the
weight-sensing mat, sensors, wiring, brackets, and more. The func­
tion of the system in the front passenger seat is checked by the elec­
tronic control unit when the ignition is on. The control unit monitors
the Advanced Airbag System and turns the airbag indicator light on
when a malfunction in the system components is detected. The
function of the airbag indicator light is described in greater detail
Controls and equip­ ment Safety first Vehicle operation
below.
Because the front passenger seat contains important parts
of the Advanced Airbag System, you must take care to prevent it
from being damaged. Damage to the seat may prevent the
Advanced Airbag for the front passenger seat from doing its job in
a crash.
The front Advanced Airbag System consists of the
following:
• Crash sensors in the front of the vehicle that measure vehicle
acceleration/deceleration to provide information to the Advanced
Airbag System about the severity of the crash.
• An electronic control unit, with integrated crash sensors for front
and side impacts. The control unit "decides" whether to fire the
front airbags based on the information received from the crash sensors. The control unit also "decides" whether the safety belt
pretensioners should be activated.
• An Advanced Airbag with gas generator for the driver inside the
steering wheel hub.
• An Advanced Airbag with gas generator inside the instrument
panel for the front passenger .
• A weight-sensing mat under the upholstery padding of the front
passenger seat cushion that measures the total weight on the seat.
The information registered is sent continuously to the electronic
control unit to regulate deployment of the front Advanced Airbag on
the passenger side.
• An airbag monitoring system and indicator light in the instru ­
ment cluster ~
page 179.
• The PASSENGER AIR BAG OFF light comes on and stays on in the
center of the instrument panel~
page 180, fig. 174 and tells you
when the front Advanced Airbag on the passenger side has been
turned off .
• A sensor below the safety belt latch for the front seat passenger
to measure the tension on the safety belt. The tension on the safety
belt and the weight registered by the weight -sensing mat help the
control unit "decide" whether the front airbag for the front _,.
Vehicle care Do-it-yourself service Technical data

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passenger seat shou ld be turned off o r not=> page 1 70, "C hild
r es train ts on the fron t sea t - som e impo rtant thin gs to kno w".
• A sensor in the safety belt latch for the driver and fo r the front
s e at pass enger that s enses w hether tha t sa fety b elt is la tc he d o r no t
and transmits this information to the el ectronic control unit.
& WARNING
Damage to the front passenger seat can prevent the front airbag
from working properly .
• Improper repair or disassembly of the front passenger and
driver seat will prevent the Advanced Airbag System from func ­
tioning properly.
• Repairs to the front passenger seat must be performed by qual­
ified and properly trained workshop personnel.
• Never remove the front passenger or driver seat from the
vehicle.
• Never remove the upholstery from the front passenger seat .
• Never disassemble or remove parts from the seat or disconnect
wires from it .
• Never carry sharp object s in your pockets or place them on the
seat . If the weight-sensing mat in the passenger seat is punctured
it cannot work properly.
• Never carry things on your lap or carry objects on the
passenger seat. Such items can increase the weight registered by
the weight-sens ing mat and send the wrong information to the
airbag control unit .
• Never store items under the front passenger seat. Parts of the
Advanced Airbag System under the passenger seat could be damaged , preventing them and the airbag system from working
properly.
• Never place seat covers or replacement upholstery that have
not been specifically approved by Audi on the front seats.
& WARNING (continued )
• Seat covers can prevent the Advanced Airbag System from
recognizing child restraints or occupants on the front passenger
seat and prevent the side airbag in the seat backrest from
deploying properly .
• Never use cushions, pillows, blankets or similar items on the
front passenger seat . The additional padding will prevent the
weight-sensing mat in the seat from accurately registering the
child restraint or person on the seat and prevent the Advanced
Airbag System from functioning properly.
• If you must use a child restraint on the front passenger seat
and the child restraint manufacturer's instructions require the use
of a towel , foam cushion or something else to properly position
the child restraint , make certain that the PASSENGER AIR BAG OFF
light comes on and stays on whenever the child restraint is
i nstalled on the front passenger seat .
• If the PASSENGER AIR BAG OFF light does not come on and stay
on , immediately install child restraint in a rear seating position
and have the airbag system inspected by your Audi dealer. •
How the Advanced Airbag System
components work together
The front Advanced Airbag System and the si de airba gs supp lement
t h e protection offe red by the front three -point safety be lt s with
pretensioners and load limiters and the adjustab le head restraints
to help reduce the risk of in jury in a wide range of accident and
cras h situati ons . Be sure to read the im por tant in fo rmati on a bout
safety and heed the WARN INGS in this chapter.
De ploy men t of the Advanc ed A ir b ag Syst em and the activa tion of
th e safety belt pretens ioner d epends on the dece leration measured
b y the c ra sh se nsors and reg istered by the elec tronic co ntrol un it .
C rash severity depends on speed and dece leration as well as the
mass an d stiff ness of the vehicle o r obj ect invo lved in the c ra sh.
~

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& WARNING (continued )
airbag dur ing braking or in a sudden maneuver . Objects ne ar the
airbags can become proje ctiles and cau se injury , particularly when
the seat is reclined .
• Never tilt the front passenger seat backrest forward when the
vehicle is moving . An inflating airbag will force the backrest back­
ward and can injure rear seat occupants.
_& WARNING
The fine dust created when airbags deploy can cause breathing problems for people with a history of asthma or other breathing
conditions.
• To reduce the risk of breathing problems, those with asthma or
other respiratory conditions should get fresh air right away by
getting out of the vehicle or opening windows or doors.
• If you are in a collis ion in which airbags deploy, wash your
hands and face with mild soap and water before eating.
• Be careful not to get the dust into your eyes , or into any cuts or
scratches .
• If the residue should get into your eyes, flush them w ith
water. •
Monitoring the Advanced Airbag
System
Airbag monitoring indicator light :~
Two sep arate in dica tors m onitor the fu ncti on of th e
Adv anced A irba g Sys tem: the airbag moni tor ing in dica to r
l ight and t he
PASSENGER AIR BAG OFF light.
The Advanc ed A ir b ag S yst em (includ ing the e lec tronic co ntro l unit,
sensor c ircuits and system wiring) is monitored continuously to
Controls and equip­ ment Safety first Vehicle operation make sure that it is functioning properly whenever the ignition is on
.
Eac h tim e you tu rn on t he ignit io n, th e airbag monitoring ind ica tor
light
fl wi ll come on for a few seconds (self diagnostics) .
The system must be inspected when the indicator l ight ~:
• do es not com e on when the ig nit ion is sw itch ed on,
• does not go out a few seconds after you have switched on the
i gni tion , or
• comes on while driving.
I f an a irbag s ystem malfu ncti on is detec ted , the indi cator light will
first start flash ing to catch the driver's attention and then sta y on
co nti nuou sly to serve as a constant r eminder to h ave the sys tem
inspected immediately.
If a malf unctio n occurs that t urns the front airbag on the passenger
s id e off , the PASS ENGER AIR BAG OFF light w ill come on a nd s ta y on
whenever the ig nition is on.
_& WARNING
An airbag system that is not functioning properly cannot provide
s upplemental protect ion in a frontal crash .
• If the airbag indicator light comes on , it means that there may
be something wrong with the Advanced Airbag System . It is
possible that the airbag will inflate when it is not supposed to, or
will not inflate when it should .
• Have the airbag system inspected immediately by your Audi
dealer. •
Vehicle care Do-it-yourself service Technical data

___ A_ ir_b_ a..::g =-- s__,y:.... s_ t _e_ m ___________________________________________________ _
PASSENGER AIR BAG OFF light
............. Fig. 174 Section from
the instrument panel:
PASSENGER AIR BAG
OFF light
The PASSENGER AIR BAG OFF light is located in the center of the
instrument panel
~ fig. 174.
The
PASSENGER AIR BAG OFF light will come on and stay on to tell
you when the front Advanced Airbag on the passenger side has
been turned off by the electronic control unit . Each time you turn on
the ignition , the
PASSENGER AIR BAG OFF light will flash for a few
seconds and :
• will stay on if the front passenger seat is not occupied,
• will stay on if there is a small child or child restraint on the front
passenger seat,
• will go out if the front passenger seat is occupied by an adult as
registered by the weight -sensing mat .
The
PASSENGER AIR BAG OFF light must come on and stay on if the
ignition is on and
• a car bed has been installed on the front seat, or
• a rearward-facing child restraint has been installed on the front
passenger seat, or
• a forward-facing child restraint has been installed on the front
passenger seat, or
• the weight registered on the front passenger seat is equal to or
less than the combined weight of a typical 1 year-old restrained in one of the rear-facing or forward-facing infant restraints
listed in
Federal Motor Vehicle Safety Standard 208 with which the Advanced
Airbag System in your vehicle was certified .
If the front passenger seat is not occupied, the front airbag will not
deploy, and the
PASSENGER AIR BAG OFF light will stay on. Never
install a rearward -facing child restraint on the front passenger seat,
the safest place for a child in any kind of child restraint is at one of
the seating positions on the rear seat~
page 170, "Child restraints
on the front seat- some important things to know" and~
page 190,
"Child Safety".
If the PASSENGER AIR BAG OFF light comes on when one of the
conditions listed above is met, be sure to check the light regularly
to make certain that the
PASSENGER AIR BAG OFF light stays on
continuously whenever the ignition is on. If the
PASSENGER AIR
BAG OFF
light does not appear and not stay on all the time, stop as
soon as it is safe to do so and
• reactivate the system by turning the ignition off and then turning
it on again;
• remove and reinstall the child restraint. Make sure that the child
restraint is properly installed and that the safety belt for the front
passenger seat has been correctly routed around the child restraint
as described in the child restraint manufacturer's instructions;
• make sure that the convertible locking feature on the safety belt
for the front passenger seat has been activated and that the safety
belt has been pulled tight . The belt must not be loose or have loops
of slack so that the sensor below the safety belt latch on the seat can
do its job
~ page 200.
• make sure that things that may increase the weight of the child
and child safety seat are not being transported on the front
passenger seat;
• make sure that the safety belt tension sensor is not blocked.
Shake the safety belt latch on the front passenger seat back and
forth;
• If a strap or tether is being used to tie the child safety seat to the
front passenger seat, make sure that it is not so tight that it causes _,,

__________________________________________________ A_ i_ r _b _a...; g::- s_ y=--- s_t _e _m ___ lffllll
& WARNING (continued )
• Always make sure that the side airbag can inflate without inter­
ference :
- Never install seat covers or replacement upholstery over the
front seatbacks that have not been specifically approved by
Audi.
- Never use additional seat cushions that cover the areas
where the side airbags inflate.
- 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 be activated only once. After an airbag
has inflated, it must be replaced by an authorized Audi dealer or
qualified technician who has the technical information , training
and special equipment nece ssary.
• The airbag system can be deployed only once . After an airbag
has been deployed , it must be replaced with new replacement
part s designed and approved especially for your Audi model
version. Replacement of complete a irbag systems or airbag
components must be performed by qualified workshops only .
Make sure that any airbag service action is entered in your Audi
Warranty
& Maintenance booklet under AIRBAG REPLACEMENT
RECORD .
• In accidents when an airbag is deployed , the vehicle battery
s eparates the alternator and the starter from the vehicle electrical
system for safety reasons with a pyrotechnic circuit interrupter.
-Work on the pyrotechnic circuit interrupter must only be
performed by a qualified dealer -risk of an accident !
- If the vehi cle or the circuit interrupter is scrapped , all appli ­
cable safety precautions must be followed . •
Controls and equip­ ment Safety first
Vehicle operation
Other things that can affect Advanced Airbag
performance
Changing the vehicle 's suspension system can cha nge the way that
the Advanc ed Ai rbag Syste m perfor ms in a cras h. Fo r ex amp le,
u sing tire -rim combinations not a pproved by Audi, lowering the
ve hicle , c hang ing the st iffness o f the suspe nsion, inclu din g the
spr ings, s uspension struts, shock absorbers etc. can change the
fo rc es that ar e meas ured by th e a irbag sens ors and sent to the e lec ­
tronic control un it. Some suspens ion changes can, for example,
in crea se th e fo rc e leve ls meas ured by th e se nsors and ma ke t he
airbag system dep loy in crash es in wh ich it wou ld not dep loy if the
c h anges had no t been m ade . Ot her k in ds of cha nge s m ay red uce
the fo rce levels measured by the sensors and p revent t he airba g
fr om depl oyin g whe n it should.
T he sensors in the safe ty b elt b uckle fo r the driver a nd front
passenger seat te ll the electronic control module if the safety belt is
l a tc h e d or not. If the s afe ty be lt is bei ng use d, t he fr ont ai rbag w ill
dep loy at a s lightly higher rate of vehic le dece leration than if the
sa fe ty belt is not be ing used . T here for e, in a partic ular co lli sion , it is
possible t hat an airbag will not dep loy at a seating position w here
the safe ty belt is b ein g us ed b ut will infl ate a t th e po siti on w here the
safety belt is not being used. It is important that nothi ng interfere
with the safety belt b uck les so that the sensors can send the correct
i nformat ion about safety b elt use to the electronic control un it.
& WARNING
Changing the vehicle's suspension including use of unapproved
tire -rim combinations can change Advanced Airbag performance
and increase the risk of serious personal injury in a crash.
• Never install suspension components that do not have the
same performance characteristics as the components originally
installed on your vehicle .
• Never use tire-r im combinations that have not been approved
by Audi. .,.
Vehicle care Do-it-yourself service Technical data