2021 AUDI Q8 ECU

4M8012721BF
Driving

— The vehicle battery will gradually drain if
the vehicle is not driven for long periods of
time, or if electrical equipment is used
when the engine is not running. To ensure
that the vehicle can still be started, the
electrical equipment will be limited or
switched off.
IC Te lt
B Drive system: malfunction! Safely stop vehi-
cle
There is a malfunction in the drive system. The
brake booster and the power steering may stop
working. Stop the vehicle immediately or as soon
as possible and do not continue driving. Secure
the vehicle against rolling before exiting the vehi-
cle > page 96. Have the problem corrected by an
authorized Audi dealer or authorized Audi Service
Facility.
B Drive system: malfunction! Please contact
Service
There is a malfunction in the drive system. Drive
slowly to an authorized Audi dealer or authorized
Audi Service Facility to have the malfunction cor-
rected.
Start/Stop system
Applies to: vehicles with Start/Stop system
The Start/Stop system can help increase fuel
economy and reduce CO2 emissions.
In Start/Stop mode, the engine shuts off auto-
matically when stopped, for example at a traffic
light. If certain conditions are met, the engine
may stop before the vehicle has come to a com-
plete stop. If you press the accelerator pedal
when this happens, the engine will start and driv-
ing power will be transmitted.
The ignition and important assist systems such
as the brake booster will remain available during
the Stop phase. The engine will restart automati-
cally when needed.
The Start/Stop system is automatically activated
once
the ignition is switched on.
Switching the Start/Stop system off and on
The & button is located above the selector lever
in the center console. The LED in the button turns
on when the function is switched off.
> Press & to switch the system on or off.
If you switch the system off during a Stop phase,
the engine will start again automatically.
Basic requirements
— The driver's door and hood must be closed.
—"P","N", or "D" must be engaged.
— The steering wheel must not be turned far in ei-
ther direction.
— The vehicle must have driven faster than 2 mph
(3 km/h) since the last time it stopped.
— The vehicle is not in trailer mode.
@) Note
Always switch the Start/Stop system off when
driving through water > page 103.
G) Tips
— Depending on the driving situation, the en-
gine may already stop when coasting before
the vehicle has come to a complete stop.
— Ifyou select the "D" position after shifting
into reverse, the vehicle must be driven fast-
er than 6 mph (10 km/h) in order for the
Start/Stop system to become active again.
This makes it possible to maneuver without
stopping the engine.
Stopping and starting the engine
Applies to: vehicles with Start/Stop system
> Press and hold the brake pedal until the vehicle
has stopped. The @) indicator light appears in
the instrument cluster once the engine stops
automatically.
> The engine starts again when you remove your
foot from the brake pedal. The indicator light
turns off.
If the parking brake is set, the engine will only
start again when the accelerator pedal is pressed. >
103

Driving

Ga / @ Brake pads: wear limit reached. You
can continue driving. Please contact Service
The brake pads are worn. Drive to an authorized
Audi dealer or authorized Audi Service Facility as
soon as possible to have the malfunction correct-
ed.
Brake booster: limited functionality. You can
continue driving. Please contact Service
There is a brake booster malfunction. The brake
booster is available, but its effectiveness is re-
duced. The braking performance may be different
compared to the usual performance. Drive to an
authorized Audi dealer or authorized Audi Service
Facility immediately to have the malfunction cor-
rected.
Brake booster: deactivated. See owner's manual
The brake booster remains active for a brief peri-
od of time after switching off the ignition. Secure
the vehicle against rolling > page 96.
Other indicator lights
When you switch the ignition on, the EG / @
indicator light turns on briefly to check the func-
tion. If the indicator light does not turn on, there
is a system malfunction.
1f EG / @ stays on, there is a malfunction in
the brake system.
©) - A high load was placed on the brakes from
driving downhill for a long period of time. Follow
the instructions in the message to utilize the en-
gine braking effect and to relieve the brakes.
Electromechanical
parking brake
Operating the parking brake
The electromechanical parking brake is used to
secure the vehicle from rolling away unintention-
ally.
The @) switch is located under the selector lever
in the center console. It turns on when the park-
ing brake is set. You can release the parking brake
manually or automatically when you start to
drive.
Setting and releasing the parking brake
> Setting: pull the ©) switch.
> 1f i ii ® appears, the parking brake is hold-
ing the vehicle. You can remove your foot from
the brake pedal.
> Releasing: when the ignition is switched on,
press and hold the brake pedal and press the
button.
If the red indicator light flashes, the braking
force has not built up enough or it has decreased.
You can also secure the vehicle by selecting the
“P” gear or pressing the brake pedal. Make sure
the indicator light is off before you start driving.
Automatically releasing the parking brake
when starting to drive
Requirement: the driver's door must be closed
and the driver’s safety belt must be fastened.
> Press the accelerator pedal to start to drive.

ZX WARNING
If a malfunction occurs in the ABS, ESC, and
braking distribution, interventions that stabi-
lize the vehicle will no longer be available.
This could cause the vehicle to swerve, which
increases the risk that the vehicle will slide.
Do not continue driving. See an authorized
Audi dealer or authorized Audi Service Facility
for assistance.

106
ZA WARNING
—To reduce the risk of an accident, always
make sure the vehicle is situated safely
while stationary.
— If the parking brake is set, it can release au-
tomatically when the accelerator pedal is
pressed. To reduce the risk of an accident,
do not inadvertently press the accelerator
pedal and always shift into “P” when the ve-
hicle is stopped.
— If the power supply fails, you cannot set the
parking brake once it is released, or release
it if it is set. Secure the vehicle against >

4M8012721BF
Driving


rolling before exiting the vehicle > page 96.
See an authorized Audi dealer or authorized
Audi Service Facility for assistance.

G) Tips
— On steep inclines, especially when in trailer
mode, the vehicle may roll backwards unin-
tentionally when starting to drive. To reduce
the risk of this happening, pull and hold the
switch while pressing the accelerator
pedal. If enough drive power has built up at
the wheels and the vehicle does not roll
backwards, then release the switch to start
to drive.
— If you leave the vehicle when “D” or “R” are
engaged, the parking brake will be set auto-
matically.
— Noises when the parking brake is set and re-
leased are normal and are not a cause for
concern.
— The parking brake goes through a self-test
cycle at regular intervals when the vehicle is
stopped. Any noises associated with this are
normal.
Emergency braking function
Emergency braking should only be used in an
emergency, if the standard brake pedal is mal-
functioning or obstructed. When the emergency
braking function is activated, the braking effect is
similar to a heavy braking maneuver.
> Pull and hold the ©) switch while driving.
> An audio warning signal will sound and emer-
gency braking will begin.
> If you press the accelerator pedal, emergency
braking will be canceled.

ZA WARNING
Heavy braking while driving through curves or
in poor road or weather conditions can cause
the vehicle to slide or the rear of the vehicle to
swerve, which increases the risk of an acci-

dent.

Messages
ii) B) Parking brake: malfunction! Safely
stop vehicle. See owner's manual
GG / © Parking brake: malfunction! Please
release parking brake
If one of the two messages appears, there is a
malfunction in the parking brake. If the message
appears while stationary, check if the parking
brake is released and can be reset. If this is the
case,
switch the ignition off and back on.
If the message stays on, if the parking brake can-
not be released, or if the message appears while
driving, do not continue driving. Secure the vehi-
cle against rolling before exiting the vehicle
= page 96. See an authorized Audi dealer or au-
thorized Audi Service Facility for assistance.
ww Parking brake: malfunction! Please contact
Service
There is a malfunction in the parking brake. Drive
to an authorized Audi dealer or authorized Audi
Service Facility immediately to have the malfunc-
tion corrected. Do not park the vehicle on inclines
and shift to “P”.
x | / Parking brake: warning! Vehicle parked
too steep
The braking force may not be enough to secure
the vehicle from rolling away. Park the vehicle in
a place with less of an incline.
& / {Q) Parking brake: applied
The parking brake is set. Press and hold the brake
pedal to release the parking brake.
Special driving situations
Sporty driving
Applies to: RS models
When driving in a sporty style, the wear on all ve-
hicle components is greatly increased, especially
on the engine, transmission, tires, brakes, and
suspension. This can result in increased wear. Al-
so note the following points:
107
>

Driving dynamic

Depending on the setting, the drive power at the
rear axle will be distributed with the sport differ-
ential* to be more sporty or moderate
=>page 115.
In RS models, the sport differential is adjusted
using a separate menu item.
Steering
The power steering will adapt. Light steering is
suitable for long trips on highways or smooth
driving around curves, for example.
Suspension
The suspension adjusts to be tighter or more
comfort-oriented when it comes to compensat-
ing for uneven spots on the road.
Based on the selected setting, the air suspen-
sion* will adjust the ground clearance and the ac-
tive roll stabilization* will provide various de-
grees of compensation for vehicle movements.
Engine sound
The engine sound adapts and can be subtle to
sporty. In the automatic setting, the engine
sound depends on the selected driving program.
quattro with sport differential
Applies to: RS models
Depending on the setting, the drive power at the
rear axle will be distributed with the sport differ-
ential* to be more sporty or moderate
=>page 115.
ESC
Applies to: RS models
The ESC sport mode can be activated. Also refer
to the important information regarding driving
with ESC limited > page 116.
Suspension
CET aN mer) t cd
Applies to: vehicles with suspension control
The adaptive dampers are an electronically-con-
trolled damping system. The firmness of the sus-
pension will adapt to the driving conditions and
the driving situation. The settings depend on the
selected Audi drive select* mode.
112
Air suspension
Applies to: vehicles with air suspension
The air suspension is an electronically-controlled
suspension and leveling system. The firmness of
the suspension will adapt to the driving condi-
tions and the driving situation. The system balan-
ces out changes in load. The vehicle level will also
adapt gradually to the vehicle speed in order to
reduce the wind resistance at high speeds and in-
crease the ground clearance at low speeds. The
settings depend on the selected Audi drive se-
lect* mode.
Displaying the vehicle level
> Applies to MMI: Select on the home screen: VE-
HICLE > Audi drive select.
The filled-in boxes represent the current vehicle
level. The more boxes that are filled in, the high-
er the ground clearance. The box that corre-
sponds with the current vehicle level will flash
while the vehicle is lifting or lowering. The target
level is highlighted in color.
Raising the vehicle
> Applies to MMI: Select on the home screen: VE-
HICLE > Audi drive select.
> Press Raise to reach the highest vehicle level
and thus the maximum ground clearance.
> Press Lower to lower the vehicle down again.
The Audi drive select* mode will be changed if
necessary when the vehicle is raised.
The vehicle will lower at speeds of approximately
20 mph (30 km/h) and below. This function may
only be used temporarily when increased ground
clearance is necessary. It is not intended for long
drives.
@) Note
— Also refer to the information about ground
clearance > page 113.
— When transporting the vehicle on a road
carrier, rail carrier, ship carrier, or other car-
rier, it may only be secured at the running
surfaces of the tires (circumference). Secur-
ing the vehicle at the axle components, sus-
pension struts, or towing eyes is not

4M8012721BF
Driving dynamic

permitted because the pressure in the air
suspension struts can change during trans-
port. The vehicle might not be secured suffi-
ciently if this happens.
Active roll stabilization
Applies to: vehicles with active roll stabilization
The active roll stabilization enhances the air sus-
pension with an electromechanically-controlled
suspension system. It influences targeted rolling
movements when driving on curves and during
fast swerving maneuvers. The settings depend on
the selected Audi drive select* mode.
Ground clearance
The vehicle height and clearance can be influ-
enced by the following factors:
— Change in temperature
— Change in load
— Change to the Audi drive select* mode
— Lifting and lowering via the air suspension*
— Lower the rear* of the vehicle

ZA WARNING
To reduce the risk of injury, make sure no one
gets pinched when the vehicle level is chang-
ing, for example when cleaning the under-
body or the wheel housings.
@) Note
Always make sure there is enough clearance
above and below the vehicle. This is especially
important for entrances with height restric-
tions, for example, before driving into under-
ground garages. You could also scrape the
ground when driving over the edges of curbs
or on steep ramps, which could damage your
vehicle.
Messages
Bair suspension: malfunction! You may con-
tinue driving slowly at max. XX mph (km/h)

There is a malfunction. Driving stability may be
limited. Drive to an authorized Audi dealer or au-
thorized Audi Service Facility immediately. Do not
drive faster than the speed given in the message.
B Air suspension: malfunction! You can contin-
ue driving. Speed limited to max. XXX
There is a malfunction. Driving stability may be
limited. Drive to an authorized Audi dealer or au-
thorized Audi Service Facility immediately. The
maximum speed has been limited.
B Air suspension: malfunction! Safely stop ve-
hicle. Steering and ground clearance limited
There is a malfunction. Do not continue driving.
Secure the vehicle against rolling before exiting
the vehicle > page 96. Avoid turning the steering
wheel, because the vehicle ground clearance may
be so low that turning the steering wheel could
result in damage to the wheels and wheel hous-
ings.
BA Active roll stabilization: malfunction! Limit-
ed stability. See owner's manual
There is a heavy load on the vehicle electrical sys-
tem or the roll stabilization. The roll stabilization
functions have already been switched off tempo-
rarily. Driving stability is reduced. Continue driv-
ing with caution.
If the indicator light does not turn off after a
long period time and after switching the ignition
off and on, drive to an authorized Audi dealer or
authorized Audi Service Facility immediately to
have the malfunction corrected. Otherwise, con-
ditions such as an uneven road surface can lead
to vehicle damage.
6 | Suspension: malfunction! You can continue
driving
There is a malfunction. See an authorized Audi
dealer or authorized Audi Service Facility for as-
sistance.
EB Air suspension: vehicle too low. Limited
ground clearance
The vehicle ground clearance is very low. Wait un-
til the air suspension system has restored normal
ground clearance. Have an authorized Audi dealer >
113

Driving dynamic

or authorized Audi Service Facility repair the mal-
function immediately if the indicator light does
not turn off after a significant period of time.
|<] Air suspension: malfunction! Please contact
Service
There is a malfunction. The driving stability may
be limited and the ground clearance may be low.
See an authorized Audi dealer or authorized Audi
Service Facility for assistance.
Audi drive select: automatic suspension low-
ering. See owner's manual
The vehicle level is adjusted to the setting stored
for the active personal profile > page 32.
Audi drive select: automatic suspension lift.
See owner's manual
The vehicle level is adjusted to the setting stored
for the active personal profile > page 32.
Steering
Electromechanical steering supports the driver's
steering movements by electronically adapting
the power steering depending on the vehicle
speed. The settings depend on the selected Audi
drive select* mode.
Progressive steering
Applies to: vehicles with progressive steering
The driving dynamic and driving stability are in-
creased by the steering ratio based on the steer-
ing wheel angle. The steering is very direct when
the steering wheel angle is sharp, and indirect
when the angle is low. This enables comfortable
maneuvering and a precise steering response at
higher driving speeds.
All-wheel steering
Applies to: vehicles with all-wheel steering
Additional steering ability at the rear axle im-
proves the driving dynamic and stability. At low
speeds, the rear wheels are steered in the oppo-
site direction from the front wheels to reduce the
turning radius. At high speeds, steering the rear
wheels in the same direction as the front wheels
114
improves the vehicle response and driving stabili-
ty.
a Steering: malfunction! Please stop vehicle
The power steering may have failed. Adapt your
driving style immediately to compensate for the
fact that it may be more difficult to turn the
steering wheel, and stop your vehicle in a safe lo-
cation as soon as possible. Do not continue driv-
ing. See an authorized Audi dealer or authorized
Audi Service Facility for assistance.
a Steering: malfunction! Please stop vehicle.
Pay attention to distance at side
The rear axle steering may have failed. More
space on the road may be needed at the side of
the vehicle, and the turning radius may be much
larger. Slow down immediately, and stop your ve-
hicle as soon as possible in a safe location with
enough space at the sides of the vehicle. Do not
continue driving. See an authorized Audi dealer
or authorized Audi Service Facility for assistance.
BS Steering: malfunction! Please stop vehicle
There is a malfunction in the electronic steering
lock. You cannot turn the ignition on. Secure the
vehicle against rolling before exiting the vehicle
= page 96. Do not tow your vehicle because it
cannot be steered. See an authorized Audi dealer
or authorized Audi Service Facility for assistance.
a Steering: malfunction! You can continue
driving
There is a malfunction in the steering system.
Steering may be more difficult or more sensitive.
Adapt your driving style. Have the steering sys-
tem checked immediately by an authorized Audi
dealer or authorized Audi Service Facility. Please
note that the red indicator light may turn on af-
ter restarting the engine. Do not continue driving
if it does.
a Steering: malfunction! Adapt driving style.
Larger turning radius
The rear axle steering may have failed. The vehi-
cle will have a larger turning radius, and the sta-
bility when driving around curves will be

Trailer towing

Trailer towing
Driving with a trailer
er else)
Your vehicle is primarily intended for transport-
ing people and luggage. However, if you drive
with a trailer, follow the technical requirements,
the operation and driving tips, and the legal reg-
ulations.
Driving with a trailer affects the vehicle's energy
usage, performance, and wear. It also requires
higher concentration from the driver.

ZA\ WARNING
Do not transport any people in a trailer due to
the risk of fatal injury.
Technical requirements
Trailer hitch

Only use a trailer hitch with a removable ball
hitch mount and ball hitch. The trailer hitch must
be permitted for the vehicle, the trailer and the
permitted total weight of the trailer being
pulled. Above all, it must be securely and safely
attached to the vehicle trailer.
Never mount a trailer hitch on the bumper. The
trailer hitch must be mounted in a way that does
not impair the function of the bumper. Do not
make any changes to the exhaust system and the
brake system.
Check regularly if the trailer hitch is securely
mounted. Always follow the instructions given by
the trailer hitch manufacturer.
Trailer brakes
If the trailer has its own brake system, then fol-
low the manufacturer specifications. However,
the brake system on the trailer must never be
connected to the vehicle brake system.
Engine cooling system
Driving with a trailer means a higher load on the
engine and the cooling system. The cooling sys-
tem must be designed for additional load and
contain enough coolant > @.
118

ZA\ WARNING
— Never mount a "weight-distributing" or
"load-balancing" trailer coupler as the trailer
hitch. The vehicle was not designed for
these types of trailer hitches. The trailer
hitch can malfunction and the trailer can
break off from the vehicle.
— If the trailer is equipped with electronic
brakes, these brakes cannot be activated by
a factory-installed control system, which in-
creases the risk of an accident.
—To reduce the risk of injury, always remove
the ball hitch mount if no trailer is mount-
ed
@) Note
Longer inclines cannot be driven without a
suitable cooling system, especially if the out-
side temperatures are high. Otherwise, this
increases the risk of engine damage.
ey emia aCe
Towing capacity

The permitted towing capacity must not be ex-
ceeded under any circumstances > page 314.
You can drive up larger inclines if you are not us-
ing the maximum towing capacity.
The specified towing weights only apply at eleva-
tions up to 3,200 feet (1,000 m) above sea level.
As the elevation increases, the engine power de-
creases due to the decreasing air pressure. This
reduces the hill climbing ability and towing ca-
pacity. For every additional 3,200 feet (1,000 m),
the maximum permitted towing weight must be
reduced by approximately 10%. The permitted
towing weight is the combined weight of the
(loaded) vehicle and the (loaded) trailer.
Tongue weight
The maximum permitted tongue weight of the
trailer drawbar on the trailer hitch ball head must
not be exceeded.
For driving safety, Audi recommends always us-
ing
the maximum permitted tongue weight, but
do not exceed this weight. Distributing the cargo >

4M8012721BF
Trailer towing

in the trailer correctly will help to achieve this
weight. Having the tongue weight too low affects
the vehicle's handling.
You can determine the tongue weight using a
tongue weight scale, a bathroom scale, or a pub-
lic weigh station, for example.
The permitted tongue weight of your vehicle can
be found in the vehicle documentation or in
=> page 314.
Load distribution
Poor cargo load and distribution can negatively
impact vehicle handling. Load the trailer based
on the following criteria as much as possible:
— Store objects in the vehicle luggage compart-
ment, if possible. The vehicle should always
carry the heaviest possible load and the trailer
should have the lightest possible load.
— Distribute the load in the trailer so that the
heavy objects are as close to the axle as possi-
ble.
— Secure objects so that they do not slide.
— Utilize the maximum permitted tongue weight
if possible.
Tires
Set the tire pressure on your vehicle for a “full
load”; see the tire pressure sticker > page 266. If
necessary, also adjust the tire pressure on the
trailer according to the manufacturer's specifica-
tions.
The trailer and the vehicle should be equipped
with winter tires when driving in winter tempera-
tures.
Outside mirrors
If you cannot see the traffic behind the trailer
with the standard exterior mirrors, then you
must attach additional exterior mirrors. Adjust
them so you have a sufficient visibility behind
you.
Exterior lighting
Follow the legal regulations for lighting on your
trailer that are applicable in the country where
you are operating the vehicle. Contact an author-
ized Audi dealer or authorized Audi Service Facili-
ty for more information.
Before you start driving, check all lighting equip-
ment on the trailer while it is hitched to the vehi-
cle.
The headlight range control automatically ad-
justs the light range of the headlights.
Safety chains
Make sure the safety chains are correctly applied
when pulling a trailer. The chains should hang
enough so that the trailer can drive around
curves. However, they must not touch the
ground.
Air suspension
Applies to: vehicles with air suspension
The Audi drive select* comfort mode > page 111
must be selected before you adjust the tongue
weight on the trailer and hitch the trailer >,
> page 113.
The air suspension trailer mode must be switched
on.
Applies to MMI: select on the home screen: VE-
HICLE > Settings & Service > Air suspension:
trailer.
Switch trailer mode off again when you are no
longer towing a trailer.
For vehicles with a factory-installed trailer hitch,
the air suspension trailer mode will automatically
switch on if you connect the trailer connector to
the socket.
When using rear carrier systems that are mount-
ed directly on the trailer hitch ball head, you can
also switch trailer mode off manually.
If you must drive on roads that are in poor condi-
tion, you can raise the vehicle again after hitching
the trailer or after adjusting the tongue weight
> page 113.
You can also increase ground clearance by select-
ing the Audi drive select* offroad or allroad
modes > page 111.
119