2021 AUDI A8 check engine light

4N0012721BF
Quick access

—Park assist plus ............... 198
— Driver assistance systems ...... 153
@_ Depending on equipment:
—Cup holder ..............00.. 95
—SOCkEt: ss seas ¢ 5 cease go eR Fe ee 94
@0) Depending on equipment:
— Starting the engine if there is a


malfunction ................. 108
— Audi music interface .......... 252
—Audi phone box ............... 211
@) Electromechanical parking brake
button 2... 6... cece ee ee eee ee 121
@ Automatic transmission selector
lever... 2... cece eee eee eee ee 109
@ [START ENGINE STOP] button .... 107
@4 Steering wheel adjustment ...... 78
@5) Lever for:
— Cruise control system ......... 163
— Adaptive cruise assist .......... 166
@8 Connection port for the On Board
Diagnostic System (OBD) ........ 333
@) Buttons for:
> LIQHtS sc ss sees ¢ 2 wees 3s ewes G 58
—All-weather lights ............ 58
— Rear fog lights ............... 58
Hood release .............0.00. 276
@9) Button for:
— Luggage compartment lid ...... 48
— Fuel filler door release (plug-in
hybrid drive) ............0.00. 27
60 Exterior mirror adjustment ...... 64
@2 Buttons for:
— Power windows .............. 52
—Child safety lock .............. 51
@) Tips
Some the equipment listed here is only instal-
led in certain models or is available as an op-
tion.
Indicator lights overview
The indicator lights in the instrument cluster
blink or turn on. They indicate functions or mal-
functions. Some warning and indicator lights
turn on when you switch the ignition on and must
turn off when the drive system is switched on or
while driving.
With some indicator lights, messages may ap-
pear and warning signals may sound. The indica-
tor lights and messages may be covered by other
displays. To show them again, select the second
tab for messages with the multifunction steering
wheel & page 13.
Some indicator lights in the display can display in
several colors.
ONC eae sh
If the A or A indicator light turns on, check
the message in the instrument cluster.
The following indicator lights may be available,
depending on the vehicle equipment:

Red indicator lights
Central indicator light
=> page 7,
Instrument cluster
=> page 12
Safety belt
=> page 82

















Engine start system
=> page 108
Transmission
=> page 112
Drive system
=> page 117,
Electrical system
=> page 284
Charging system
=> page 137
Electromechanical parking brake
=> page 121
Electromechanical parking brake
=> page 122

Driving

— D (Drive)
Selecting a gear
Requirement: the ignition must be switched on.
— Bring the vehicle to a full stop and press the
brake pedal.
— Press the release button @ on the selector lev-
er.
—To select the nearest gear, move the selector
lever forward or back until you feel the first
pressure point.
—To skip a gear (for example, move from “D” to
“R”), move the selector lever past the pressure
point in the desired direction.
— The label next to the selector lever for the se-
lected gear will light up.
“N” (Neutral) gear
In the “N” gear, power is not transmitted to the
driving wheels. Use the “N” gear in a car wash
(with conveyor belts), for example.
If you unintentionally select “N” while driving
(faster than 1 mph (2 km/h)), you can also shift
back to “D” without pressing the brake pedal.
For safety reasons, the vehicle cannot be locked
when the transmission is in the "N” gear.
“Pp” (Park) gear
Requirement: the ignition must be switched on.
The vehicle is secured from rolling away by the
parking lock when in the “P” gear.
— Bring the vehicle to a full stop and press the
brake pedal.
— Press the “P” button (2) on the selector lever.
— The “P” next to the selector lever will light up.
“P” engages automatically if you switch the en-
gine off while the “D” or “R” gear is selected. If
you switch the engine off in “N”, “P” will engage
automatically after approximately 30 minutes.
If you want to switch to another gear from “P”,
the engine must be running.
If you cannot shift out of “P”, for example be-
cause the vehicle has no power, you may need to
use the emergency release for the parking lock
=> page 112.
110
Selecting the driving program
Various driving programs can be selected when in
the “D” gear. The programs influence when the
transmission shifts and how the accelerator ped-
al responds.
The selected driving program is displayed in the
instrument cluster.
—D (Drive): normal driving mode
—S (Sport): sporty driving mode
If you select the Dynamic mode in Audi drive se-
lect*, the “S” driving program will be activated.
When the ignition is switched off, the driving pro-
gram may be reset to “D”.
To switch between the current driving program
and “S”, push the selector lever toward the rear.
Plug-in hybrid drive system: Not all plug-in hy-
brid modes are available in the “S” driving pro-
gram. The driving program or plug-in hybrid
mode will be automatically adjusted if it is not
compatible with an operation.

ZA\ WARNING
— Before you start driving, check if the label
for the desired selector lever position next
to the selector lever is lit up.
— Secure the vehicle against rolling before ex:
iting the vehicle > page 108.
— Power is still transmitted to the wheels
when the engine is running at idle. To pre-
vent the vehicle from “creeping”, you must
keep your foot on the brake in all selector
lever positions (except "P" and "N") when
the engine is running.
— To reduce the risk of an accident, do not
press the accelerator pedal when changing
gears if the vehicle is stationary and the en-
gine is running.
— Never select the “R" or "P” gears while driv-
ing. Doing so could cause an accident.
— The vehicle can roll even if the ignition is
switched off.

G) Tips
If you shift between “D” and “R” within one
second, you do not need to press the brake >

Driving

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 118.
G) Tips
— Depending on the driving situation, the en-
gine may already stop when coasting before
the vehicle has come to a complete stop.
— If you 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.
118
G) Tips
— Press the brake pedal during a Stop phase
to keep the vehicle from rolling.
— The ignition will turn off if you press the
START ENGINE STOP] button during a Stop
phase.
— If you leave the vehicle briefly during a Stop
phase and then enter again, the driver's
door must be closed and the safety belt
must be fastened in order for the engine to
be able to restart.
— You can control if the engine will stop or not
by reducing or increasing the amount of
force you use to press the brake pedal. For
example, if you only lightly press on the
brake pedal in stop-and-go traffic or when
turning, the engine will not switch off when
the vehicle is stationary. If you press the
brake pedal harder, the engine will switch
off.
Starting and stopping the engine automat-
rely
Applies to: vehicles with Start/Stop system


The system checks if certain conditions are met
before and during the Stop phase, and deter-
mines if the engine stops and how long it re-
mains stopped. For example, if power usage is
high, the engine will not be stopped. Along with
other conditions, the following factors influence
the automatic engine start or stop:
— Environmental conditions (slopes, inclines, ele-
vation, temperature)
— Battery (charge status, temperature, power us-
age)
— Engine temperature
— Assist systems
— Driving behavior
Depending on the engine, the indicator light
may appear if the engine is not stopped.
Applies to: vehicles with Start/Stop system
Drive system: please start the vehicle manually >

Driving

— The braking force generated by the pressed
brake pedal is greater than the braking force
that
would be initiated by the system
— The ESC, the brake system, or the vehicle elec-
trical system is not functioning

ZA WARNING
— Only apply the brakes for the purpose of
cleaning the brake system when road and
traffic conditions permit. You must not en-
danger other road users and increase the
risk of an accident.
— Due to the risk of injury, only have an au-
thorized Audi dealer or authorized Audi
Service Facility work on the brake system.
Incorrect repairs could impair the function.
— Never let the vehicle roll while the engine is
stopped because this increases the risk of an
accident.
— During automatic braking maneuvers, the
brake pedal may move downward automati-
cally. To reduce the risk of injury, do not
place your foot under the brake pedal.
@) Note
— Never let the brakes “rub” by pressing the
pedal lightly when braking is not actually
necessary. This can cause the brakes to over-
heat and increases braking distance and
causes wear.
— Observe the important information for driv-
ing downhill > page 122. This especially ap-
plies when towing a trailer.
G@) Tips
— If you retrofit your vehicle with a front spoil-
er, wheel covers or similar items, make sure
that the air flow to the brakes is not ob-
structed. Otherwise the brake system can
overheat.

— Also refer to the information about brake
fluid > page 283.
Messages
GG i @ Brakes: malfunction! Stop vehicle
safely
120
There is a malfunction in the brake system. If
[S/ Bana B also turn on, there is a malfunc-
tion in the ABS, ESC, and braking distribution. If
the brake booster is not working, you have to use
much more force when braking the vehicle.
Do not continue driving. See an authorized Audi
dealer or authorized Audi Service Facility for as-
sistance. Read and follow the other safety pre-
cautions > A\.
fie 7 © 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 108.
Other indicator lights
When you switch the ignition on, the GG / @®
indicator light turns on briefly to check the func-
tion. If the indicator light does not turn on, there
is a system malfunction.
1f Ba / @ 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.

ZA WARNING
If a malfunction occurs in the ABS, ESC, and
braking distribution, interventions that >

Driving dynamic

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 108. 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.
& 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 compa-
rable to a vehicle without rear axle steering. Drive
carefully to an authorized Audi dealer or author-
ized Audi Service Facility to have the malfunction
corrected.
BS Steering lock: malfunction! Please contact
Service
There is a malfunction in the electronic steering
lock. Drive immediately to an authorized Audi
dealer or authorized Audi Service Facility to have
the malfunction repaired.
Dynamic steering: correcting steering wheel
position
The steering is reinitializing. The steering wheel
will move easily after starting the vehicle. Reiniti-
alization might be necessary if the steering wheel
was moved while the engine was switched off.
The display turns off if the initialization was suc-
cessful.

ZX WARNING
Do not tow your vehicle if there is a malfunc-
tion in the electronic steering lock because
this increases the risk of an accident.

128
G) Tips
— If there is a malfunction, the steering wheel
may be crooked when driving straight.
—If the a or & indicator light only stays on
for a short time, you may continue driving.
All wheel drive (quattro)
Applies to: vehicles with all wheel drive
The all-wheel drive system distributes the driving
power variably to the front and rear axle to im-
prove the driving characteristics. It works togeth-
er with selective wheel torque control, which can
activate when driving through curves
=> page 129.
The all-wheel drive system is designed for high
engine power. Your vehicle is exceptionally pow-
erful and has excellent driving characteristics
both under normal driving conditions and on
snow and ice. Always read and follow safety pre-
cautions > A\.

Z\ WARNING
— Even in vehicles with all wheel drive, you
should adapt your driving style to the cur-
rent road and traffic conditions to reduce
the risk of an accident.
— The braking ability of your vehicle is limited
to the traction of the wheels. In this way, it
is not different from a two wheel drive vehi-
cle. Do not drive too fast because this in-
creases the risk of an accident.
— Note that on wet streets, the front wheels
can “hydroplane’” if driving at speeds that
are too high. Unlike front wheel drive
vehicles, the engine RPM does not increase
suddenly when the vehicle begins hydro-
planing. Adapt your speed to the road condi-
tions to reduce the risk of an accident.
Sylar)
Applies to: vehicles with sport differential

The sport differential distributes the drive power
to the rear axle based on the situation. The goal
is a high level of agility and ability to accelerate >

4N0012721BF
Trailer towing

Trailer towing
Driving with a trailer
eT e e eeu)
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.

Z\ 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 > @®.
CG) 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.
Operating instructions
Towing capacity
Your vehicle can only be operated with class 1 or
class 2 trailers.
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 299. 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
147
>

4N0012721BF
Checking and Filling

Checking and Filling
Fuel
Types of gasoline
The correct gasoline grade is stated on the inside
of the fuel filler door.
The vehicle is equipped with a catalytic converter
and must only be driven with unleaded gasoline.
Audi recommends using TOP TIER Detergent Gas-
oline. For additional information on TOP TIER De-
tergent Gasoline, visit www.toptiergas.com.
The individual gasoline grades are differentiated
by octane ratings. This value is given with (R
+M)/2 equating to AKI or in RON.
The headings below match the sticker in the fuel
filler door (examples):
UNLEADED FUEL ONLY MIN. (R+M)/2 87
Regular / MIN. RON 91 Regular
Use regular gasoline with minimum 87 AKI /
91 RON > ©.
Audi recommends using premium gasoline with
minimum 91 AKI/ 95 RON to achieve the rated
horsepower and torque.
UNLEADED FUEL ONLY PREMIUM MIN. (R
+M)/2 91 / SUPER MIN. RON 95
Using premium gasoline with minimum 91 AKI /
95 RON is recommended.
If premium gasoline is not available, you can also
use regular gasoline 87 AKI / 91 RON. However
this does reduce the engine power slightly.
UNLEADED FUEL ONLY PREMIUM MIN. (R
+M)/2 93 / SUPER PLUS MIN. RON 98
Using premium plus gasoline with at least 93
AKI / 98 RON is recommended.
If no premium plus gasoline is available, you can
also use premium gasoline with 91 AKI /95 RON.
However this does reduce the engine power
slightly.
CG) Note
— Filling the tank just one time with leaded
fuel or other metallic additives will cause
permanent deterioration to the catalytic
converter function.
— When gasoline with an octane rating that is
too low is used, high speeds or heavy engine
load can lead to engine damage.
@ Tips
The vehicle may be filled with fuel that has a
higher octane rating than what is required by
the engine.
Gasoline mixture
Gasoline with alcohol or MTBE (Methyl-Tert-
Butyl-Ether)
You can use unleaded gasoline mixed with alco-
hol or MTBE (generally labeled as oxygenated
compounds) as long as the fuel meets the follow-
ing conditions:
Gasoline with methanol content (methyl alco-
hol or methanol)
— Anti-Knock Index is at least 87 AKI
—No more than 3% methanol
— More than 2% solvent
Gasoline with ethanol content (ethyl alcohol or
ethanol)
— Anti-Knock Index is at least 87 AKI
—No more than 15% ethanol
Gasoline with MTBE content
— Anti-Knock Index is at least 87 AKI
—No more than 15% MTBE
Gasoline adapted to the season
Many gasoline fuels are adapted to the seasons.
When the season changes, refueling at high-traf-
fic gas stations is recommended. It is more likely
that the gasoline will be suitable for the season
there.
@) Note
— Gasoline with methanol content that does
not meet the specified conditions may cause >
269

Checking and Filling

corrosion damage and damage to plastic or
rubber components in the fuel system.
— Do not use gasoline that does not meet the
specifications.
— If you are unable to find out if a specific gas-
oline mixture meets the specifications, ask
the gas station operator or their fuel suppli-
er.
— Do not use any gasoline mixture whose
composition cannot be identified.
— Audi does not assume any responsibility for
damage to the fuel system or for perform-
ance problems caused by using gasoline
mixtures different from those specified.
This type of damage also does not fall under
the New Vehicle Limited Warranty or under
the emissions control system warranty.
— If you notice a higher fuel consumption or
poor handling or performance problems due
to such gasoline mixtures, Audi recom-
mends fueling with unblended gasoline.
Gasoline additives
An important issue for many automobile manu-
facturers is combustion residue in the engine
that results from the use of certain fuels.
Although types of gasoline differ depending on
the manufacturer, there are similarities. Certain
substances in the gasoline may cause deposits in
the engine. Additives in the gasoline that should
keep the engine and fuel system clean do not all
function equally.
Audi recommends using TOP TIER Detergent Gas-
oline. For additional information on TOP TIER De-
tergent Gasoline, visit www.toptiergas.com.
If you use incorrect fuels over a long period of
time, the maximum engine performance may be
impaired by combustion residue.
@) Note
— Damage or malfunctions caused by the use
of incorrect types of gasoline are not cov-
ered by the New Vehicle Limited Warranty.
— Only gasoline additives that have been ap-
proved by Audi may be used.
270
Refueling
Messages
A Tank system: malfunction! Please contact
Service
There is a malfunction in the fuel tank system.
Drive to an authorized Audi dealer or authorized
Audi Service Facility immediately to have the
malfunction corrected.
Messages
Applies to: vehicles with plug-in hybrid drive
A Fuel filler door: malfunction! Unlock fuel
filler door manually. See owner's manual
There is a malfunction. You must manually un-
lock the fuel filler door > page 273.
Al Warning! Vehicle performance may be limit-
ed
The fuel tank is almost empty. You must antici-
pate a significant power loss. Refuel immediate-
ly.
& Please refuel and charge battery. Total
range: x mi (km)
or
f& Tank system: please refuel immediately and
charge battery. Total range: x mi (km)
If this indicator light turns on and this message
appears, refuel as soon as possible. Otherwise,
the high-voltage battery is drained > page 131.
AY Fuel filler door open. Please press button
again to refuel
Fueling is possible for a little while after pressing
the G) button. You must press the A button
again if the time limit is exceeded.