2021 AUDI A4 engine overheat

Instrument cluster

Adjusting the layout
Applies to: Audi virtual cockpit
Depending on the vehicle equipment, various lay-
outs may be available.
> Applies to: MMI: Select on the home screen:
SETTINGS > Display & brightness > Audi virtu-
al cockpit.
> To adjust the desired layout, press @).
Adjusting the additional display
Applies to: Audi virtual cockpit
Depending on the vehicle equipment, the addi-
tional displays that can be selected may vary.
> Applies to: MMI: Select on the home screen:
SETTINGS > Display & brightness > Audi virtu-
al cockpit > Configure.
> Select the desired additional display.
Reducing the display
Depending on the vehicle equipment, you can
hide the central area in the instrument cluster.
> Select on the instrument cluster: vehicle func-
tions tab > [=] button > Reduced display, or
> Press the VIEW button on the multifunction
steering wheel.
Coolant temperature
display
Applies to: vehicles with a coolant temperature indicator
The coolant temperature display @) > page 12
only functions when the ignition is switched on.
To reduce the risk of engine damage, please ob-
serve the following notes about the temperature
ranges.
Cold range
If only the LEDs at the bottom of the gauge turn
on, the engine has not reached operating tem-
perature yet. Avoid high engine speeds, full accel-
eration, and heavy engine loads.
Normal range
The engine has reached its operating tempera-
ture once the LEDs up to the center of the gauge
turn on. If the | indicator light in the instru-
14
ment cluster display turns on, the coolant tem-
perature is too high > page 227.
() Note
— Auxiliary headlights and other accessories in
front of the air intake impair the cooling ef-
fect of the coolant. This increases the risk of
the engine overheating during high outside
temperatures and heavy engine load.
— The front spoiler also helps to distribute
cooling air correctly while driving. If the
spoiler is damaged, the cooling effect will
be impaired and the risk of the engine over-
heating will increase. See an authorized
Audi dealer or authorized Audi Service Fa-
cility for assistance.
Tachometer
The tachometer @) > page 12 displays the engine
speed in revolutions per minute (RPM). The be-
ginning of the red zone in the tachometer indi-
cates the maximum permissible engine speed for
all gears once the engine has been broken in. Be-
fore reaching the red zone, you should shift into
the next higher gear, select the "D" or "S" selec-
tor lever position, or remove your foot from the
accelerator pedal.
Engine speed limitation
If the tA indicator light turns on, the engine will
be automatically limited to the RPM displayed in
the instrument cluster. This will protect the en-
gine components, for example during a cold start
or from overheating.
The engine speed limitation is deactivated if you
release the accelerator pedal while the engine is
at normal operating temperature.
If the engine speed limitation was activated by
an engine control malfunction, the By indicator
light also turns on. Make sure the engine speed
does not go above the speed displayed, for exam-
ple when downshifting. Drive to an authorized
Audi dealer or authorized Audi Service Facility im-
mediately to have the malfunction corrected. >

8W1012721BC
Driving


do not inadvertently press the accelerator
pedal and always shift into “P” when the ve-
hicle is stopped.
— If you leave the vehicle, switch the ignition
off and take the key with you. This is espe-
cially important when leaving persons or an-
imals in the vehicle. Otherwise, the vehicle
could start unintentionally, the parking
brake could release, or electronic equipment
could activate, which increases the risk of an
accident.
— No persons or animals should be left in a
locked vehicle. Locked doors make it more
difficult for emergency workers to enter the
vehicle, which puts lives at risk.
— If you do not begin driving immediately af-
ter releasing the brake pedal, your vehicle
may begin to roll backward. Press the brake
pedal
or set the parking brake immediately.
@) Note
If you have to stop on an incline, always press
the brake pedal to hold the vehicle in place to
reduce the risk of the vehicle rolling back-
ward. Do not try to hold the vehicle in place
by pressing and holding the accelerator pedal.
The transmission can overheat, which increas-
es the risk of damage.
Hill hold assist
If you take your foot off of the brake pedal when
driving on hills, the braking force will be held for
several seconds. At that time, you can start driv-
ing without the vehicle rolling backward.

Requirement: the driver's door must be closed,
the engine must be on, and the vehicle must be
traveling uphill.
> To activate hill hold assist, press and hold the
brake pedal for several seconds while the vehi-
cle is stationary.

ZA WARNING
— If you do not begin driving immediately af-
ter releasing the brake pedal, your vehicle
may begin to roll backward. Press the brake

pedal or set the parking brake immediately.

— The hill hold assist cannot hold the vehicle
on inclines in every scenario (for example,
on slippery or icy ground).
Gears and driving programs
(y—
(2—*


RAZ-0410:




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D/S
~~ NEI
Fig. 94 Center console: selector lever


The automatic transmission shifts automatically
depending on the selected gear and the current
driving style. When driving with a moderate driv-
ing style, upshifting early and downshifting late
will help to improve fuel economy. When driving
with a sporty driving style, the transmission per-
mits higher RPMs.
The gears are displayed next to the selector lever.
— P (Park)
—R (Reverse): driving in reverse
—N (Neutral): idle
—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.
97

8W1012721BC
Driving


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 107. This especially ap-
plies when towing a trailer.
@) Tips
— In vehicles with an electromechanical brake
booster, the resistance in the brake pedal
may vary depending on the driving situation
(such as if driver assistance system are ac-
tive).
— 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 229.
Ga 7 @ Brakes: malfunction! Stop vehicle
safely
There is a malfunction in the brake system. If
[S/ Bana fA 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\.
Hie / © 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 i @
indicator light turns on briefly to check the func-
tion. If the indicator light does not turn on, there
is a system malfunction.
file / © 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.

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

105

8W1012721BC
Driver assistance

Driver assistance
Cruise control system
Applies to: vehicles with cruise control system
The cruise control system assists the driver in
maintaining a constant speed above approxi-
mately 15 mph (20 km/h). The system maintains
the desired speed by braking and accelerating.

ZA WARNING
— Always pay attention to the traffic around
your vehicle when the cruise control system
is in operation. As the driver, you are always
responsible for controlling your vehicle
speed and the distance between your vehicle
and
other vehicles.
— For safety reasons, cruise control should not
be used in the city, in stop-and-go traffic, on
winding roads, and when road conditions are
poor (such as ice, fog, gravel, heavy rain,
and conditions that could lead to hydroplan-
ing), because this increases the risk of an ac-
cident.
— Switch the cruise control off temporarily
when driving in turning lanes, highway exits,
or in construction zones.
—To reduce the risk of an accident, you should
only resume the stored speed if it is suitable
for the current traffic conditions.

() Note
Before driving downhill a long distance ona
steep hill, decrease your speed and select a
lower gear. This makes use of the engine brak-
ing effect and reduces the load placed on the
brakes.
@ Tips
The brake lights turn on when the brakes are
applied automatically.
Switching the system on
Applies to: vehicles with cruise control system

BFV-0220



Fig. 105 Operating lever: switching the system on
Requirement: the ignition must be switched on.
> To switch the system on, pull the lever toward
you to position ©.
The Gia or i$) indicator light and the corre-
sponding message will appear in the instrument
cluster.

ZA\ WARNING
If the brakes are malfunctioning (for example,
overheating) while the cruise control system
is switched on, the regulating functions may
shut off automatically.



estate Rem lad lite: Rag ena)
speed
Applies to: vehicles with cruise control system
When the vehicle is stationary, you can preselect
the cruise control speed or activate the speed
while driving.
Requirement: the system must be switched on.
> To preselect a cruise control speed when the ve-
hicle is stationary, tap the lever toward @)/G)
=> page 127, fig. 105.
> To activate the cruise control speed, pull the
lever
toward position @ while driving.
> To set the current driving speed as the cruise
control speed, press the button @) on the lever.
The active cruise control speed is indicated with
the Gg or kl indicator light in the instrument
cluster. >
127

Checking and Filling

@ Tips
The fuel filler door on your vehicle does not
lock if you lock the vehicle from the inside us-
ing
the central locking switch.
Fuel filler door emergency release
Applies to: vehicles with manual fuel filler door release

If the central locking system malfunctions, the
fuel filler door can be unlocked manually.

Fig. 155 Right side trim panel in the luggage compart-
ment: opening the trim panel

Fig. 156 Luggage compartment: fuel filler door emergency
release
The emergency opening mechanism is located
behind the right side trim panel in the luggage
compartment.
> Open the cover in the side panel > fig. 155.
> To unlock the fuel filler door, loosen the red
loop from the retainer and then pull on the
loop carefully > fig. 1569©.
> Press on the left side of the fuel filler door to
open it > page 218, fig. 153.
@) Note
Only pull on the loop until you feel resistance.
You will not hear it release. If you continue to
220

pull, you could damage the emergency re-
lease mechanism.
Emissions control
system
General information
Z\ WARNING
The temperature of the exhaust system is
high, both when driving and after stopping
the engine.

— Never touch the exhaust tail pipes once they
have
become hot. This could result in burns.
— Do not park your vehicle over flammable
materials such as grass or leaves because
the high temperature of the emissions sys-
tem could start a fire.
— Do not apply underbody protectant in the
exhaust system area, because this increases
the risk of fire.
(er) 1 id (Rel Uae lg
Observe the safety precautions > page 220, Gen-
eral information.


The vehicle may only be driven with unleaded
gasoline, or the catalytic converter will be de-
stroyed.
Never drive until the tank is completely empty.
The irregular supply of fuel that results from that
can cause engine misfires. Uncombusted fuel
could enter the exhaust system, which could
cause overheating and damage to the catalytic
converter.
Malfunction Indicator Lamp (MIL)
If the S indicator light blinks or turns on, there
is a malfunction that is causing poor emissions
quality and that could damage the catalytic con-
verter. Drive slowly to an authorized Audi dealer
or authorized Audi Service Facility to have the
malfunction corrected.

8W1012721BC
Checking and Filling

Coolant loss usually indicates that there is a leak.
Immediately drive your vehicle to an authorized
Audi dealer or authorized Audi Service Facility
and have the cooling system inspected. If the
cooling system is not leaking, coolant loss can re-
sult from the coolant boiling due overheating
and then being forced out of the cooling system.

A WARNING
— The engine compartment in any vehicle is a
potentially dangerous area. Stop the engine,
switch the ignition off, and allow the engine
to cool before working in the engine com-
partment. Always follow the information
found in > page 221, General information.
— Never open the hood if you can see or hear
steam or coolant escaping from the engine
compartment. This increases the risk of
burns. The cooling system is under pressure.
When you no longer see or hear steam or
coolant escaping, you may open the engine
compartment with caution.
— When working in the engine compartment,
remember that the radiator fan can switch
on even if the ignition is switched off, which
increases the risk of injury.
— Coolant additive and coolant can be danger-
ous to your health. For this reason, store the
coolant in the original container and away
from children. There is a risk of poisoning.

® Note
Do not continue driving if the coolant expan-
sion tank is empty. Do not add any coolant,
because air could enter the cooling system
and damage the engine. See an authorized
Audi dealer or authorized Audi Service Facility
for assistance.
Brake fluid

BFV-0229]


Fig. 162 Engine compartment: cap on brake fluid reservoir
Observe the safety precautions > page 221, Gen-
eral information.
Checking the brake fluid level
The brake fluid reservoir is located under a cover
on the driver’s side.
> Lift the cover > page 223, fig. 159 at both
openings and remove it.
> Read the brake fluid level on the brake fluid res-
ervoir > page 223, fig. 159. The brake fluid lev-
el must be between the MIN and MAX markings
of.
The brake fluid level is monitored automatically.
Messages
EG / @ Brakes: stop vehicle and check brake
fluid level
Stop the vehicle and check the brake fluid level.
See an authorized Audi dealer or authorized Audi
Service Facility for assistance.
Changing the brake fluid
Brake fluid should be changed at regular inter-
vals. Have the brake fluid changed by an author-
ized Audi dealer or authorized Audi Service Facili-
ty. The authorized Audi dealer or authorized Audi
Service Facility will inform you of the replace-
ment intervals.

Z\ WARNING
— If the brake fluid level is below the MIN
marking, it can impair the braking effect and
driving safety, which increase the risk of an

229

8W1012721BC
Checking and Filling

that the vehicle can still be started, the electrical
equipment will be limited or switched off. Some
convenience functions, such as interior lighting
or power seat adjustment, may not be available
under certain circumstances. The convenience
functions will be available again when you start
the
engine.
Even when electrical equipment is switched off,
the equipment can still drain the battery if the
vehicle is not driven for Long periods of time.
Deep draining results in a chemical reaction that
destroys the inside of the battery. The battery
must be charged every month to prevent this
= page 232. Contact an authorized Audi dealer or
authorized Audi Service Facility for more infor-
mation.
Winter operation
Cold weather places an especially high load on
the 12 Volt vehicle battery. Have the battery
checked by an authorized Audi dealer or author-
ized Audi Service Facility before cold weather be-
gins.
so that it will not be destroyed by “freezing”
=> page 232, Charging the 12 Volt vehicle
battery.
— There are electrical components under the
cargo floor behind a trim panel that warm
up during operation. To reduce the risk of
the components overheating, do not store
objects such as blankets under the cargo
floor. If the components overheat, they will
switch off temporarily. This will be indicated
by a message that will be displayed in the
instrument cluster until the temperature re-
turns to normal.
12 Volt vehicle battery
Explanation of warnings:
Always wear eye protection.

forbidden.

ZA WARNING
— All work on the battery or electrical system
in your vehicle can result in injuries, chemi-
cal burns, accidents, or burns. Because of
this, all work must be performed only by an
authorized Audi dealer or authorized Audi
Service Facility.
— Never connect a charging cable or jump
start cable directly to the 12 Volt vehicle
battery. Only use the connections in the en-
gine compartment > page 232.

ZA WARNING
California Proposition 65 Warning:
— Battery posts, terminals and related acces-
sories contain lead and lead compounds,
chemicals known to the State of California
to cause cancer and reproductive harms.
Wash hands after handling.

@) Note
— If the vehicle will be parked for long periods
of time, protect the battery against the cold
A highly explosive mixture of gases can
form when charging batteries.

Always keep children away from battery
acid and the battery.
Battery acid is highly corrosive. Always
wear protective gloves and eye protection.
® Fire, sparks, open flame, and smoking are

@/ | Always follow the instructions in the oper-
(QO | ating manual.

@) For the sake of the environment

“© % Lead-acid batteries must be disposed of
using methods that will not harm the environ-
ment. Do not dispose of them in household
trash. They contain harmful substances, such
as sulfuric acid and lead, and also recyclable
raw materials. Contact an authorized Audi
dealer or authorized Audi Service Facility for
more information.
231

Emergency assistance

@) Note
The compressor must be switched off after six
minutes at the most to reduce the risk of
overheating. Let the compressor cool down
for several minutes before using it again.
Jump starting
You should only perform the steps that follow if
you have the necessary tools and technical ex-
pertise.
If the engine does not start because the vehicle
battery is drained, you can jump start your vehi-
cle using another vehicle. Jump start cables are
needed to do this.
Both vehicle batteries must have 12 V nominal
voltage. The voltage capacity (Ah) of the vehicle
battery that is giving power must not be less
than the capacity of the drained vehicle battery.
Jump start cable
Only use a jump start cable with a large enough
diameter. Note the manufacturer's specifica-
tions.
Only use a jump start cable with insulated termi-
nal clamps.
Positive cable - usually red.
Negative cable - usually black.

ZA\ WARNING
— A drained battery can freeze at tempera-
tures around 32 °F (0 °C). If the vehicle bat-
tery is frozen, it must be thawed before con-
necting the jump start cables. If it is not,
the risk of an explosion and chemical burns
increases. After jump starting the vehicle,
drive to an authorized Audi dealer or author-
ized Audi Service Facility immediately to
have the vehicle battery checked.
— Read the warnings when working in the en-
gine compartment > page 221.
— Handling the jump start cables incorrectly
may cause the vehicle battery to explode
and lead to serious injuries.

268
@) Note
Jump start cables can cause considerable
damage to the vehicle electrical system if
they are connected incorrectly.
@) Tips
— There must be no contact between the
vehicles, or else voltage could flow when
connecting the positive terminal and drain
the vehicle battery of the vehicle providing
the jump start.
— The drained vehicle battery must be con-
nected correctly to the electrical system.
— Switch off electrical equipment that is not
needed.

Both jump start cables must be connected in the
correct order.

Fig. 179 Engine compartment: connectors for jump start
cables or a charger



Fig. 180 Engine compartment: connectors for jump start
cables or a charger
The jump start cable connections are located in
the engine compartment.
Follow the information about the vehicle battery
=> page 230. >