check engine AUDI A5 2021 Owner's Manual

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.

ZA 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 230, 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.
238
Brake fluid

BFV-0229]


Fig. 170 Engine compartment: cap on brake fluid reservoir
Observe the safety precautions > page 230, 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 232, fig. 167 at both
openings and remove it.
>» Read the brake fluid level on the brake fluid res-
ervoir > page 232, fig. 167. The brake fluid lev-
el must be between the MIN and MAX markings
oA.
The brake fluid level is monitored automatically.
Messages
EG i @ 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.

ZA 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

8W7012721BB
Checking and Filling


accident. Do not continue driving. See an au-
thorized Audi dealer or authorized Audi
Service Facility for assistance.
— If the brake fluid is old, bubbles may form in
the brake system during heavy braking. This
could impair braking performance and driv-
ing safety, which increases the risk of an ac-
cident.
— The brake fluid in your vehicle must meet
the standard VW 501 14 and is available at
an authorized Audi dealer or authorized
Audi Service Facility. If this brake fluid is not
available, another high-grade brake fluid of
equivalent quality may be used, and it must
meet
the U.S. Federal Motor Vehicle Stand-
ard (FMVSS) 116 DOT 4, Class 6.

Switch off all electrical equipment that is not
needed. If necessary, some equipment will be
switched off automatically. Vehicle functions or
driving stability may be limited. Drive to an au-
thorized Audi dealer or authorized Audi Service
Facility immediately.
= Electrical system: low battery charge. Bat-
tery
will be charged while driving
The starting ability may be impaired.
If this message turns off after a little while, the
vehicle battery has charged enough while driving.
If this message does not turn off, drive immedi-
ately to an authorized Audi dealer or authorized
Audi Service Facility.

@) Note
— If the brake fluid level is above the MAX
marking, brake fluid may leak out over the
edge of the reservoir and result in damage
to the vehicle.
— Do not allow any brake fluid to come into
contact with the vehicle paint, because it
will corrode the paint.
Electrical system
If the = f B or = indicator light turns on,
there is a malfunction in the power supply, the
battery, or the vehicle electrical system.
= f B Electrical system: malfunction! Safely
stop vehicle
Do not continue driving and switch the ignition
off > A\. See an authorized Audi dealer or author-
ized Audi Service Facility for assistance.
= Electrical system: malfunction! Restart not
possible. Please contact Service
If you switch the ignition off, you will not be able
to restart the vehicle. Vehicle functions or driving
stability may be limited. Drive to an authorized
Audi dealer or authorized Audi Service Facility im-
mediately.
= Electrical system: malfunction! Please con-
tact Service
Z\ WARNING
When there is an electrical system malfunc-
tion, vehicle functions may not work and driv-
ing stability may be limited, which increases
the risk of an accident. Do not continue driv-
ing and switch the ignition off. See an author-
ized Audi dealer or authorized Audi Service Fa-
cility for assistance.


Battery
lala Meme cd)
Because of the complex power supply, all work on
batteries such as disconnecting, replacing, etc.,
should only be performed by an authorized Audi
dealer or authorized Audi Service Facility > A\.
Multiple batteries with different technologies
may be installed in your vehicle:
— Vehicle battery (for example, for starting the
engine, basic power supply) > page 240, 12
Volt vehicle battery or > page 241, Other bat-
tery types
— Auxiliary battery (for example, for recuperation
or optional equipment) > page 241, Other bat-
tery types
Not running the vehicle for long periods of
time
The battery will gradually drain if the vehicle
does not run for long periods of time. To ensure
239
>

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 241. 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 241, 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.

ZX 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 241.

Z\ 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
240
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-
(Q | 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.

8W7012721BB
Checking and Filling

Other battery types
Explanation of warnings:
Fire, sparks, open flame, and smoking are
& forbidden.
Always keep children away from battery
@) acid and the battery.


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

Z\ WARNING
All work on the batteries must only be per-
formed by an authorized Audi dealer or au-
thorized Audi Service Facility.
— Gases that escape from these different bat-
tery types can be poisonous or flammable.
— The contents of these battery types can be
corrosive. If any battery contents come into
contact with the skin, flush the affected
area for at least 15 minutes with clean wa-
ter. Then wash the affected area with soap.
Have the affected area examined by a medi-
cal professional.
@) Note
Components must not be connected to the
battery terminals and wires on these battery
types because this increases the risk of dam-
age, for example due to overvoltage.

@ For the sake of the environment

“5 J These types of batteries must be dis-
posed of using methods that will not harm
the environment. Do not dispose of them in
household trash. They contain harmful sub-
stances and recyclable raw materials. Contact
an authorized Audi dealer or authorized Audi
Service Facility for more information.
ing the 12 Volt vehicle battery

Fig. 171 Engine compartment: connectors for a charger or
jump start cables
Observe the safety precautions > page 230, Gen-
eral information, > /\ in Battery general infor-
mation on page 240 and > /A\.
Requirement: only use chargers with a maximum
charging current of 14.8 volts. The battery ca-
bles remain connected.
The charging cable connections are located in the
motor compartment. The ground point ©) is al-
ways located on the vehicle body.
>» Switch off the ignition and all electrical equip-
ment.
> Open the hood > page 231.
> Press the release lever on the positive terminal
and fold the cover upward > fig. 171.
> Clamp the charger terminal clamps to the jump
start pins according to the instructions. (Hex
head bolt under a cover (), ground point on the
vehicle body ©).
> Insert the power cable for the charging device
into the socket and switch the device on.
>» At the end of the charging process, switch the
charger off and pull the power cable out of the
socket.
> Remove the charging device terminal clamps.
> Close the cover on the positive terminal.
> Close the hood = page 231.

ZA WARNING
— 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 241. >

241

Checking and Filling


— A highly explosive mixture of gases can form
when charging batteries. Only charge the
battery in well-ventilated areas.
— A drained battery can freeze at tempera-
tures around 32 °F (0 °C). Do not charge or
use a frozen or thawed battery. If ice forms,
the battery housing can crack and battery
electrolyte can leak out, which increases the
risk of an explosion and chemical burns.
Contact an authorized Audi dealer or author-
ized Audi Service Facility for more informa-
tion.
— Do not connect or disconnect the charging
cable while charging because this increases

the risk of an explosion.

G) Tips
Read all of the manufacturer's instructions
for the charger before charging the battery.
Windshield washer
system

B8W-0125


Fig. 172 Engine compartment: washer fluid reservoir cap
Observe the safety precautions > page 230, Gen-
eral information.
The windshield washer reservoir © contains the
cleaning solution for the windshield/rear win-
dow* and the headlight washer system*
> fig. 172, > page 232. The reservoir capacity
can be found in > page 300.
To reduce the risk of lime scale deposits on the
spray nozzles, use clean water with low amounts
of calcium. Always add window cleaner to the wa-
ter. When the outside temperatures are cold, an
anti-freezing agent should be added to the water
so that it does not freeze.
242
Messages
gs Please add washer fluid
Fill the washer fluid for the windshield washer
system and the headlight washer system* when
the ignition is switched off.
C) Note
— The concentration of anti-freezing agent
must be adjusted to the vehicle operating
conditions and the climate. A concentration
that is too high can lead to vehicle damage.
— Never add radiator anti-freeze or other addi-
tives to the washer fluid.
— Do not use a glass cleaner that contains
paint solvents, because this could damage
the paint.
Service interval display
The service interval display detects when your ve-
hicle is due for service.
The service interval display works in two stages:
— Inspection or oil change reminder: after driv-
ing a certain distance, a message appears in the
instrument cluster display each time the igni-
tion is switched on or off. The remaining dis-
tance or time is displayed briefly.
— Inspection or oil change due: if your vehicle
has reached an inspection or oil change interval
or both intervals at the same time, the mes-
sage Inspection due! or Oil change due! or Oil
change and inspection due! appears briefly af-
ter switching the ignition on or off.
Checking service intervals
You can check the remaining distance or time un-
til the next oil change or next inspection in the
Infotainment system.
Applies to MMI: Select on the home screen: VE-
HICLE > Settings & Service > Service intervals.
Resetting the indicator
An authorized Audi dealer or authorized Audi
Service Facility will reset the service interval dis-
play after performing service.

8W7012721BB
Checking and Filling

If you have changed the oil yourself, you must re-
set the oil change interval.
Applies to: MMI: To reset the display, select on
the home screen: VEHICLE > Settings & Service
> Service intervals.
@) Note
— Only reset the oil change indicator if the oil
was changed.
— Following the service intervals is critical to
maintaining the service life and value of
your vehicle, especially the engine. Even if
the mileage on the vehicle is low, do not ex-
ceed the time for the next service.
243

8W7012721BB
Wheels

@) Tips
—If tires are replaced, the sensors and valves
do not need to be removed or replaced. Only
replace the valve stem and, if necessary, the
valve and the wheel electronics. If you have
questions, see an authorized Audi dealer or
authorized Audi Service Facility.
— An incorrect display or a malfunction in the
tire pressure monitoring system can occur
after using the tire mobility kit*. Have the
sensors replaced by an authorized Audi
dealer or authorized Audi Service Facility.
— The system complies with United States FCC
regulations and ISED regulations
=> page 297.
Disp Rte eee See ed
Applies to: vehicles with tire pressure monitoring system
Requirement: you must be driving the vehicle.
> Applies to MMI: Select on the home screen: VE-
HICLE > Settings & Service > Tire pressure
monitoring > Display tire pressure.
The current tire pressures are shown in green,
yellow, or red numbers:
— Green: the current tire pressure and the speci-
fied tire pressure are approximately the same.
— Yellow: the current tire pressure is lower than
the specified tire pressure.
— Red: the current tire pressure is much lower
than the specified tire pressure.
The specified tire pressure is the last tire pressure
that was stored > page 265.
Note that the tire pressure also depends on the
temperature of the tire. The tire pressure increas-
es as the engine becomes warmer while driving.

Z\ WARNING
Read and follow the important information
and notes > page 264.
@ Tips
The tire pressure or temperature is not dis-
played while the vehicle is stationary and in

adaptation mode. Dashes --.-- are shown in
place of the pressure and temperature.
(1) Tire pressure loss
Applies to: vehicles with tire pressure monitoring system
If the @ indicator light turns on, the tire pres-
sure is too low compared to the specified pres-
sure. Check and store the tire pressure(s) the
next time it is possible > page 265.
@® Flat tire! Safely stop vehicle. Please check all
tires and store pressures in MMI
If the indicator light turns on and the message
appears, the tire pressure has reached a critical
level compared to the specified pressure. Avoid
unnecessary steering and braking maneuvers.
Adapt your driving style to the situation. Stop as
soon as possible and check the tire(s). If it is pos-
sible to continue driving, see an authorized Audi
dealer or authorized Audi Service Facility immedi-
ately and have your tire(s) repaired or replaced.

ZA WARNING
Read and follow the important information
and notes > page 264.
Storing new tire pressures
Applies to: vehicles with tire pressure monitoring system

The tire pressure specifications must be stored
correctly for the tire pressure monitoring system
to function reliably.
It is always necessary to store the tire pressures
when the tire pressures are modified, for exam-
ple due to a change in load or when new sensors
are installed.
> Before storing the tire pressures, make sure the
tire pressures of all four tires meet the speci-
fied values and are adapted to the load
=> page 254, fig. 176. Only correct and store
the pressure in tires whose temperature is ap-
proximately the same as the ambient tempera-
ture. If the temperature of the tire is higher
than the ambient air temperature, the tire
pressure must be increased approximately
3 PSI (0,2 bar) above the value on the sticker.
> Switch the ignition on.
265

Emergency assistance

> Reinstall the caps on the wheel bolts if necessa-
ry.
> Store the vehicle tool kit in its designated
place.
> If the removed wheel does not fit in the spare
wheel well, store it securely in the luggage
compartment > page 92.
> Check the tire pressure on the installed wheel
as soon as possible.
> Correct the tire pressure and store it in the MMI
=> page 263 or > page 265.
> The wheel bolt tightening specification must be
90 ft lbs (120 Nm). Have it checked as soon as
possible with a torque wrench. Drive carefully
until then.
> Have the faulty wheel replaced as quickly as
possible.
Space-saving spare tire
Applies to: vehicles with space-saving spare tire (compact
spare tire)
The spare tire is intended for short-term use only.
Have the damaged tire checked and replaced if
necessary by an authorized Audi dealer or author-
ized Audi Service Facility as soon as possible.
There are some restrictions on the use of the
compact spare tire. The compact spare tire has
been designed specifically for your type of vehi-
cle. Do not replace it with the spare tire from an-
other type of vehicle.
The compact spare tire is located in the luggage
compartment under the cargo floor cover
=> page 274.
The tire pressure must be adjusted to a specified
value listed on the tire pressure sticker
= page 254, fig. 176.
Snow chains
For technical reasons, the use of snow chains on
the compact spare tire is not permitted.
If you have to drive with snow chains and a front
tire fails, mount the spare tire in place of a rear
tire. Install the snow chains on the rear tire that
280
you removed, and install that in place of the
front tire that failed.

ZA\ WARNING
— After installing a spare tire, the tire pressure
must be checked as soon as possible.
—Do not drive faster than 50 mph (80 km/h)
with a compact spare tire. Driving faster
than that increases the risk of an accident.
—To reduce the risk of an accident, avoid hard
acceleration or braking and driving fast
around curves with the compact spare tire.
—To reduce the risk of an accident, never drive
with more than one compact spare tire.
— Normal summer or winter tires must not be
mounted on the compact spare wheel rim.
@) Note
Secure the spare tire in the spare tire well us-
ing
the handwheel in order to reduce the risk
of damage to other components.

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.

8W7012721BB
Emergency assistance


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 230.
— Handling the jump start cables incorrectly
may cause the vehicle battery to explode
and lead to serious injuries.

() 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. 187 Engine compartment: connectors for jump start
cables or a charger


Fig. 188 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 239.
Connecting the positive cable (red) to the
positive terminal
> Open the cover on the positive terminal
> fig. 187.
1. Attach one end of the positive cable (red) to
the jump-start pin @ © fig. 188 on your vehi-
cle.
2. Attach the other end of the positive cable
(red) to the positive terminal @) on the pow-
er source.
Connecting the negative cable (black) to the
negative terminal
3. Attach one end of the negative cable (black)
to the negative terminal @) on the power
source.
4. Attach the other end of the negative cable
(black) to the jump-start pin @ on the vehi-
cle.
Starting the engine
> Start the engine in the vehicle giving the charge
and let it run at idle.
> Now start the engine in your vehicle, which has
the
drained battery.
> If the engine does not start, stop the starting
procedure after 10 seconds and then repeat it
after approximately 30 seconds.
> Turn on the rear window defogger in your vehi-
cle in order to reduce any voltage peaks that
may occur when disconnecting the jump start
cables. The headlights must be switched off. = >
281

Fuses and bulbs

@) Note
If a new fuse burns out again shortly after you
have installed it, have the electrical system
checked as soon as possible by an authorized
Audi dealer or authorized Audi Service Facili-
ty.
G@) Tips
— The following table does not list fuse loca-
tions that are not used.
— Some of the equipment listed in the follow-
ing tables applies only to certain model ver-
sions or certain optional equipment.

Fig. 193 Driver's footwell (left-hand drive vehicle): fuse
panel with plastic clip
286
3 2
= & a

a
Ss $
2 8

Fig. 194 Front passenger's footwell (right-hand drive vehi-
cle): fuse panel with plastic clip

Fuse panel


No. | Equipment

Catalytic converter heating

2 |Engine components

Exhaust doors, fuel injectors, radiator in-
let, crankcase housing heating

Vacuum pump, hot water pump, NOx sen-
4 |sor, particulate sensor, biodiesel sensor,
exhaust doors

Brake light sensor

6 | Engine valves, camshaft adjustment

Heated oxygen sensors, mass airflow sen-
sor, water pump

Water pump, high pressure pump, high
8 | pressure regulator valve, temperature
valve, engine mount

Hot water pump, motor relay, 48 V drive-
train generator, 48 V water pump

10 | Oil pressure sensor, oil temperature sensor

Clutch position sensor, 48 V drivetrain
11 | generator, water pump, 12 V drivetrain
generator

12 | Engine valves, engine mount


13 | Engine cooling