2021 AUDI A4 check engine

8W1012721BC
Checking and Filling

The hood latch is not locked correctly. Stop im-
mediately and close the hood.
K WARNING
— Never open the hood when there is steam or
coolant escaping from the engine compart-
ment, because there is a risk that you could
be burned. Wait until no steam or coolant is
escaping.
— For safety reasons, the hood must always be
latched securely while driving. Because of



NY [1
this, always check the hood after closing it
to make sure it is latched correctly. The hood
is latched if the front corners cannot be lift-
ed.
— If you notice that the hood is not latched
while you are driving, stop immediately and
close it, because driving when the hood is
not latched increases the risk of an accident.



Fig. 159 Typical location of the reservoir and the engine oil filler opening (example)
Observe the safety precautions > page 221.
@ Washer fluid reservoir (>) > page 233
) Jump start points: (+) under the cover
= page 232, Charging the 12 Volt vehicle
battery > page 268, Preparation

Engine oil filler opening (%27) > page 225

Sticker* for engine oil specifications
=> page 224


) Coolant expansion tank (-£) > page 228
Brake fluid reservoir (OC) > page 229
The coolant expansion tank and the engine oil
filling opening may be located in different places
within
the engine compartment, depending on
the engine version.
223

Checking and Filling

Engine oil
If the engine oil level is too low
If you need to add engine oil, use an oil that is
listed on the sticker. The sticker is located at the
front of the engine compartment > page 223,
fig. 159. When using the engine oil listed on the
sticker, you can adjust the oil level as often as
needed.
If engine oil that meets the recommended speci-
fication is not available, in an emergency you
may add a maximum of 1 quart (1 liter) of
ACEA C3 or API SN engine oil one time until the
next oil change.
For more information on the correct engine oil
for your vehicle, contact an authorized Audi deal-
er or authorized Audi Service Facility. Have the oil
changed by an authorized Audi dealer or author-
ized Service Facility.
G) Tips
Audi recommends using engine oils provided
by Audi Genuine Parts.
Messages
Hiturn off engine. Oil pressure too low
Stop driving and switch the engine off. Check the
engine oil level > page 225.
— If the engine oil level is too low, add engine oil
=> page 225. Only continue driving once the in-
dicator light turns off.
— If the engine oil level is correct and the indica-
tor light still turns on, turn the engine off and
do not continue driving. See an authorized Audi
dealer or authorized Audi Service Facility for as-
sistance.
Applies to: vehicles with oil level warning
2 Please add oil immediately.
Stop driving and switch the engine off. Check the
engine oil level > page 225 and add engine oil
immediately > page 225.
3 Add max. x qt (x l) oil. You can continue
driving
224
Add the amount of oil shown immediately
=> page 225.
EA Please reduce oil level
There is too much oil in the engine and there is a
risk of damaging the catalytic converter or en-
gine. Drive to an authorized Audi dealer or au-
thorized Audi Service Facility immediately to have
engine oil extracted if necessary. Avoid high en-
gine speeds, full acceleration, and heavy engine
loads.
3 Oil level sensor: oil change necessary. Please
contact Service
Fuel has entered the engine oil. This will cause
the engine oil level to rise slowly and the engine
oil quality to decrease. Do not extract engine oil
to reduce the level, because this will increase the
risk of engine damage. Drive to an authorized
Audi dealer or authorized Audi Service Facility im-
mediately to have engine oil extracted.
& Oil level system: malfunction! Please con-
tact Service
The sensor that checks the engine oil level has
malfunctioned. Drive immediately to an author-
ized Audi dealer or authorized Audi Service Facili-
ty to have the malfunction repaired.
2 Oil pressure sensor: malfunction! Please
contact Service
The sensor that checks the engine oil pressure
has malfunctioned. Drive immediately to an au-
thorized Audi dealer or authorized Audi Service
Facility to have the malfunction repaired.
i Please drive to warm up engine
Fuel has entered the engine oil, either due to low
outside temperatures or frequent short drives.
Drive until the engine is warm so that the fuel in
the engine oil will evaporate. Avoid high engine
speeds, full accelerating, and heavy engine loads
when doing this.
G) Tips
The oil pressure warning =} is not an oil level
indicator. Always check the oil level regularly.

8W1012721BC
Checking and Filling
Checking the engine oil level and the road conditions. The dilution of oil
from condensation or fuel residue as well as
the age of the oil also play a role. Because

The engine oil level can be checked in the MMI.
Observe the safety precautions > page 221, Gen- engine wear increases with mileage, oil con-
eral information. sumption will increase again over time until
it may be necessary to replace worn compo-
> Park the vehicle on a level surface.
> Shut the engine off when it is warm.
> Switch only the ignition back on.
> Wait approximately two minutes.
> Applies to MMI: Select on the home screen: VE-
HICLE > Settings & Service > Oil level.
> Read the oil level in the display. Add engine oil
if the bar in the oil level indicator is just below
“min” > page 225.
nents.
— Because all these variables play a role, it is
not possible to define an oil consumption
standard. Therefore, the oil level must be
checked regularly.
— If you believe that your engine has in-
creased its oil consumption, contact an au-
thorized Audi dealer or authorized Audi
Service Facility to determine the cause.
Please note that an exact oil consumption
© Note measurement must be done with the neces-
If the engine oil level is too low or too high, sary care and accuracy and may take time.
there is a risk of engine damage. An authorized Audi dealer or authorized
Audi Service Facility is trained in accurately
@ Tips measuring the oil consumption.
The oil level indicator in the display is only an — You can find information on engine oil and
informational display. If the oil level is too engine oil capacities for the USA at www.
low, a minimum oil warning appears in the in- audiusa.com/help/maintenance, or for Can-
strument cluster. Add oil and close the hood. ada at www.audi.ca/ca/web/en/
The current oil level will be displayed on the customer-area/care-and-maintenance/
MMI the next time the ignition is switched on. audi-service-schedules.html, or call
800-822-2834.
@ Tips
The engine oil consumption may be up to Adding engine oil
0.5 quart/600 miles (0.5 liter/1,000 km), de-
pending on driving style and operating condi-
tions. Consumption may be higher during the
first 3,000 miles (5,000 km). The engine oil
level must be checked regularly. It is best to
check each time you refuel your vehicle and
before long drives.

B8K-2120
— Because of the lubrication and cooling of
the engine, combustion engines consume
oil. The oil consumption varies depending
on the engine and may change during the
service life of the engine. Engines generally
consume more oil at the beginning during Observe the safety precautions > page 221, Gen-
the break-in period. Then oil consumption eral information.
stabilizes after the break-in period.
— Under normal conditions, oil consumption
depends on the quality and viscosity of the
oil, the engine RPM, the climate conditions,



Fig. 160 Engine compartment: engine oil filler opening
cover
> Turn the engine off.
> Open the hood & page 222.
225

Checking and Filling

> Unscrew the cap %~ for the engine oil filler
opening > fig. 160.
> Carefully add 0.5 quart (0.5 liter) of the correct
oil > page 224.
> Close the engine oil filler opening cap.
> Close the hood > page 222.
> Restart the ignition after two minutes and read
the current oil level in the MMI > page 225,
Checking the engine oil level.
> Applies to: using engine oil that meets the rec-
ommended specification: Add some more en-
gine oil again if necessary.

ZA\ WARNING
— When adding oil, do not let oil drip onto hot
engine components. This increases the risk
of a fire.
— You must close the cap on the oil filler open-
ing correctly so that oil does not leak out on-
to the hot engine and exhaust system when
the engine is running, because this is a fire
hazard.
— Always clean skin thoroughly if it comes into
contact with engine oil.
—
Engine oil is poisonous and must be kept out
of reach of children.
— Store the engine oil securely in the original
container.

@) Note
— The New Vehicle Limited Warranty does not
cover damage or malfunctions if the recom-
mended intended use of the vehicle and
maintenance measures listed in the Audi
Owner's Manual and the Warranty & Main-
tenance Booklet were not followed.
— Only use high-grade engine oil that explicit-
ly meets the Audi oil quality standard for
your vehicle. Using another oil may cause
severe vehicle damage.
— Do not mix any additives with the engine oil.
Additives may cause engine damage that is
not covered by your New Vehicle Limited
Warranty.
226
@) For the sake of the environment
— Oil should never enter the sewer system or
come into contact with the ground.
— Follow the legal regulations in the country
where you are located when disposing of
empty oil containers.
Changing engine oil
Audi recommends having the oil changed at an
authorized Audi dealer or authorized Audi Serv-
ice Facility.
Observe the safety precautions > page 221, Gen-
eral information.
The engine oil must be changed at the intervals
specified in the Warranty & Maintenance Book-
let. This is very important because the lubrication
function of the oil gradually declines during regu-
lar vehicle operation.
The engine oil should be changed more frequent-
ly under certain circumstances. Have the oil
changed more frequently if you often drive short
distances, your vehicle is predominantly in stop-
and-go traffic situations, is in very dusty environ-
ments, or is operated for long periods of time in
temperatures below zero.
Cleansing additives in the oil make fresh oil ap-
pear darker after the engine has run briefly. This
is normal and no reason to change the engine oil
more frequently than recommended.
Because correctly disposing of engine oil is diffi-
cult and special tools and technical knowledge
are needed for an oil change, Audi recommends
having your engine oil changed by an authorized
Audi dealer or authorized Audi Service Facility.
If you change the engine oil yourself, please note
the following important information:

Z\ WARNING
If you change the engine oil on the vehicle
yourself, the following precautions must be
followed:
— Wear protective eyewear.
— Due to the risk of scalding, allow the engine

to cool down sufficiently. >

8W1012721BC
Checking and Filling


— Maintain enough distance when you are re-
moving the oil drain plug. While doing this,
keep your forearm parallel to the ground to
reduce the risk of hot oil dripping down your
arm.
— Drain the oil into a container designed for
this purpose that is large enough to hold the
full amount of oil in your engine.
— Engine oil is poisonous. Always store out of
reach of children.
— Prolonged contact of used engine oil with
the skin may cause skin damage. Always
wash oil off immediately with soap and wa-
ter to protect your skin.
@) Note
Do not mix any additives with the engine oil.
Additives may cause engine damage that is
not covered by your New Vehicle Limited War-
ranty.

() For the sake of the environment
— Before changing the engine oil, make sure
you can dispose of the used engine oil cor-
rectly.
— Engine oil must always be disposed of cor-
rectly. Do not dump it in the yard, in the for-
est, or in open water, river channels, or sew-
ers.
— Have your used engine oil recycled by bring-
ing it to a used oil collection site or contact
a gas station.
Cooling system
The engine cooling system is filled with a mixture
of purified water and coolant additive at the fac-
tory. This coolant must not be not changed.
The coolant level is monitored using the B indi-
cator light. However, occasionally checking the
coolant level is recommended.
Messages
/_E| Turn off engine and check coolant level. See
owner's manual
The coolant level is too low.
Stop driving and switch the engine off. Check the
coolant level > page 228.
— If the coolant level is too low, add coolant
=> page 228. Only continue driving once the in-
dicator light turns off.
& Coolant temperature: too high. Please let
engine run while vehicle is stationary
Let the engine run at idle for a few minutes to
cool off, until the indicator light turns off.
— If the indicator light does not turn off, do not
continue driving the vehicle. See an authorized
Audi dealer or authorized Audi Service Facility
for assistance.
| Coolant system: malfunction! Please turn
off engine
Do not continue driving, shut the engine off, and
switch the ignition off.
— See an authorized Audi dealer or authorized
Audi Service Facility for assistance.
Coolant additive
The coolant additive is made of anti-freezing and
corrosion protection agents. Only add the follow-
ing coolant additives mixed with distilled water.

Coolant additive Specification


Gl12evo TL774L

The amount of coolant additive that needs to be
mixed with water depends on the climate where
the vehicle will be operated. If the coolant addi-
tive percentage is too low, the coolant can freeze
and damage the engine.


Coolant Freeze protec-
additive tion
Warm min. 40% min. -13 °F
regions max. 45% 25 °C)
Cold min. 50% max. -40 °F
regions max. 55% (-40 °C)

@) Note
— Before the start of winter, have an author-
ized Audi dealer or authorized Audi Service
227
>

Checking and Filling

Facility check if the coolant additive in your
vehicle matches the percentage appropriate
for the climate. This is especially important
when driving in colder climates.
— If the G12evo coolant additive is not availa-
ble in an emergency, do not add any other
additive. You could damage the engine. If
this happens, only use distilled water and
restore the correct mixture ratio with the
specified coolant additive as soon as possi-
ble.
— Only refill with new coolant.
— Radiator sealant must not be mixed with
the coolant.
— You can continue driving if the permitted
G12evo coolant additive was not added.
However, go to an authorized Audi dealer or
authorized Audi Service Facility immediately
to have the coolant replaced to reduce the
risk of engine damage.
— Due to the risk of engine damage, the cool-
ing system should only be refilled by an au-
thorized Audi dealer or authorized Audi
Service Facility. An authorized Audi dealer or
authorized Audi Service Facility can also pro-
vide you with important information about
the recommended coolant additive.
(Gitta diet lis

RAZ-0540,



Fig. 161 Engine compartment - Coolant expansion tank:
@ cover with release button; @) markings
Observe the safety precautions > page 221, Gen-
eral information.
Checking the coolant level
> Park the vehicle on a level surface.
> Switch the ignition off.
> Open the hood > page 222.
228
The coolant expansion tank for some engines is
located in the water drip tray under a cover. If
necessary, remove the cover that is located under
the windshield wiper on the front passenger's
side.
> Check the coolant level in the coolant expan-
sion tank > page 223, fig. 159 using the outer
markings (2) > fig. 161. The coolant level must
be between the markings (2) when the engine is
cold. When the engine is warm it can be slight-
ly above the upper marking.
» Applies to: vehicles with 6-cylinder engine:
There is a float located in the coolant expansion
tank. Read the coolant level using the coolant
level float. When the engine is cold, the float
must be located between the MIN marking and
the edge of the filler opening on the coolant ex-
pansion tank.
> When you add coolant to the expansion tank,
please refer to > page 227, Cooling system.
Adding coolant
Requirement: there must be a residual amount of
coolant in the expansion tank >@).
If you must add coolant, use a mixture of water
and coolant additive. Audi recommends mixing
the coolant additive with distilled water.
> Allow the engine to cool.
> Place a large, thick towel on the coolant expan-
sion tank cap.
> Push the release button @ > fig. 161 on the
cap and carefully turn it to the left until you
feel resistance > /\.
> Push the release button again and remove the
cap completely.
» Add coolant in the correct mixture ratio
=> page 227 up to the MAX marking. Or, in
vehicles with a 6-cylinder gasoline engine, the
float must be located between the MIN mark-
ing and the edge of the filler opening on the
coolant expansion tank.
> Make sure that the fluid level remains stable.
Add more coolant if necessary.
> Vehicles with 6-cylinder engine: if necessary,
press the float into the coolant expansion tank
using the cover.
> Turn the cap to the right to tighten it until you
feel resistance a second time.

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

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.
z= 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 = / B or = indicator light turns on,
there is a malfunction in the power supply, the
battery, or the vehicle electrical system.
mz / 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
230
ZA\ 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
ela lame (Tem eeecela)
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 231, 12
Volt vehicle battery or > page 232, Other bat-
tery types
— Auxiliary battery (for example, for recuperation
or optional equipment) > page 232, 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 >