2021 AUDI A6 check engine light

Checking and Filling

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.
The indicator light can also turn on if the fuel fill-
er cap is not closed correctly > page 2391).
Engine compartment
General information
Special care is required if you are working in the
engine compartment
For work in the engine compartment, such as
checking and filling fluids, there is a risk of in-
jury, scalding, accidents, and burns. For this
reason, follow all the warnings and general
safety precautions provided in the following in-
formation. The engine compartment is a dan-
gerous area in the vehicle. > A\.
Explanation of warnings (sticker in the engine
compartment):

Hot engine components!
@® Rotating parts!

The radiator fan can switch on at any
LS, time!

High voltage! Switch off the engine be-
5 fore coming into contact with any igni-
tion system components!




The catalytic converter can be damaged
"271 if the oil level is too high!

Always follow the instructions in the op-
erating manual.


)) Depending on the engine and country
242

ZA WARNING
— Turn the engine off.
— Switch the ignition off.
— Set the parking brake.
— Select the “P” (Park) selector lever position.
— Allow the engine to cool.
— Keep children away from the engine com-
partment.
— Never spill fluids on a hot engine. These flu-
ids (such as the freeze protection contained
in the coolant) can catch fire.
— Avoid short circuits in the electrical system.
— Never reach into the radiator fan. The fan is
temperature-controlled and can turn on
suddenly, even when the ignition is switched
off.
— 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.
— The cap on the coolant expansion tank must
never be opened when the coolant is hot.
The cooling system is under pressure. There
is a risk of burns
—To protect your face, hands, and arms from
hot steam or coolant, cover the cap with a
thick cloth when opening.
— Do not remove the engine cover under any
circumstances. This increases the risk of
burns.
— Due to the risk of electric shock, never touch
the ignition cable or other components in
the electronic high-voltage ignition system
when the engine is running or is starting.
— Ifa gear is engaged while the vehicle is sta-
tionary and the engine is running, do not
press the accelerator pedal inadvertently.
Pressing the accelerator pedal will cause the
vehicle to move, and this could result in an
accident.
— If inspections or repairs must be performed
while the engine is running, moving compo-
nents (such as the ribbed belt, generator,
and radiator fan) pose an additional risk.

Checking and Filling

Opening the hood
> With the door open, pull the lever <> below
the instrument panel in the direction of the ar-
row > fig. 158.
>» Raise the hood slightly > page 242.
> Press the lever > fig. 159 in the direction of the
arrow. This releases the hooks.
> Open the hood.
Closing the hood
> Push the hood down until you override the
force of the strut.
> Let the hood fall lightly into the latch. Do not
press it in. > AX.
Messages
B Warning! Hood is not locked. Stop vehicle
and check the lock
The hood latch is not locked correctly. Stop im-
mediately and close the hood.


AN 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
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.


D_ The & symbol is not available in all countries.
244

Checking and Filling

@ Tips
Audi recommends using engine oils provided
by Audi Genuine Parts.
Messages
Engine oil pressure
i Turn off engine. Oil pressure too low
Stop driving and switch the engine off. Check the
engine oil level > page 246.
— If the engine oil level is too low, add engine oil
=> page 247. 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.
Engine oil level
& Please add oil immediately.
Stop driving and switch the engine off. Check the
engine oil level > page 246 and add engine oil
immediately > page 247.
i Add max. x qt (x l) oil. You can continue
driving
Add the amount of oil shown immediately
=> page 247.
Reducing the oil level
3 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.
Engine oil sensor
BS 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
246
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.
3 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.
& 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.
Engine warm-up request
Tf 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.
@ Tips
The oil pressure warning = is not an oil level
indicator. Always check the oil level regularly.
Checking the engine oil level
The engine oil level can be checked in the MMI.
Observe the safety precautions > page 242, Gen-
eral information.
>» 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 247.

4K0012721BE
Checking and Filling

@) 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 |_| indi-
cator light. However, occasionally checking the
coolant level is recommended.
Messages
HAturn 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 250.
— If the coolant level is too low, add coolant
= page 250. 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
G12evo
Specification
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
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.
249

Checking and Filling

— 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.
ecking coolant

= Fe [RAZ-0540]

MIN


Fig. 162 Engine compartment - Coolant expansion tank:
@ cover with release button; @) markings
Observe the safety precautions > page 242, Gen-
eral information.
Checking the coolant level
> Park the vehicle on a level surface.
> Switch the ignition off.
> Open the hood > page 243.
The coolant expansion tank for some engines is
located in the water drip tray under a cover. Slide
the
cover that is located below the windshield
wiper on the front passenger's side toward the
windshield and remove the cover.
> Check the coolant level in the coolant expan-
sion tank > page 245, fig. 160 using the outer
markings @) > fig. 162. The coolant level must
be between the markings @) when the engine is
cold. When the engine is warm it can be slight-
ly above the upper marking.
>» When you add coolant to the expansion tank,
please refer to > page 249, Cooling system.
250
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. 162 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 mixed in the correct ratio
=> page 249 up to the MAX marking.
> Make sure that the fluid level remains stable.
Add more coolant if necessary.
> Turn the cap to the right to tighten it until you
feel resistance a second time.
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 242, 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.

4K0012721BE
Checking and Filling


— 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. 163 Engine compartment: cap on brake fluid reservoir
Observe the safety precautions > page 242, Gen-
eral information.
Checking the brake fluid level
> Slide the cover that is located below the wind-
shield wipers on the driver's side toward the
windshield and remove the cover.
> Read the brake fluid level on the brake fluid res-
ervoir > page 245, fig. 160. The brake fluid lev-
el must be between the MIN and MAX markings
ANG
The brake fluid level is monitored automatically.
Messages
EG 7 @ 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
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.
@) 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 z= / B or fl indicator light turns on,
there is a malfunction in the power supply, the
battery, or the vehicle electrical system.
= / B Electrical system: malfunction! Safely
stop vehicle
251

Checking and Filling

Do not continue driving and switch the ignition
off > A\. See an authorized Audi dealer or
authorized 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.
z= Electrical system: malfunction! Please con-
tact Service
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.

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
PE laa meee eee aCe)
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\.
252
Multiple batteries with different technologies
may be installed in your vehicle:
— Vehicle battery (for example, for starting the
engine, basic power supply) > page 253, 12
Volt vehicle battery or > page 253, Other bat-
tery types
— Auxiliary battery (for example, for recuperation
or optional equipment) > page 253, 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
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 254. 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.

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 >

Checking and Filling

an authorized Audi dealer or authorized Audi
Service Facility for more information.
ing the 12 Volt vehicle battery


Fig. 164 Engine compartment: connectors for a charger or
jump start cables
Observe the safety precautions > page 242, Gen-
eral information, > A\ in Battery general infor-
mation on page 252 and > /\.
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 243.
> Press the release lever on the positive terminal
and fold the cover upward © fig. 164.
> 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 243.

ZA WARNING
— Never connect a charging cable or jump
start cable directly to the 12 Volt vehicle

254

battery. Only use the connections in the en-
gine compartment > page 254.
— 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

B4M-0135}

Fig. 165 Engine compartment: washer fluid reservoir cap
Observe the safety precautions > page 242, Gen-
eral information.
The windshield washer reservoir <> contains the
cleaning solution for the windshield/rear window
and the headlight washer system* > fig. 165,
= page 245. The reservoir capacity can be found
in > page 314.
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 >