2021 AUDI A4 ECU

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 >

8W1012721BC
Emergency assistance

Emergency assistance
General information
> Park the vehicle as far as possible from moving
traffic in the event of a breakdown. In the event
of a flat tire, park the vehicle ona level surface.
If you are ona steep hill, be especially careful.
> Set the parking brake.
> Switch the emergency flashers on.
> Have the passengers exit the vehicle. They
should move to a safe place, for example be-
hind a guard rail.

Z\ WARNING
Follow the steps given above. This is for your
protection and the for the safety of others on
the road.

Equipment
Vehicle tool kit, tire mobility kit, and

vehicle jack
Applies to: vehicles with the vehicle tool kit, tire mobility kit,
and vehicle jack

Fig. 169 Luggage compartment: cargo floor cover
The vehicle tool kit, vehicle jack, tire mobility kit
and compressor are stored in the luggage com-
partment under the cargo floor cover.
> Applies to: sedan: To open the front compart-
ment, lift the cargo floor cover by the strap (@).
> Applies to: allroad: To open the front compart-
ment, pull the cargo floor cover by the plastic
handle @) slightly toward the rear. Lift the car-
go floor cover over the front compartment.
> To open the rear compartment, lift the cargo
floor cover by the plastic handle @).
> Applies to: sedan: Engage the plastic handle @)
in the luggage compartment seal.
> To remove the cargo floor cover completely,
pull it toward the rear at the plastic handle @).
> Applies to: vehicles with spare tire: Turn the
handle counter-clockwise and remove the spare
tire.
> Applies to: sedan: Unhook the cargo floor cover
again
before closing the luggage compartment
lid.
Depending on vehicle equipment, the vehicle tool
kit, tire mobility kit, and compressor may be lo-
cated under another cover that is secured with a
handwheel.
Applies to: vehicles with vehicle jack in the stor-
age bag: The bag with the vehicle jack is secured
to the tie-downs in the luggage compartment
and must be secured to the tie-downs again after
using it.

ZX WARNING
Applies to: vehicles with vehicle jack in the storage bag
A vehicle jack that is unsecured, incorrectly se-
cured, or not secured in the luggage compart-
ment may slide out of place when braking,
turning,
or in an accident, which increases the
risk of injuries to vehicle passengers. To re-
duce the risk of an accident, never transport
the vehicle jack without securing it.
G) Tips
—Insome vehicles, the rear compartment
may not open.
— The vehicle jack in your vehicle is mainte-
nance-free.

Tire mobility kit
Applies to: vehicles with tire mobility kit
> Read and follow the important safety precau-
tions > page 261.
> Set the parking brake.
> Select the “P” position.
> Check if a repair with the tire mobility kit is pos-
sible > page 262.
261

Emergency assistance

> Set the parking brake.
> Select the “P” position.
>» When towing a trailer: disconnect the trailer
from your vehicle.
> Lay out the vehicle tool kit > page 261 and the
spare tire > page 266.
>» Switch the ignition off.
> Turn the wheel bolt approximately one turn to
the left. To achieve the required torque, hold
the end of the wheel wrench*. If the wheel bolt
will not loosen, press carefully on the wheel
wrench* with your foot. Hold onto the vehicle
securely while doing this and make sure your
footing is stable.

ZA\ WARNING
The vehicle must also be secured to prevent it
from rolling when using the vehicle jack*. Use
suitable objects to block the front and back of
the wheel that is diagonal from the wheel
with the flat tire.


Removing the caps



@

=
(G)
me
as
Fig. 173 Wheel: wheel bolts with caps
?
> Slide the plastic clip from the vehicle tool kit
onto the cap until it engages > fig. 173.
> Remove the cap with the plastic clip.
Loosening the wheel bolts
©
i=
x © a


Fig. 174 Wheel: loosening the wheel bolts
> Slide the wheel wrench* from the vehicle tool
kit all the way onto the wheel bolt.
264

ZA WARNING
To reduce the risk of an accident, only loosen
the wheel bolts gently one turn before raising
the vehicle with the vehicle jack*.

Raising the vehicle
Applies to: vehicles with vehicle jack

© & Ss
g
= % oo


Fig. 176 Sill: positioning the vehicle jack
> Place the vehicle jack from the vehicle tool kit
ona firm surface. Use a flat, stable support if
necessary. Ona slippery surface such as tile,
you should use a non-slip pad such as a rubber
mat > A\.
> Find the marking on the sill that is closest to
the tire that will be changed > fig. 175. Behind
the marking, there is a lifting point on the side
sill for the vehicle jack.
> Turn the handwheel to raise the vehicle jack un-
der the lifting point on the side sill until the

8W1012721BC
Emergency assistance

bracket on the jack @) completely covers the
notch on the vehicle.
> Align the vehicle jack so the bracket (@) covers
the notch and the base (2) is flat on the ground.
The base @) must be directly under the mount-
ing point @.
> Mount the crank on the vehicle jack: insert the
crank into the opening on the handwheel. Turn
the crank to the left or right to secure it.
> Continue raising the vehicle jack with the crank
until the wheel lifts off the ground slightly.


ZA WARNING
—To reduce the risk of injury, make sure no
one is in the vehicle before raising it.
— Make sure the vehicle jack is stable. The risk
of injury is increased when the ground is
slippery or soft, because the vehicle jack
could slide or sink.
— Only raise your vehicle with the vehicle jack
provided by the factory. If you use a vehicle
jack designed for another vehicle, your vehi-
cle could slip and cause injury.
— Position the vehicle jack only at the desig-
nated mounting points on the side sill and
align the jack. Otherwise, the vehicle jack
could slip and cause an injury if it does not
have sufficient hold on the vehicle.
—To reduce the risk of injury, do not raise any
other vehicles or other loads using the vehi-
cle jack provided by the factory.
— To reduce the risk of an accident, never start
the
engine when the vehicle is raised.
—To reduce the risk of injury, no work should
be performed under the vehicle while it is
raised.

() Note
Do not lift the vehicle by the sill. Position the
vehicle jack only at the designated mounting
points on the side sill. Otherwise, your vehicle
could be damaged.
Removing and installing a wheel
| B8K-1479

Fig. 178 Wheel: alignment pin in the top hole
Removing a wheel
> Remove the top wheel bolt completely using
the hex socket in the screwdriver handle from
the vehicle tool kit > fig. 177 and place it ona
clean surface.
> Then install the alignment pin from the vehicle
tool kit in the empty wheel bolt hole by hand
> fig. 178.
> Remove the rest of the wheel bolts.
>» Remove the wheel >(). The alignment pin re-
mains in the hole while doing this.
Installing a wheel
Read the directions on > page 266 when instal-
ling unidirectional tires.
> Slide the wheel on over the alignment pin >@.
> Install the wheel bolts and tighten them gently
using the hex socket.
> Remove the alignment pin and tighten the re-
maining wheel bolt.
> Carefully lower the vehicle using the vehicle
jack*.
> Tighten the wheel bolts in a diagonal pattern
using the wheel wrench*.
265

Emergency assistance

The wheel bolts must be clean and loosen and
tighten easily. Check the contact surfaces for the
wheel and hub. Contaminants on these surfaces
must be removed before installing the wheel.

ZA\ WARNING
— Read and follow the important information
and notes under > page 242.
— Never use the hex socket in the screwdriver
handle or the hex socket wrench with the
ratchet to loosen or tighten the wheel bolts.
This increases the risk of an accident, be-
cause you will not be able to achieve the cor-
rect tightening specification.
@) Note
When removing or installing the wheel, the
rim
could hit the brake rotor and damage the
rotor. Work carefully and have a second per-
son help you.
Unidirectional tires
A unidirectional tire profile is identified by arrows
on the tire sidewall that point in the running di-
rection. You must always maintain the specified
running direction. This is necessary to ensure the
tire's optimal performance in regard to adhesion,
running noise, and friction, and to reduce the risk
of hydroplaning.

To benefit fully from the advantages of the uni-
directional tire design, you should replace faulty
tires as soon as possible and restore the correct
running direction on all of the tires.
> 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 83.
> Check the tire pressure on the installed wheel
as soon as possible.
> Correct the tire pressure and store it in the MMI
=> page 254.
266
> 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 261.
The tire pressure must be adjusted to a specified
value listed on the tire pressure sticker
=> page 245, fig. 168.
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
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 SO 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. >

8W1012721BC
Emergency assistance


— 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.
Collapsible spare tire
Applies to: vehicles with collapsible spare tire
The collapsible spare tire is intended for short-
term use only. Have the damaged tire checked
and replaced if necessary by an authorized Audi
dealer or authorized Audi Service Facility as soon
as possible.
There are some restrictions on the use of the col-
lapsible spare tire. The collapsible spare tire has
been designed specifically for your type of vehi-
cle. Do not replace it with the collapsible spare
tire from another type of vehicle.
The collapsible spare tire is located in the lug-
gage compartment under the cargo floor cover.
Requirement: the vehicle tool kit > page 261 and
the compressor must be laid out.
Removing
> Lift the cargo floor using the handle.
> Turn the handwheel counter-clockwise and re-
move it.
> Remove the collapsible spare tire.
You must inflate the collapsible spare tire before-
hand in order to use it.
Inflating
> Remove the valve cap from the collapsible
spare tire.
> Tighten the compressor hose on the collapsible
spare tire valve.
> Connect the compressor hose to a vehicle sock-
et and switch it on.
> Let the compressor run until the specified value
on the tire pressure sticker is reached
> page 245, fig. 168 > ©.
> Screw the valve cap back onto the valve.
Returning to storage
> To release air, turn the valve insert. See an au-
thorized Audi dealer or authorized Audi Service
Facility.
> Turn the valve insert back once the air has been
released.
>» Wait several hours before placing the collapsi-
ble spare tire in the spare wheel well. Only then
will it fold down completely so that you can
store it securely.
> Then screw the valve cap back onto the valve.
> Secure the collapsible spare tire with the hand-
wheel.
>» Fold the cargo floor cover back into place.
Snow chains
Using snow chains on the collapsible spare tire is
not permitted for technical reasons.
If you have to drive with snow chains and a front
tire fails, mount the collapsible spare tire in place
of a rear tire. Install the snow chains on the rear
tire that you removed, and install that in place of
the front tire that failed.

Z\ WARNING
— Only use the collapsible spare tire in emer-
gencies and drive very carefully, especially if
it is more than six years old.
— The compressor and the hose can become
very hot during operation which increases
the risk of burn injuries.
— After installing a collapsible spare tire, the
tire pressure must be checked as quickly as
possible to reduce the risk of an accident.
— Do not drive faster than 50 mph (80 km/h)
with the collapsible 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 collapsible spare
tire.
— Never drive using more than one collapsible
spare tire, because this increases the risk of
an accident.
— Normal tires or winter tires must not be
mounted on the collapsible spare tire rim.

267

Emergency assistance

Tow bar and towing cable
The vehicle can be towed with a tow bar or tow-
ing cable. Both drivers should be familiar with
the special considerations when towing, especial-
ly when using a towing cable.
Always make sure the traction force does not ex-
ceed the permitted level and there are no shock
loading conditions. There is always the risk of the
coupling becoming overloaded when driving off-
road.
For the most safety and security, drive with a tow
bar. You should use a towing cable only if a tow
bar is not available. Use a towing cable made of
synthetic elastic cable similar elastic material.

ZA\ WARNING
— Towing highly increases the risk of an acci-
dent, for example from colliding with the
towing vehicle.
— To reduce the risk of an accident, do not al-
low anyone to remain inside the vehicle
when it is being transported by a tow truck
or a special transporter.

@) Note
— If normal towing is not possible, for exam-
ple if the transmission is faulty or if the
towing distance is greater than 30 miles
(50 km), then transport the vehicle on a
special carrier.
— If the vehicle is towed by a tow truck at the
axle that is not permitted, this can cause se-
vere damage to the transmission.
— The vehicle must not be tow started for
technical reasons.
G) Tips
— If the power supply is interrupted, then it
will not be possible to move the selector
lever out of the "P" position. The parking
lock must be released using the emergency
release before towing the vehicle
=> page 100.
— Switch Audi pre sense* off > page 146 when
loading the vehicle onto a vehicle carrier,
train, ship,
or other type of transportation,
270
or when towing the vehicle. This can prevent
an undesired intervention from the pre
sense* system.
— Follow the local legal regulations for tow-
ing.
Read and follow the important information under
=> page 269.
Preparations
> Only secure the towing cable or tow bar at the
designated towing loop > page 271.
> Make sure the towing cable is not twisted. Oth-
erwise it could disconnect from the towing loop
while towing.
> Switch the emergency flashers on in both
vehicles > page 53. However, do not do this if it
prohibited by law.
Towing vehicle (front)
> Only start to drive when the towing cable is
taut.
> Press the brake pedal very carefully.
> Avoid sudden braking or driving maneuvers.
Vehicle being towed (rear)
» Make sure the ignition is switched on so that
the steering wheel is not locked and so that you
can use the turn signals, the horn, and the
windshield wipers if needed > A\.
> Switching it off before the vehicle has stopped
may impair the function of the brake booster
and power steering. You would then need to
use more force to steer and brake the vehicle.
> Release the parking brake > page 106.
> Select the “N” selector lever position.
> Make sure the towing cable is always taut.

ZA\ WARNING
— Never tow a vehicle using a tow bar or tow-
ing cable if the vehicle does not have electri-
cal power.
— If the vehicle runs out of power while it is
being towed, stop towing the vehicle imme-
diately and consult an authorized Audi deal-

er or qualified repair facility.

8W1012721BC
Emergency assistance

Rear towing loop


Fig. 181 Rear bumper: installing the towing loop
The threaded opening for the towing loop is lo-
cated on the right rear of the bumper.
> Remove the towing loop from the vehicle tool
kit > page 261.
> Press the cap inward with brief, strong pressure
> fig. 181. The cap will loosen from the bump-
er.
> Tighten the towing eye as far as it will go into
the mount. Use a suitable object to tighten the
towing eye completely and securely in the
mount.
>» After using, place the towing loop back in the
vehicle tool kit.


If the towing loop is not tightened until it
stops when installing, the threads may be
pulled out when towing the vehicle and result
in an accident.


Depending on the model, the shape of the cap
can vary.
271