2021 MERCEDES-BENZ A-CLASS SALOON ECU

Yo
u can use TIREFIT tyre sealant toseal per fora-
tion damage of up to4 mm, particular lythose in
th e tyre contact sur face. You can use TIREFIT in
outside temp eratures down to-20°C. &
W
W ARNING
ARNING Risk of accident when using
tyre sealant
The tyre sealant may be unable toseal the
tyre proper ly, especially in thefo llowing cases:
R there are lar gecuts or punctures in the
tyre (la rger than damage pr eviously men-
tioned)
R the wheel rims ha vebeen damaged
R aTer journe yswith very low tyre pressure
or with 0at tyres #
Do not continue driving. #
Consult a quali/ed specialist workshop. &
W
W ARNING
ARNING Risk of injury and poisoning
from tyre sealant
Ty re sealant is hazardous tohealth and causes
ir rita tion. Do not allow it tocome into contact with
your skin, eyes or clo thing, and do not
swallow it. Do not inhale any vapours. Keep
th e tyre sealant away from children.
Obser vethefo llowing if you come into contact
with the tyre sealant: #
Rinse o. the tyre sealant from your skin
using water immediatel y. #
If tyre sealant gets into your eyes, thor-
oughly rinse them using clean water
immediatel y. #
If tyre sealant has been swallo wed,thor-
oughly rinse out your mouth immediately
and drink plenty of water. Do not induce
vo miting and seek medical attention
immediatel y. #
Change out of clo thing which has come
into contact with tyre sealant immedi-
atel y. #
If an alle rgic reaction occurs, seek medi-
cal attention immediatel y. *
N NO
OTE
TE Overheating due tothe tyre in0ation
compressor running too long #
Do not runth e tyre in0ation compressor
fo r longer than ten minutes without inter-
ru ption. Comply with
the manufacturer's saf ety no tes on
th e stic ker on the tyre sealant bottle.
Ha ve the tyre sealant bottle replaced in a quali/ed
specialist workshop every /ve years. #
Do not remo veany fore ign objects which ha ve
entered the tyre. Breakdown assistance
345
345

R
Keep awa y from /re and naked 0ames.
R Do not lean overth e batter y.
Obser vethe additional following points when
ch arging the batter y:
R Only use battery charge rs tested and
appro vedfo r Mercedes-Benz.
R Read the battery charge r's operating inst ruc-
tions before charging the batter y.
Obser vethe additional following points during
starting assistance:
R For starting assistance, only use batteries with
a nominal voltage of 12 V.
R The vehicles must not touch.
R P
P e
etr
tr ol engine:
ol engine: only accept starting assistance
if th e engine and exhaust system are cold. S
S
t
tar
ar ting assist
ting assist ance and c
ance and c har
harging t
ging t he 12 V batt
he 12 V batt ery
ery R
R
eq
eq uir
uir ements:
ements:
Plug-in h
Plug-in h ybr
ybrid:
id:in order tostart, theve hicle
re qu ires a su1cient charge leve l of the high-volt- age battery as
well as a su1cient po wer output of
th e 12 V on-board electrical system.
R The vehicle is secured with the electric par k-
ing brake.
R A
A ut
ut omatic tr
omatic tr ansmission:
ansmission: the transmission is in
position j.
R Manual tr
Manual tr ansmission:
ansmission: the transmission is in
neutral.
R The vehicle and all elect rical consume rsare
switched o..
R The bonnet is open. #
Slide co ver1 of positive clamp 2onthe
jump-starting connection point in the direction
of the ar row. #
Connect positive clamp 2onyour vehicle to
th e positive pole of the donor battery using
th e jump lead/charging cable. Alw ays begin
with positive clamp 2onyour ow nve hicle
/rst. 352
352
Breakdown assis
tance

#
V
Vehicles wit
ehicles wit h aut
h automatic tr
omatic tr ansmission:
ansmission: shiTthe
automatic transmission toposition i.
% V
V ehicles wit
ehicles wit h aut
h automatic tr
omatic tr ansmission:
ansmission: the
automatic transmission may be loc ked in posi-
tion jintheev ent of damage tothe electri-
cal system. ToshiT toi , pr ovide the on-
board electrical system with po wer
( / page 352). #
V
Vehicles wit
ehicles wit h manual tr
h manual tr ansmission:
ansmission: shiTto
neutral. #
Load theve hicle onto the transpor ter. #
V
Vehicles wit
ehicles wit h aut
h automatic tr
omatic tr ansmission:
ansmission: shiTthe
automatic transmission toposition j. #
V
Vehicles wit
ehicles wit h manual tr
h manual tr ansmission:
ansmission: engage
/rst or reve rsege ar. #
Use the electric parking brake tosecure the
ve hicle against rolling away. #
Only secure theve hicle bythe wheels. V V
ehicles wit ehicles wit h adap
h adaptiv
tive dam
e dam ping adjus
ping adjustment tment &
W
WARNING
ARNING Risk of an accident when trans-
porting vehicles with adaptive damping
adjustment
When transpo rting vehicles with adaptive
damping adjustment, theve hicle/trailer com-
bination may begin torock and start toskid. #
Load theve hicle cor rectly onto the
transpor ter. #
Secure theve hicle on all four wheels
with suitable tensioning straps. #
Do not exceed the maximum permissible
speed of 60 km/h when transporting. *
N
NOOTE
TE Damage totheve hicle from secur-
ing it inco rrectly #
ATer loading, theve hicle must be
secured on all four wheels. Otherwise,
th eve hicle could be damaged. #
A minimum dis tance of 20 cm upwards
and 10 cm down wards must be kept to
th e transport platform. #
Secure theve hicle on all four wheels aTer
loading.
4MA
4MA TIC v
TIC v ehicles/v
ehicles/v ehicles wit
ehicles wit h aut
h automatic tr
omatic tr ans-
ans-
mission
mission #
Make sure that the front and rear axles come
to rest on the same transpor tation vehicle.
* N
NOOTE
TE Damage tothe drive train due to
incor rect positioning of theve hicle #
Do not position theve hicle abo vethe
connection point of the transport vehi-
cle. 358
358
Breakdown assis
tance

#
Tow- start theve hicle while the clutch pedal is
fully depressed. #
Slowly re leasethe clutch pedal. #
Immediately shiT toneutral if the engine
starts. #
Stop theve hicle in accordance with the tra1c
conditions. #
Remo vetheto w bar. #
Remo vetheto wing eye. #
Have theve hicle checked at a quali/ed spe-
cialist workshop. Electr
Electr
ical fuses
ical fuses N
No
ot
tes on electr
es on electr ical fuses
ical fuses &
W
WARNING
ARNING Risk of accident and injury due
to ove rloaded lines
If yo u manipulate or bridge a faulty fuse or if
yo ure place it with a fuse with a higher amper-
age, the electric line could be overloaded.
This could result in a /re. #
Alwaysre place faulty fuses with speci-
/ed new fuses containing the cor rect
amperage. *
N
NOOTE
TE Damage due toincor rect fuses Electrical components or systems may be
damaged
byincor rect fuses, or their function-
ality may be signi/cantly impaired. #
Only use fuses that ha vebeen appr oved
by Mercedes-Benz and which ha vethe
cor rect fuse rating. Blown fuses must be
replaced with fuses of the
same rating, whi chyou can recognise bythe col-
our and the label. The fuse ratings and fur ther
information tobe obser ved can be found in the
fuse assignment dia gram.
F F use assignment diagr
use assignment diagr am:
am:onthe fuse box in the
engine compartment (/ page 361). *
N
NOOTE
TE Damage or malfunctions caused by
moisture Moisture may cause damage
tothe electrical
system or cause it tomalfunction. #
When the fuse box is open, make sure
th at no moisture can enter the fuse box. #
When closing the fuse box, make sure
th at the seal of the lid is positioned cor-
re ctly on the fuse box. If
th e ne wlyinser ted fuse also blo ws, ha vethe
cause traced and recti/ed at a quali/ed specialist
wo rkshop.
Ensure thefo llowing before replacing a fuse:
R The vehicle is secured against rolling away.
R All electrical consume rsare switched o..
R The vehicle is switched o..
The elect rical fuses are located in various fuse
bo xes:
R Fuse box in the engine compartment on the
leT-hand side of theve hicle, when vie wed in
th e direction of tr avel (/ page 361) 360
360
Breakdown assistance

shop. The new wheel must ha
vethe cor-
re ct dimensions. %
The emer gency spa rewheel is secured in the
emer gency spa rewheel bag in the boot.
Obser vethefo llowing no tes on removing an emer-
ge ncy spa rewheel:
R Before st owing the emer gency spa rewheel,
make sure there is no air leT in the tyre.
If necessar y,allow the air toescape.
R T
T o r
o r elease air fr
elease air fr om t
om the tyr
he tyr e:
e:remo vetheva lve
cap of the tyre.
R Press down the me tal insert in theva lve using
a pointed object, e.g. a pen.
R Screw theva lve cap onto theva lve.
Obser vethefo llowing no tes on /tting an emer-
ge ncy spa rewheel:
R The maximum permissible speed with an
emer gency spa rewheel /tted is 80 km/h.
R Do not /t the emer gency spa rewheel with
snow chains. R
Replace the emer gency spa rewheel aTer six
ye ars at the latest, rega rdless of wear.
R Check the tyre pressure of the emer gency
spa rewheel /tted. Cor rect the pressure as
necessar y.
% The speci/ed tyre pressure is stated on the
label of the emer gency spa rewheel.
% V
V ehicles wit
ehicles wit h a tyr
h a tyre pr
e pressur
essur e loss w
e loss w ar
arning
ning
syst
syst em:
em: if an emer gency spa rewheel is /tted,
th e tyre pressure loss warning system cannot
function reliabl y.Only restart the system
again when the emer gency spa rewheel has
been replaced with a new wheel.
V
V ehicles wit
ehicles wit h a tyr
h a tyre pr
e pressur
essur e monit
e monit or
oring sy
ing sy s-
s-
t
t em:
em: if an emer gency spa rewheel is /tted, the
tyre pressure monitoring system cannot func-
tion reliabl y.Fo r a few minutes aTer an emer-
ge ncy spa rewheel is /tted, the system may
still display the tyre pressure of there mo ved
wheel. Only restart the system again when the
emer gency spa rewheel has been replaced
with a new wheel. Be sure
toalso obser vethefo llowing fur ther rela-
te d subjects:
R Notes on tyre pressure (/ page 364)
R Tyre pressure table (/ page 365)
R Notes on /tting tyres (/ page 368)
R Fitting an emer gency spa rewheel
(/ page 373) In0ating In0ating
t
the emerg
he emerg ency spar
ency spar e wheel
e wheel *
N
NOOTE
TE Overheating due tothe tyre in0ation
compressor running too long #
Do not runth e tyre in0ation compressor
fo r longer than ten minutes without inter-
ru ption. R
R
eq
eq uir
uir ements:
ements:
Comply with the manufacturer's saf ety no tes on
th e stic ker of the emer gency spa rewheel and on
th e tyre in0ation compressor. #
Remo vethe stic ker with the label 80 km/h
from the tyre in0ation compressor housing Wheels and tyres
379
379

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions
Front-passenger airbag
enabled See Owner's Man-
ual *T
he front passen ger airbag will be enabled while theve hicle is in motion in thefo llowing situations:
R even when a child, a small adult or an object weighing less than the system weight thre shold is located on the front
passenger seat
R even when the front passenger seat is not occupied
The system may de tect objects or forc es that are adding tothewe ight applied tothe seat. &
W WARNING
ARNING Risk of injury or death when using a child restraint system while the front passenger airbag is ena-
bled
If yo u secure a child in a child restraint system on the front passenger seat and the front passenger airbag is ena-
bled, the front passenger airbag can deploy in theev ent of an accident.
The child could be struck bythe airbag. #
Ensure, bo thbefore and during the journe y,that the status of the front passenger airbag is cor rect.
NEVER use a rear wa rdfacing child restraint on a seat pro tected byan ACTIVE AIRBAG in front of it, DEATH or
SERIOUS INJURY tothe CHILD can occur. #
Stop theve hicle immediately in accordance with the tra1c conditions. #
Make sure that no objects are trapped under the front passenger seat. #
Check the status of automatic front passenger airbag actuation (/ page 57).#
If necessar y,consult a quali/ed specialist workshop immediatel y. Display messages and
warning/indicator lamps
405
405

V
V
ehicle
ehicle Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/conseq uences and
uences andM
MSolutions
Solutions
d
Vehicle is operational
Switch off ignition before
exiting *Y
ou are leaving theve hicle in a ready-to-drive state. #
Get out of theve hicle, secure it against rolling away and take theke y with you. #
Ifyo u do not lea vetheve hicle, switch o. the electrical consumers, e.g. the seat heating. Otherwise, the 12‑V bat-
te ry may dischar geand starting the engine may be possible only with the help of a second battery (jump start).
ï
Check trailer hitch
lock (white display message) *T
he trailer hitch is not operational during a jou rney with a trailer. &
W WARNING
ARNING Risk of an accident if the ball neck is not loc ked
The trailer may become de tach ed. #
Stop theve hicle immediately in accordance with the tra1c conditions. Do not continue driving. #
Uncouple the trailer and secure it against rolling away. #
Initiate a new swivelling procedu reand do not re-couple the trailer until the display message disappears. #
Initiate a new swivel mo vement (/ page 265). #
When the display message disappears, couple up the trailer and drive on.
If th e display message does not disappear, the trailer hitch is malfunctioning and the ball neck is not loc ked. Display messages and
warning/indicator lamps
421
421

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions #
Do not couple up the trailer. Drive on without the trailer. No tethere duced ground clearance due tothe unloc ked
ball nec k. #
Consult a quali/ed specialist workshop.
*W hen theve hicle is stationary with a coupled trailer, the trailer hitch is not operational. #
Uncouple the coupled trailer and secure it against rolling away. #
If t If the ball nec he ball nec k has been f
k has been f olded in:
olded in:unlockthe ball neck (/ page 265). #
Swivel the ball neck into the end position manually and let it engage. #
If t
If the ball nec
he ball nec k has been f
k has been f olded out
olded out::unlock the ball neck (/ page 265). #
Swivel the ball neck beneath the bumper manually and let it engage.
If th e display message does not disappear, the trailer hitch is malfunctioning and the ball neck is not loc ked. #
Do not couple up the trailer. Drive on without the trailer. No tethere duced ground clearance due tothe unloc ked
ball nec k. #
Consult a quali/ed specialist workshop.
Head-up display currently
unavailable See Owner's
Manual *T
he head-up displ ayistemp orarily una vailable. Possible causes:
R malfunctions in the po wer supply
R signal inter fere nce #
Stop in accordance with the tra1c conditions and switch theve hicle o. and on again. #
Ifth e display message still appears, consult a quali/ed specialist workshop. 422 422
Displ
aymessages and warning/indicator lamps