2021 MERCEDES-BENZ A-CLASS HATCHBACK ECU

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 271). #
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 271). #
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. 430 430
Displ
aymessages and warning/indicator lamps

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions #
Depress the brake pedal. #
Engage park position j. #
Consult a quali/ed specialist workshop.
Transmission Malfunction *The transmission is malfunctioning. The cause could be an overheated clutch or bloc kedge ars. #
Let the transmission cool down. #
Ifth e display message still appears following a restart, consult a quali/ed specialist workshop.
d Trans. oil overheated Drive
on with care *T
he transmission is overheating. When the display message is active, start-up and driving characteristics may be tem-
porarily impaired. #
Drive at low engine speed. #
Avoid sporty driving. #
Before pulling away on uphill gradients, let the transmission cool down until the display message disappears.
Parking lock inoperative
Apply the parking brake *T
he transmission is malfunctioning. The park position jcann otbe selected. #
Park theve hicle safel y. #
Use the electric parking brake tosecure theve hicle against rollingaway.
Teaching in transmission
Operate selector lever
Brake for XX seconds Risk
of vehicle rolling *T
he transmission is being taught in. There is a risk of theve hicle rolling away. #
Depress and hold the brake pedal until thete ach-in process has been comple ted.
The electric parking brake is applied automatically during thete ach-in process. #
Switch on theve hicle. 440 440
Displ
aymessages and warning/indicator lamps

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions #
Select park position j, transmission position kor neutral i.
Risk of vehicle rolling away
Apply parking brake See
Owner's Manual *T
he transmission position cann otbe reliably identi/ed. #
Use the electric parking brake tosecure theve hicle against rollingaway.
Teaching in transmission
complete *T
he transmission's teach-in process is comple te. All transmission positions can be selected again.
Transmission Malfunction
Visit workshop *T
he transmission is malfunctioning.
Consult a quali/ed specialist workshop.
Depress clutch fully to
start engine *Y
ou ha veattem pted tostart theve hicle without depressing the clutch pedal. #
Depress the clutch pedal and then start theve hicle.
*T hevehicle has stalled while theve hicle was pulling away,e.g. because the clutch pedal wasre leased tooqu ickl y. #
Depress the clutch pedal again.
The vehicle will start automaticall y. #
Slowly re leasethe clutch pedal topull away.
Clutch overheated Avoid
pulling away until the warn-
ing goes out *T
he clut chis under considerable load and is overheating.
Av oid frequent pulling away and driving at walking pace over longer distances. #
Stop theve hicle, paying attention toroad and tra1c conditions and lea vetheve hicle running.
The clutch will cool more quickly when theve hicle is running. Display messa
ges and warning/indicator lamps
441 441

Br
Br
ak
ak es
es Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/conseq uences and
uences andM
MSolutions
Solutions
!
Parking brake See Owner's
Manual *T
heyellow ! indicator lamp is lit. The electric parking brake is malfunctioning.
T
T o apply o apply :
: #
Switch theve hicle o. and switch it back on #
App lythe electric parking brake manually (/ page 217).
If it is not possible toapply the electric parking brake: #
Consult a quali/ed specialist workshop. #
Where necessar y,also secure the par kedve hicle against rolling away.
*T heyellow ! indicator lamp and there d! indicator lamp are lit. The electric parking brake is malfunctioning.
T
T o r
o r elease:
elease: #
Switch theve hicle o. and switch it back on #
Release the electric parking brake manually (/ page 217).
or #
Release the electric parking brake automatically (/ page 217).
If it is still not possible torelease the electric parking brake: #
Do not continue driving. Consult a quali/ed specialist workshop.
*T heyellow ! indicator lamp is lit and there d! indicator lamp is 0ashing. The electric parking brake is malfunc-
tioning. Display messages and
warning/indicator lamps
443
443

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions
The electric parking brake could not be applied or released. #
Switch theve hicle o. and switch it back on
T
T o apply
o apply :
: #
Release and then apply the electric parking brake manually (/ page 217).
T
T o r
o r elease:
elease: #
Apply and then release the electric parking brake manuall y.
If it is not possible toapply the electric parking brake or there d! indicator lamp continues to0ash: #
Do not continue driving. Consult a quali/ed specialist workshop. #
Where necessar y,also secure the par kedve hicle against rolling away.
*T heyellow ! indicator lamp is lit and there d! indicator lamp 0ashes for appr oximately ten seconds aTer the
electric parking brake has been applied or released. It then remains lit or goes out. The electric parking brake is mal-
functioning.
If t
If t he st he st at
ate of c
e of c harg
harge is t
e is t oo low
oo low :
: #
Char gethe 12 V batter y.
T
T o apply
o apply :
: #
Switch o. theve hicle.
The elect ric parking brake will be applied automatical ly.444
444
Display message
s andwarning/indicator lamps

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions
If yo u do not wantthe electric parking brake tobe applied, e.g. at an automatic car wash or when theve hicle is being
to we d, lea vetheve hicle switched on. This does not include having theve hicle towe d with there ar axle raised.
If th e electric parking brake is not applied automaticall y: #
Switch theve hicle o. and switch it back on #
Release and then apply the electric parking brake manually (/ page 217).
If it is still not possible toapply the electric parking brake: #
Consult a quali/ed specialist workshop. #
Where necessar y,also secure the par kedve hicle against rolling away.
T
T o r
o r elease:
elease: #
Ifth e conditions for automatic release are ful/lled and the electric parking brake is not released automaticall y,
re lease the electric parking brake manually (/ page 217).
If it is still not possible torelease the electric parking brake: #
Do not continue driving. Consult a quali/ed specialist workshop.
!
Release parking brake *T
hered! indicator lamp is 0ashing.
The electric parking brake is applied while you are driving:
R A condition for automatic release of the electric parking brake has not been ful/lled (/ page 217).
R You are per form ing emer gency braking using the electric parking brake (/ page 218). Display messages and
warning/indicator lamps
445
445

W
W
ar
ar ning/indicat
ning/indicat or lampP
or lam pP ossible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions
ï
Tr ailer tow hitch warning
lamp *T
hered trailer hitch warning lamp is lit.
The trailer hitch is not operational. &
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. #
Notethe messages on the instrument displa y.Engine
Engine
W
W
ar
ar ning/indicat
ning/indicat or lampP
or lam pP ossible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions
ÿ
Coolant warning lamp (red) *T
he red coolant warning lamp is lit while the engine is running.
Po ssible causes:
R The temp erature sensor is malfunctioning
R The coolant le vel is too low
R The air supply tothera diator is obstructed
R The radiator fan is faulty Display message
s andwarning/indicator lamps
481
481

Br
Br
ak
ak es
es
ABS (Anti-lo ckBraking System).............. 221
Ac tive Brake Assist................................. 241
Ad aptive brake lights.............................. 226
BAS (Brake Assist System).................... .222
Driving tips............................................ 169
EBD (Electronic Brake forc e Distribu-
tion).......................................................2 24
HOLD function....................................... 225
Limited braking e.ect (salt-treated
ro ads)................................................... .169
Ne w/replaced brake linings/brake
discs...................................................... 168
Po st-collision brak e.................................. 61
Ru nning-in no tes.................................... 168
Br
Br ak ak es
es
see Recuperation
Br Br aking assist aking assist ance
ance
see BAS (Brake Assist System)
Br
Br eakdo
eakdo wn
wn
Assistance overview. ................................ 20
To w- starting........................................... 364
To wing away.......................................... 360
Tr anspo rting theve hicle........................ .362
Wheel chang e........................................ 378 Br
Br ea kdo
eakdo wn
wn
see Flat tyre
Butt
Butt ons
ons
St eering wheel....................................... 279 C
C
Calls
Calls Mercedes me......................................... 311
Camera
Camera
Information............................................ 220
Camera
Camera
see 360° Camera
see Dashcam
see Reversing camera
Car key
Car key
see Key
Car w Car w ash
ash
see Care
Car w
Car w ash (car
ash (car e)
e)............................................ 337
Car
Car -t
-to-X
o-X -Communication
-Communication
Displaying hazard warnings.................... 305
Care
Care 360° camera......................................... 342 Air-water duct........................................ 337
Au
tomatic car wash.............................. .337
Carpet................................................... 343
Decorative foil........................................ 341
Display................................................... 343
Exterior lighting...................................... 342
Head-up display..................................... 343
High-pressure cleaner............................3 39
Pa int...................................................... 340
Plastic trim............................................3 43
Re alwo od/trim elements..................... .343
Re versing camera..................................3 42
Ro of lining............................................. 343
Seat belt................................................ 343
Seat co ver............................................. 343
Sensors................................................. 342
St eering wheel....................................... 343
Ta ilpipes................................................ 342
Tr ailer hitc h............................................ 342
Ve hicle soc ketfo rth e high-voltage
battery................................................... 342
Wa shing byhand.................................... 340
Wheels/rims.......................................... 342
Wi ndo ws................................................ 342
Wi per blades.......................................... 342 496 496
Index