2012 MERCEDES-BENZ A CLASS Owners Manual

Display messages Possible causes/consequences and
M SolutionsThe brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The
steerability and braking characteristics may be severely affec-
ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. ÷
currently unavail‐
able See Owner's
Manual ESP
®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist and
ESP ®
trailer stabilisation are temporarily unavailable.
The adaptive brake lights and COLLISION PREVENTION ASSIST
may also have failed.
In addition, the ÷ and å warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
The self-diagnosis function, for example, may not be complete.
G WARNING
The brake system continues to function normally, but without the
functions listed above.
The

braking distance may thus increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Carefully drive on a suitable stretch of road, making slight steer-
ing movements, at a speed above

20 km/h.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit a qualified specialist workshop. Display messages
231
On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions÷
inoperative See
Owner's Manual ESP
®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist and
ESP ®
trailer stabilisation are not available due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST
may also have failed.
In addition, the ÷ and å warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above.
The
braking distance may thus increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop. T!
÷
inoperative See
Owner's Manual EBD (electronic brake force distribution), ABS, ESP
®
, BAS, PRE-
SAFE ®
,

the HOLD function, hill start assist and ESP ®
trailer stabi-
lisation are unavailable due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST
may also have failed.
In addition, the ÷, å and ! warning lamps light up in
the instrument cluster and a warning tone sounds.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear wheels could therefore
lock, for example, if you brake hard.
The

steerability and braking characteristics may be severely affec-
ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately.232
Display messages
On-board computer and displays

Display messages Possible causes/consequences and
M Solutions!
Release parking
brake The red
! indicator lamp flashes and a warning tone sounds.
A condition for automatic release of the electric parking brake is
not fulfilled ( Y page 163).
You are driving with the electric parking brake applied.
X Release the electric parking brake manually. The red
! indicator lamp flashes and a warning tone sounds.
You are making an emergency stop using the electric parking
brake ( Y page 163). !
Parking brake See
Owner's Manual The yellow
! warning lamp lights up.
The electric parking brake is malfunctioning.
To apply:
X Switch the ignition off.
X Press the electric parking brake handle for at least ten seconds.
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Consult a qualified specialist workshop. The yellow
! warning lamp and the red ! indicator lamp
are lit.
The electric parking brake is malfunctioning.
To release:
X Switch off the ignition and turn it back on.
X Release the electric parking brake manually.
or
X Vehicles with manual transmission (automatic emergency
release): insert the seat belt in the belt buckle and accelerate
slightly more when pulling away.
X Vehicles with automatic transmission: release the electric
parking brake automatically

(Y page 163).
If the electric parking brake still cannot be released:
X Do not drive on.
X Consult a qualified specialist workshop. Display messages
233
On-board computer and displays Z

Display messages Possible causes/consequences and
M SolutionsThe red
! indicator lamp flashes and the yellow ! warning
lamp is lit.
The electric parking brake is malfunctioning.
To release:
X Switch off the ignition and turn it back on.
X Release the electric parking brake manually.
To apply:
X Switch off the ignition and turn it back on.
X Apply the electric parking brake manually.
If the red ! indicator lamp continues to flash:
X Do not drive on.
X Secure the vehicle against rolling away ( Y page 325).
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission:
shift the transmission
to P.
X Turn the front wheels towards the kerb.
X Consult a qualified specialist workshop. The yellow
! warning lamp lights up. The red ! indicator
lamp
flashes for about ten seconds after the electric parking brake
has been applied or released. It then goes out or remains lit.
The electric parking brake is malfunctioning.
X Switch off the ignition and turn it back on.
X Apply the electric parking brake.
If it is not possible to apply the electric parking brake:
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission:
shift the transmission
to P.
X Visit a qualified specialist workshop.
If it is not possible to release the electric parking brake:
X Vehicles with manual transmission (automatic emergency
release): insert the seat belt in the belt buckle and accelerate
slightly more when pulling away.
X Vehicles with automatic transmission: release the electric
parking brake automatically

(Y page 163).
If the electric parking brake still cannot be released:
X Consult a qualified specialist workshop.234
Display messages
On-board computer and displays

Display messages Possible causes/consequences and
M SolutionsThe yellow
! warning lamp lights up. If you manually apply or
release the electric parking brake, the red ! indicator lamp
flashes.
The electric parking brake is malfunctioning. It is not possible to
apply the electric parking brake manually.
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Visit a qualified specialist workshop. !
Parking

brake inop‐
erative The yellow
! warning lamp lights up. The red ! indicator
lamp flashes for about ten seconds after the electric parking brake
has been applied or released. It then goes out or remains lit.
The electric parking brake is malfunctioning, e.g. because of over-
voltage or undervoltage.
X Rectify the cause of the overvoltage or undervoltage, e.g. by
charging the battery or restarting the engine.
X Apply or release the electric parking brake.
If it remains impossible to apply or release the electric parking
brake:
X Switch off the ignition and turn it back on.
X Apply or release the electric parking brake.
If the electric parking brake still cannot be released:
X Consult a qualified specialist workshop. The display message is only shown while the vehicle is in motion.
The

red ! indicator lamp flashes and the yellow ! warning
lamp is lit.
It is not possible to apply the electric parking brake manually.
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission:
shift the transmission
to P.
X Visit a qualified specialist workshop. !
Turn on the igni‐
tion to release
the parking brake The red
! indicator lamp lights up.
You
attempted to release the electric parking brake while the igni-
tion was switched off.
X Turn the key to position 1 in the ignition lock. Display messages
235
On-board computer and displays Z

Display messages Possible causes/consequences and
M SolutionsJ
Brake immediately Vehicles with manual transmission: a malfunction has occurred
while the HOLD function was activated.
A
tone may also sound at regular intervals. If you attempt to lock
the vehicle, the tone becomes louder.
You cannot start the engine.
X Paying attention to the traffic situation, immediately depress the
brake pedal firmly and hold until the display message disap-
pears.
X Secure the vehicle against rolling away ( Y page 162).
You can restart the engine. J
Check brake fluid
level There is insufficient brake fluid in the brake fluid reservoir.
In

addition, the red J warning lamp lights up in the instrument
cluster and a warning tone sounds.
G WARNING
The braking efficiency may be impaired.
There is a risk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying
attention

to road and traffic conditions. Do not continue driving
under any circumstances.
X Secure the vehicle against rolling away ( Y page 162).
X Consult a qualified specialist workshop.
X Do not top up the brake fluid. This does not correct the fault. #
Check brake pad
wear The brake pads/linings have reached their wear limit.
X
Visit a qualified specialist workshop. PRE-SAFE
inoperative See
Owner's Manual
Important functions of PRE-SAFE
®

have failed. All other occupant
safety systems, e.g. airbags, remain available.
X Visit a qualified specialist workshop immediately.236
Display messages
On-board computer and displays

Display messages Possible causes/consequences and
M SolutionsPRE-SAFE
Functions cur‐
rently
limited See
Owner's Manual Adaptive Brake Assist is temporarily inoperative. Possible causes:
R
the radar sensor cover in the radiator trim is dirty.
R the function is impaired due to heavy rain or snow.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation.
R AMG vehicles: ESP ®
is deactivated.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
Once
the causes listed above no longer apply, the display message
goes out.
Adaptive Brake Assist is operational again.
If the display message does not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Y page 162).
X Clean the radar sensor cover in the radiator grille
(Y page 294).
X Restart the engine.
X AMG vehicles: reactivate ESP ®
(Y page 66). PRE-SAFE
Functions limited
See Owner's Manual Adaptive Brake Assist is faulty. The distance warning signal may
also have failed.
X
Visit a qualified specialist workshop. ü If the symbol appears in the multifunction display, a seat belt
tongue has been inserted into a rear seat belt buckle.
Further

information on the status indicator for the rear seat belts
(Y page 49). ý If the symbol appears in the multifunction display, a seat belt
tongue has not been inserted in a rear seat belt buckle.
G WARNING
A seat belt which is not worn correctly, or which has not been
engaged in the seat belt buckle correctly, cannot provide the
intended level of protection.
This poses an increased risk of injury.
X If necessary, ask the occupants in the rear to fasten their seat
belts ( Y page 47).
Further information on the status indicator for the rear seat belts
(Y page 49). Display messages
237
On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions6
Restraint
sys. mal‐
function Consult
workshop There is a malfunction in the SRS (Supplemental Restraint Sys-
tem).
The 6 warning lamp also lights up in the instrument clus-
ter.
G WARNING
The airbags or belt tensioners may either be triggered uninten-
tionally or, in the event of an accident, may not be triggered.
This poses an increased risk of injury.
X Visit a qualified specialist workshop.
Further information on occupant safety (Y page 40). 6
Front

left malfunc‐
tion Consult work‐
shop or Front
right malfunction
Consult workshop SRS has malfunctioned at the front on the left or right. The
6
warning lamp also lights up in the instrument cluster.
G WARNING
The airbags or belt tensioners may either be triggered uninten-
tionally or, in the event of an accident, may not be triggered.
This poses an increased risk of injury.
X Visit a qualified specialist workshop. 6
Rear left malfunc‐
tion Consult work‐
shop or Rear right
malfunction Con‐
sult workshop SRS has malfunctioned at the rear on the left or right. The
6
warning lamp also lights up in the instrument cluster.
G WARNING
The airbags or belt tensioners may either be triggered uninten-
tionally or, in the event of an accident, may not be triggered.
This poses an increased risk of injury.
X Visit a qualified specialist workshop.238
Display messages
On-board computer and displays