2012 MERCEDES-BENZ A CLASS brake light

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 Solutionsb
Left-hand tail
lamp/brake lamp
 or 
Right-hand tail
lamp/brake lamp The left or right-hand tail lamp/brake lamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 112).
or
X Visit a qualified specialist workshop. b
Left main beam or 
Right main beam The left or right-hand main-beam headlamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 112).
or
X Visit a qualified specialist workshop. b
Number plate lamp The left or right-hand licence plate lamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 112).
or
X Visit a qualified specialist workshop. b
Front
foglamp left  
or Front foglamp
right The left-hand or right-hand front foglamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 112).
or
X Visit a qualified specialist workshop. b
Rear fog lamp The rear foglamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 112).
or
X Visit a qualified specialist workshop. b
Front

left parking
lamp or Front
right parking lamp The front left or front right parking lamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 112).
or
X Visit a qualified specialist workshop. b
Reversing light The reversing lamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 112).
or
X Visit a qualified specialist workshop. Display messages
241
On-board computer and displays Z

Display messages Possible causes/consequences and
M SolutionsSpeed Limit Assist
Currently unavail‐
able See Owner's
Manual Speed Limit Assist is deactivated and temporarily inoperative.
Possible causes:
R
the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
X Clean the windscreen.
If the system detects that the camera is fully operational, the dis-
play message disappears.
Speed Limit Assist is operational again. Speed Limit Assist:
Unavailable in
this country Speed Limit Assist is only available in certain countries.
X
Drive on.
Speed
Limit Assist is available again as soon as you drive into a
country in which its use is approved. Speed Limit Assist
inoperative Speed Limit Assist is faulty.
X
Visit a qualified specialist workshop. ë
Off The HOLD function is deactivated. the vehicle is skidding.
A warning tone also sounds.
X
Reactivate the HOLD function later (Y page 179). The HOLD function is deactivated. When the brake pedal is firmly
depressed, an activation condition is not fulfilled.
A warning tone also sounds.
X
Check the activation conditions for the HOLD function
(Y page 179). Radar sensor deac‐
tivated See Own‐
er's Manual The radar sensor system is deactivated.
X
Check whether or not the radar sensor system may be activated
(Y page 350).
X Switch on the radar sensor system (Y page 223). Radar sensor deac‐
tivated

autom. See
Owner's Manual Vehicles with a navigation system: the vehicle is close to a radio
telescope
facility and is therefore prohibited from transmitting any
radar signals. The radar sensor system is deactivated automati-
cally.
If Blind Spot Assist was activated, it is no longer available. The
yellow 9 indicator lamps also light up in the exterior mirrors.
X Drive on.
Blind

Spot Assist is available again as soon as the vehicle is far
enough away from the radio telescope facility ( Y page 350).246
Display messages
On-board computer and displays

Safety systems
Problem Possible causes/consequences and
M SolutionsJ
The red brake system
warning
lamp is lit while
the engine is running. A
warning tone also
sounds. There is insufficient brake fluid in the brake fluid reservoir.
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 Do not top up the brake fluid. Topping up will not rectify the
fault.
X Consult a qualified specialist workshop.
X Observe the additional display messages in the multifunction
display. !
The

yellow ABS warning
lamp is lit while the
engine is running. ABS (Anti-lock Brake System) has been deactivated due to a fault.
BAS
(Brake Assist), COLLISION PREVENTION ASSIST, ESP ®
(Elec-
tronic Stability Program), PRE-SAFE ®
, the HOLD function, hill start
assist, the adaptive brake lights and ESP ®
trailer stabilisation are
also therefore deactivated, for example.
ATTENTION ASSIST is deactivated.
G WARNING
The 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 Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic trans-
mission, will be unavailable. 258
Warning and indicator lamps in the instrument cluster
On-board computer and displays

Problem Possible causes/consequences and
M Solutions!
The
yellow ABS warning
lamp is lit while the
engine is running. ABS is temporarily unavailable. Therefore, BAS, COLLISION PRE-
VENTION
ASSIST, ESP ®
, EBD (electronic brake force distribution),
PRE-SAFE ®
, the HOLD function, hill start assist, the adaptive brake
lights and ESP ®
trailer stabilisation, for example, are also deacti-
vated.
Possible causes:
R Self-diagnosis is not yet complete.
R the on-board voltage may be insufficient
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 a 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.
The functions mentioned above are available again when the
warning lamp goes out.
If the warning lamp is still on:
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
259
On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions!
The
yellow ABS warning
lamp is lit while the
engine is running. A
warning tone also
sounds. EBD is faulty. Therefore, ABS, BAS, COLLISION PREVENTION
ASSIST,
ESP®
, PRE-SAFE ®
, the HOLD function, hill start assist, the
adaptive brake lights and ESP ®
trailer stabilisation, for example,
are not available either.
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 Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. J֌!
The red brake warning
lamp, the yellow ESP
®
and ESP ®
OFF warning
lamps and the yellow
ABS warning lamp are
lit while the engine is
running. ABS and ESP
®
are malfunctioning. Therefore, BAS, COLLISION
PREVENTION ASSIST, EBD, PRE-SAFE ®
, the HOLD function, hill
start assist, the adaptive brake lights and ESP ®
trailer stabilisa-
tion, for example, are not available either.
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 Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop.260
Warning and indicator lamps in the instrument cluster
On-board computer and displays