2011 MERCEDES-BENZ B-CLASS HATCHBACK warning light

Display messages Possible causes/consequences and
M Solutions
!
Turn on the igni‐
tion to release
the parking brake The red
!indicato rlamp is lit.
You attempted to release the electric parking brak ewhile the igni-
tion was switched off.
X Turn the key to position 1in the ignition lock. J
Check brake fluid
level There is insufficient brake fluid in the brake fluid reservoir.
In addition, the red
Jwarning lamp in the instrument cluster
lights up and a warning tone sounds.
G WARNING
The braking effect may be impaired.
There is a risk of 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 Engage the electric parking brake.
X Do not top up the brake fluid. Topping up will not remedy the
fault.
X Consult a qualified specialist workshop. #
Check brake 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. 212
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
6
Restraint
sys. mal‐
function Consult
workshop There is a malfunction in the SRS (Supplemental Restrain
tSys-
tem). The 6warning lamp also lights up in the instrumen tclus-
ter.
G WARNING
The airbags or belt tensioners may either be triggered uninten-
tionally or, in the even tofanaccident, may not be triggered at all.
There is an increased ris kofinjury.
X Visi taqualified specialist workshop.
For further information on occupant safety, see (Y page 38).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 tensioner smay either be triggered uninten-
tionally or, in the event of an accident, may no tbe triggered at all.
There is an increased risk of injury.
X Visit a qualified specialist workshop. 6
Rear left malfunc‐
tion Consult work‐
shop or
Rear right malfunction
Consult 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 at all.
There is an increased risk of injury.
X Visit a qualified specialist workshop. 214
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
6
Rear centre mal‐
function Consult
workshop SRS has malfunctioned at the rear centre. The
6warning lamp
also lights up in the instrumen tcluster.
G WARNING
The airbags or belt tensioners may either be triggered uninten-
tionally or, in the even tofanaccident, may not be triggered at all.
There is an increased ris kofinjury.
X Visi taqualified specialist workshop. 6
Left
windowbag mal‐
function Consult
workshop or
Right windowbag malfunc‐
tion Consult work‐
shop There is a malfunction in the left-hand and/or right-hand window-
bag. The
6warning lamp also lights up in the instrument clus-
ter.
G WARNING
The left-hand and/or right-hand windowbag may either be trig-
gered unintentionally or, in the event of an accident, may not be
triggered at all.
There is an increased risk of injury.
X Visit a qualified specialist workshop. Lights
i Display messages about LEDs:
This display message will only appear if all LEDs have failed. Display messages Possible causes/consequences and
M Solutions
b
Left cornering
light or
Right cor‐ nering light The left or right-hand cornering light is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 103).
or
X Visit a qualified specialist workshop. b
Left dipped beam
or
Right dipped beam The left or right-hand dipped-beam headlamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 103).
or
X Visit a qualified specialist workshop. Display messages
215On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
b
Reversing light The reversing lamp is faulty.
X
Chec kwhether you are permitted to replace the bulb yourself
(Y page 103).
or
X Visit a qualified specialist workshop. b
Left tail lamp
or
Right tail lamp The left or right-hand tail lamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 103).
or
X Visit a qualified specialist workshop. b
Left daytime driv‐
ing lamp
or
Right daytime driving lamp The left or right-hand daytime driving lamp is defective.
X
Check whether you are permitted to replace the bulb yourself
(Y page 103).
or
X Visit a qualified specialist workshop. b
Intell. Light Sys‐
tem inoperative The Intelligent Light System is faulty. The lights remain available
without the Intelligent Light System.
X
Visit a qualified specialist workshop. b
Malfunction See
Owner's Manual The exterior lighting is faulty.
X
Visit a qualified specialist workshop. b
Malfunction See
Owner's Manual The exterior lighting is faulty.
X
Visit a qualified specialist workshop. Vehicles with trailer tow hitch: a fuse may have blown.
X
Check the fuses (Y page 287).
X If necessary, replace the blown fuse. Observe the warning notes
as you do so.
If the display message continues to be displayed:
X Visit a qualified specialist workshop. b
AUTO
lights inoper‐
ative The light sensor is faulty.
X
Visit a qualified specialist workshop. 218
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
b
Switch off lights The lights are still switched on when you leave the vehicle. A
warning tone also sounds.
X Tur nthe light switch to Ã. Adaptive Main-beam
Assist inoperative Adaptive Highbeam Assist is faulty.
X
Visit a qualified specialist workshop. Adaptive Main-beam
Assist currently
unavailable See
Owner's Manual Adaptive Highbeam Assist is deactivated and temporarily inoper-
ative. 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 Cleant he windscreen.
If the system detects that the camera is fully operational again,
the Adaptive Main-beam Assist available again message
is displayed.
Adaptive Highbeam Assist is operational again. Engine
Display messages Possible causes/consequences and
M Solutions
+
Top
up coolant See
Owner's Manual The coolant level is too low.
!
Avoid making long journeys with too little coolant in the engine
cooling system. The engine will otherwise be damaged.
X Top up the coolant, observing the warning notes before doing
so (Y page 265).
X If the coolant needs topping up more often than usual, have the
engine coolant system checked at a qualified specialist work-
shop. ? The fan motor is faulty.
X
If the coolant temperature is less than 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving on
mountain roads and stop-start traffic. Display messages
219On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
Telephone No
service Your vehicle is outside the network provider's transmitter/
receiver range.
X
Wait until the mobile phone operational readiness symbol
appears in the multifunction display. ¥
Top
up washer fluid The washer fluid level in th
ewasher fluid reservoir has dropped
below the minimum.
X Top up the washe rfluid (Y page 265). Key
Displa
ymessages Possible causes/consequences and
M Solutions
+
Key does not
belong to vehicle You have put the wrong key in the ignitio
nlock.
X Use the correct key. +
Replace key The key needs to be replaced.
X Visit a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
Seat belts
Problem Possible causes/consequences and
M Solutions
ü
Only for certain coun-
tries: the red seat belt
warning lamp lights up
for six seconds after
the engine starts. The seat belt warning lamp reminds the driver and front passenger
to fasten their seat belts.
X Fasten your seat belt (Y page 44).ü
Only for certain coun-
tries: the red seat belt
warning lamp lights up
after the engine starts.
In addition, a warning
tone sounds for up to
six seconds.
The driver's seat belt is not fastened.
X
Fasten your seat belt (Y page 44).
The warning tone ceases. Warning and indicator lamps in the instrument cluster
231On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions
ü
The red seat belt warn-
ing lamp lights up after
the engine starts, as
soon as the driver's or
the front-passenger
door is closed. The driver or front passenger has not fastened their seat belt.
X
Fasten your seat belt (Y page 44).
The warning lamp goes out. There are objects on the front-passenger seat.
X
Remove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out. ü
The red seat belt warn-
ing lamp flashes and an
intermittenta udible
warning sounds. The driver or fron
tpassenger has no tfastened their seat belt .At
the same time, you are driving faste rthan 25 km/h or have briefly
driven faster than 25 km/h.
X Fasten your seat belt (Y page 44).
The warning lamp goes out and the intermittent warning tone
ceases. There are objects on the front-passenger seat. At the same time,
you are driving faster than 25 km/h or have briefly driven faster
than 25 km/h.
X
Remove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out and the intermittent warning tone
ceases. 232
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Safety systems
Problem Possible causes/consequences and
M Solutions
J
The red brake system
warning lamp comes on
while the engine is run-
ning. A warning tone
also sounds. There is insufficient brake fluid in the brake fluid reservoir.
G WARNING
The braking effect may be impaired.
There is a risk of 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 Engage the electric parking brake.
X Do not top up the brake fluid. Topping up will not remedy 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.
For this reason, BAS (Brake Assist), BAS PLUS, ESP ®
(Electronic
Stability Program), PRE-SAFE ®
, the HOLD function, hill start assist,
the adaptive brake lights and ESP ®
trailer stabilisation are also
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.
This limits the steerability of the vehicle when braking and may
increase the braking distance.
If ESP ®
is deactivated or not operational, the vehicle's stability
during standard driving manoeuvres is reduced.
There is a risk of 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 not be available. Warning and indicator lamps in the instrument cluster
233On-board computer and displays Z