2011 MERCEDES-BENZ B-CLASS HATCHBACK light

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

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, BAS PLUS, 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 deactivated.
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 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 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. 234
Warning and indicator lamps in the instrument clusterOn-board computer and displays

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,B
AS, BAS PLUS, 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 continue sto 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. 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, BAS PLUS,
EBD,P RE-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 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. Warning and indicator lamps in the instrument cluster
235On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions
÷
The yellow ESP
®
warn-
ing lamp flashes while
the vehicle is in motion. ESP
®
or traction control has intervened because there is a risk of
skidding or at least one wheel has started to spin.
Cruise control or DISTRONIC PLUS is deactivated.
X Only depress the accelerator pedal as far as necessary when
pulling away.
X Accelerate more gently while the vehicle is in motion.
X Adapt your driving style to suit the road and weather conditions.
X Do not deactivate ESP ®
.
For exceptions, see: (Y page 66).å
The yellow ESP
®
OFF
warning lamp is lit while
the engine is running. ESP
®
and ESP ®
trailer stabilisation are deactivated. ESP ®
will not
stabilise the vehicle if it starts to skid or if awheel starts to spin.
G WARNING
If ESP ®
is deactivated, the vehicle's stability during standard driv-
ing manoeuvres is reduced.
There is a risk of accident.
X Reactivate ESP ®
.
For exceptions, see: (Y page 66).
X Adapt your driving style to suit the road and weather conditions.
If ESP ®
cannot be activated:
X Have ESP ®
checked at a qualified specialist workshop. ֌
The yellow ESP
®
and
ESP ®
OFF warning
lamps are lit while the
engine is running. ESP
®
, BAS, BAS PLUS, PRE-SAFE ®
, the HOLD function, hill start
assist, the adaptive brake lights and ESP ®
trailer stabilisation are
not available due to a malfunction.
ATTENTION ASSIST is deactivated.
G WARNING
ESP ®
will not stabilise the vehicle if it starts to skid or if a wheel
starts to spin.
The brake system continues to function normally, but without the
functions listed above.
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. 236
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Problem Possible causes/consequences and
M Solutions
֌
The yellow ESP
®
and
ESP ®
OFF warning
lamps are lit while the
engine is running. ESP
®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist and
ESP ®
trailer stabilisation are temporarily not available.
The adaptive brake lights and BAS PLUS may also have failed.
ATTENTION ASSIST is deactivated.
G WARNING
ESP ®
will not stabilise the vehicle if it starts to skid or if a wheel
starts to spin.
Self-diagnosis is not yet complete.
The brake system continues to function normally, but without the
functions listed above.
If ESP ®
is deactivated or not operational, the vehicle's stability
during standard driving manoeuvres is reduced.
There is a risk of 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
237On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions
!
The red indicator lamp
for the electric parking
brake flashes and/or
the yellow warning
lamp for the electric
parking brake lights up.
The electric parking brake is temporarily malfunctioning or is
defective.
X
Observe the additional display messages in the multifunction
display. 6
The red SRS warning
lamp is lit while the
engine is running.
There is a malfunction in the SRS (Supplemental Restraint Sys-
tem).
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 Drive on carefully.
X Have SRS checked at a qualified specialist workshop immedi-
ately.
For further information on occupant safety, see (Y page 38).Engine
Problem Possible causes/consequences and
M Solutions
;
The yellow engine diag-
nostics warning lamp
lights up while the
engine is running. There may be a fault, for example:
R
in the engine management
R in the fuel injection system
R in the exhaust system
R in the ignition system (for vehicles with petrol engines)
R in the fuel system
The emission limit values may be exceeded and the engine may
be running in emergency mode.
X Have the vehicle checked as soon as possible at a qualified
specialist workshop. Vehicles with a diesel engine: the fuel tank has been run dry
(Y
page 143).
X Start the engine three to four times after refuelling.
If the yellow engine diagnostics warning lamp goes out, emer-
gency running mode is cancelled. The vehicle need not be
checked. 238
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Problem Possible causes/consequences and
M Solutions
æ
The yellow reserve fuel
warning lamp lights up
while the engine is run-
ning.
The fuel level has dropped into the reserve range.
X
Refuel at the nearest filling station. ?
The red coolant warn-
ing lamp lights up while
the engine is running
and the coolant tem-
perature gauge is at the
start of the scale.
The temperature sensor for the coolant temperature gauge is
faulty.
The coolant temperature is no longer being monitored. There is a
risk of engine damage if the coolant temperature is too high.
X
Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine. Do not continue driving
under any circumstances.
X Apply the parking brake.
X Consult a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
239On-board computer and displays Z

Problem Possible causes/consequences and
M Solutions
X
Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and top up the coolant (Y page 265).
Observe the warning notes as you do so.
X If you have to top up the coolant frequently, have the engine
cooling system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
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. Driving systems
Problem Possible causes/consequences and
M Solutions
·
The red distance warn-
ing lamp lights up while
the vehicle is in motion.
The distance to the vehicle in front is too small for the speed
selected.
X Increase the distance. ·
The red distance warn-
ing lamp lights up while
the vehicle is in motion.
Aw
arning tone also
sounds. You are approaching a vehicle or a stationary obstacle in your line
of travel at too high a speed.
X
Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to
brake or take evasive action. Warning and indicator lamps in the instrument cluster
241On-board computer and displays Z