2015 MERCEDES-BENZ B-CLASS SPORTS check engine light

ProblemPossible causes/consequences andMSolutions
KEYLESS-GO is malfunctioning.
X Lock/unlock the vehicle using the remote control function of
the SmartKey.
X Have the vehicle and SmartKey checked at a qualified specialist
workshop.
If the vehicle can also not be locked/unlocked using the remote
control function: X Unlock ( Ypage 78) or lock ( Ypage 79) the vehicle using the
mechanical key.
X Have the vehicle and SmartKey checked at a qualified specialist
workshop.
The engine cannot be
started using the
SmartKey.The on-board voltage is too low.
X Switch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
X Check the starter battery and charge it if necessary (Y page 291).
or
X Jump-start the vehicle ( Ypage 293).
or
X Consult a qualified specialist workshop.
The engine cannot be
started using the Start/
Stop button. The
SmartKey is in the vehi-
cle.The vehicle is locked.
X Unlock the vehicle and try to start the vehicle again.
The SmartKey battery is discharged or nearly discharged.
X Check the SmartKey battery ( Ypage 73) and replace it if nec-
essary ( Ypage 74).
If this does not work:
X Start your vehicle with the SmartKey in the ignition lock.
There is interference from a powerful source of radio waves.
X Start your vehicle with the SmartKey in the ignition lock.
76SmartKey
Opening and closing

Useful information
iThis Operator's Manual describes all
models and all standard and optional equip- ment of your vehicle available at the time of
publication of the Operator's Manual.
Country-specific differences are possible.
Please note that your vehicle may not be
equipped with all features described. This
also applies to safety-related systems and
functions.
iRead the information on qualified special-
ist workshops ( Ypage 24).
Correct driver's seat position
GWARNING
You could lose control of your vehicle if you do
the following while driving:
R adjust the driver's seat, head restraint,
steering wheel or mirrors
R fasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint, steer-
ing wheel and mirror and fasten your seat belt before starting the engine.
X Observe the safety guidelines on seat
adjustment ( Ypage 93).
X Make sure that seat =is adjusted prop-
erly.
Manual seat adjustment ( Ypage 94)
Electrical seat adjustment ( Ypage 94)
When adjusting the seat, make sure that:
R you are as far away from the driver's air
bag as possible
R you are sitting in a normal upright posi-tion
R you can fasten the seat belt properly
R you have moved the backrest to an
almost vertical position
R you have set the seat cushion angle so
that your thighs are gently supported
R you can depress the pedals properly
X Check whether the head restraint is adjus-
ted properly ( Ypage 94).
When doing so, make sure that you have
adjusted the head restraint so that the back of your head is supported at eye level by the
center of the head restraint.
X Observe the safety notes on steering col-
umn adjustment ( Ypage 97).
X Make sure that steering wheel :is adjus-
ted properly.
Adjusting the steering wheel ( Y page 97)
When adjusting the steering wheel, make
sure that:
R you can hold the steering wheel with your
arms slightly bent
R you can move your legs freely
R you can see all the displays in the instru-
ment cluster clearly
X Observe the safety guidelines for seat belts
( Y page 40).
X Check whether you have fastened seatbelt ;properly ( Ypage 42).
92Correct driver's seat position
Seats, steering wheel and mirrors

Problems with the seat heating
ProblemPossible causes/consequences andMSolutions
The seat heating has
switched off prema-
turely or cannot be
switched on.The on-board voltage is too low because too many electrical con-
sumers are switched on.
X Switch off electrical consumers that you do not need, such as
the rear window defroster or interior lighting.
Once the battery is sufficiently charged, the seat heating will
switch back on automatically.
Steering wheel
Important safety notes
GWARNING
You could lose control of your vehicle if you do
the following while driving:
R adjust the driver's seat, head restraint,
steering wheel or mirrors
R fasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint, steer-
ing wheel and mirror and fasten your seat belt before starting the engine.
GWARNING
Children could injure themselves if they
adjust the steering wheel. There is a risk ofinjury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Neverleave children unsupervised in the vehicle.
Adjusting the steering wheel
GWARNING
If the steering wheel is unlocked while the
vehicle is in motion, it could change position
unexpectedly. This could cause you to lose
control of the vehicle. There is a risk of anaccident.
Before starting off, make sure the steering
wheel is locked. Never unlock the steering
wheel while the vehicle is in motion.
:Release lever
;To adjust the steering wheel height
=To adjust the steering wheel position
(fore-and-aft adjustment)
X Push release lever :down completely.
The steering column is unlocked.
X Adjust the steering wheel to the desiredposition.
X Push release lever :up completely.
The steering column is locked.
X Check if the steering column is locked.
When doing so, try to push the steering
wheel up or down or try to move it in the
fore-and-aft direction.
Steering wheel97
Seats, steering wheel and mirrors
Z

ProblemPossible causes/consequences andMSolutions
The engine is not run-
ning smoothly and ismisfiring.There is a malfunction in the engine electronics or in a mechanical
component of the engine management system.
X Only depress the accelerator pedal slightly.
Otherwise, non-combusted fuel may get into the catalytic con-
verter and damage it.
X Have the cause rectified immediately at a qualified specialistworkshop.
The coolant tempera-
ture gauge shows a
value above 248 ‡
(120 †). The coolant
warning lamp may also
be on and a warning
tone may sound.The coolant level is too low. The coolant is too hot and the engine
is no longer being cooled sufficiently.
X Stop as soon as possible and allow the engine and the coolant to
cool down.
X Check the coolant level ( Ypage 273). Observe the warning
notes as you do so and add coolant if necessary.
Automatic transmission
Important safety notes
GWARNING
If the engine speed is above the idling speed
and you engage transmission position Dor R,
the vehicle could pull away suddenly. There is a risk of an accident.
When engaging transmission position Dor R,
always firmly depress the brake pedal and do not simultaneously accelerate.
GWARNING
The automatic transmission switches to neu-
tral position Nwhen you switch off the engine.
The vehicle may roll away. There is a risk of an
accident.
After switching off the engine, always switch
to parking position P. Prevent the parked vehi-
cle from rolling away by applying the parkingbrake.
Bear in mind that the power transmission
between the engine and the transmission is
interrupted when the engine is switched off. To prevent the vehicle from rolling away:
R when the engine is switched off and the
vehicle is stationary shift the automatic
transmission to park position Pand
R apply the electric parking brake
DIRECT SELECT lever
Overview of transmission positions
jPark position with parking lock
kReverse gear
iNeutral
hDrive
The DIRECT SELECT lever is on the right of the
steering column.
142Automatic transmission
Driving and parking

!Overfilling the fuel tank could damage the
fuel system.
!Take care not to spill any fuel on painted
surfaces. You could otherwise damage the
paintwork.
!Use a filter when refueling from a fuel can.
Otherwise, the fuel lines and/or injection
system could be blocked by particles from
the fuel can.
Do not get into the vehicle again during the
refueling process. Otherwise, electrostatic
charge could build up again.
If you overfill the fuel tank, fuel could spray
out when the fuel pump nozzle is removed.
For further information on fuel and fuel quality ( Y page 335).
Refueling
General information
The fuel filler flap is unlocked or locked auto- matically when you unlock or lock the vehicle
with the key.
The position of the fuel filler cap is displayed æ in the instrument cluster. The arrow on
the filling pump indicates the side of the vehi-
cle.
Opening the fuel filler flap
:To open the fuel filler flap
;Tire pressure table
=To insert the fuel filler cap
?Instruction label for fuel type to be refu- eled
X Vehicles without KEYLESS-GO: remove
the SmartKey from the ignition lock.
X Vehicles with KEYLESS-GO start-func-
tion or KEYLESS-GO: open the driver's
door.
The on-board electronics now have status0 . This is the same as the SmartKey having
been removed.
X Press the fuel filler flap in the direction ofarrow :.
The fuel filler flap swings up.
X Turn the fuel filler cap counterclockwise
and remove it.
X Insert the fuel filler cap into the holder on
the inside of fuel filler flap =.
X Completely insert the filler neck of the fuel
pump nozzle into the tank, hook in place
and refuel.
X Only fill the tank until the pump nozzle
switches off.
Do not add any more fuel after the pump
stops filling for the first time. Otherwise, fuel
may leak out.
Closing the fuel filler flap
X Replace the cap on the filler neck and turn
clockwise until it engages audibly.
X Close the fuel filler flap.
Close the fuel filler flap before locking the vehicle.
If you are driving with the fuel filler cap open, the 8 reserve fuel warning lamp flashes. A
message appears in the multifunction display
( Y page 225).
In addition, the ;Check Engine warning
lamp may light up ( Ypage 244).
For further information on warning and indi-
cator lamps in the instrument cluster, see( Y page 244).
Refueling151
Driving and parking
Z

Heavy and light loads
GWARNING
If you rest your foot on the brake pedal while
driving, the braking system can overheat. Thisincreases the stopping distance and can even
cause the braking system to fail. There is a
risk of an accident.
Never use the brake pedal as a footrest. Never
depress the brake pedal and the accelerator
pedal at the same time.
!Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
If the brakes have been subjected to a heavy load, do not stop the vehicle immediately.
Drive on for a short while. This allows the air-
flow to cool the brakes more quickly.
Wet roads
If you have driven for a long time in heavy rain
without braking, there may be a delayed reac- tion from the brakes when braking for the firsttime. This may also occur after the vehicle has
been washed or driven through deep water.
You have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the vehi-
cle washed, brake firmly while paying atten-
tion to the traffic conditions. This will warm up
the brake discs, thereby drying them more
quickly and protecting them against corro-sion.
Limited braking performance on salt-
treated roads
If you drive on salted roads, a layer of salt
residue may form on the brake discs and
brake pads. This can result in a significantly
longer braking distance. R
In order to prevent any salt build-up, apply
the brakes occasionally while paying atten-
tion to the traffic conditions.
R Carefully depress the brake pedal and the
beginning and end of a journey.
R Maintain a greater distance to the vehicle
ahead.
Servicing the brakes
!If the red brake warning lamp lights up in
the instrument cluster and you hear a warn- ing tone while the engine is running, the
brake fluid level may be too low. Observe
additional warning messages in the multi-
function display.
The brake fluid level may be too low due tobrake pad wear or leaking brake lines.
Have the brake system checked immedi-
ately. This work should be carried out at a
qualified specialist workshop.
!A function or performance test should
only be carried out on a 2-axle dynamom-
eter. If you are planning to have the vehicle tested on such a dynamometer, contact an
authorized Mercedes-Benz Center to
obtain further information first. Otherwise,
you could damage the drive train or the
brake system.
!As the ESP ®
system operates automati-
cally, the engine and the ignition must be
switched off (the SmartKey must be in posi-
tion 0or 1in the ignition lock) if:
R the electric parking brake is tested on a
brake dynamometer (for a maximum of
ten seconds)
R the vehicle is towed with the front axle
raised.
Braking triggered automatically by ESP ®
may seriously damage the brake system.
All checks and maintenance work on the
brake system must be carried out at a quali-
fied specialist workshop. Consult a qualified
specialist workshop to arrange this.
158Driving tips
Driving and parking

Useful information
iThis Operator's Manual describes all
models and all standard and optional equip- ment of your vehicle available at the time of
publication of the Operator's Manual.
Country-specific differences are possible.
Please note that your vehicle may not be
equipped with all features described. This
also applies to safety-related systems and
functions.
iRead the information on qualified special-
ist workshops ( Ypage 24).
Important safety notes
GWARNING
If you operate information systems and com-
munication equipment integrated in the vehi-
cle while driving, you will be distracted from
traffic conditions. You could also lose controlof the vehicle. There is a risk of an accident.
Only operate the equipment when the traffic
situation permits. If you are not sure that this
is possible, park the vehicle paying attention
to traffic conditions and operate the equip-
ment when the vehicle is stationary.
You must observe the legal requirements for
the country in which you are currently driving when operating the on-board computer.
GWARNING
If the instrument cluster has failed or mal-
functioned, you may not recognize function
restrictions in systems relevant to safety. The operating safety of your vehicle may be
impaired. There is a risk of an accident.
Drive on carefully. Have the vehicle checked
at a qualified specialist workshop immedi-ately.
The on-board computer only shows messages
or warnings from certain systems in the mul- tifunction display. You should therefore make sure your vehicle is operating safely at all
times.
If the operating safety of your vehicle is
impaired, pull over as soon as it is safe to do
so. Contact a qualified specialist workshop.
For an overview, see the instrument panel
illustration (
Ypage 29).
Displays and operation
Instrument cluster lighting
The light sensor in the instrument cluster
automatically controls the brightness of the
multifunction display. In daylight, the displays
in the instrument cluster are not illuminated.
The lighting in the instrument cluster, in the
displays and the controls in the vehicle inte-
rior can be adjusted using the brightness con- trol knob.
The brightness control knob is located on the
bottom left of the instrument cluster ( Y page 29).
X Turn the brightness control knob clockwise
or counter-clockwise.
If the light switch is set to Ã,T or
L , the brightness is dependent upon
the brightness of the ambient light.
Coolant temperature display
GWARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.
Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department.
!A display message is shown if the coolant
temperature is too high.
192Displays and operation
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
$(USA
only)
J(Canada
only)
Check Brake Fluid
Level
There is not enough brake fluid in the brake fluid reservoir.
A warning tone sounds. The $(USA only)/ J(Canada only)
warning lamps in the instrument cluster may also light up.
GWARNING
The braking effect 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 ( Ypage 152).
X Consult a qualified specialist workshop.
X Do not add brake fluid. This does not correct the malfunction.
#
Check Brake Pad
Wear
The brake pads/linings have reached their wear limit.
X Visit a qualified specialist workshop.
G
Inoperative
One or more main features of the mbrace system are malfunc-
tioning.
X Have the mbrace system checked immediately at a qualified
specialist workshop.
Collision PrevenZ
tion Assist Plus
Currently UnavailZ
able See OperaZ
tor's Manual
COLLISION PREVENTION ASSIST PLUS is temporarily not opera-
tional.
Possible causes are: 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 the system is outside the operating temperature range.
R the on-board voltage is too low.
When the causes stated above no longer apply, the display mes-
sage disappears.
COLLISION PREVENTION ASSIST PLUS 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 ( Ypage 152).
X Restart the engine.
214Display messages
On-board computer and displays