2015 MERCEDES-BENZ C-Class SEDAN check engine light

X
To unlock the vehicle: touch the inner
surface of the door handle.
X To lock the vehicle: touch sensor sur-
face 0043or0044.
Make sure that you do not touch the inner
surface of the door handle.
X Convenience closing feature: touch
recessed sensor surface 0044for an exten-
ded period.
Further information on the convenience
closing feature (Y page 99).
X To unlock the trunk lid: pull the handle on
the trunk lid.
Deactivating If you do not intend to use the vehicle for a
longer period of time, you can deactivate KEY- LESS-GO. The SmartKey will then use very lit-
tle power, thereby conserving battery power.
For the purposes of activation/deactivation,
the vehicle must not be nearby.
X To deactivate: press the0037button on
the SmartKey twice in rapid succession.
The battery check lamp of the SmartKey
lights up twice briefly and KEYLESS-GO is
deactivated.
X To activate: press any button on the
SmartKey or insert the SmartKey into the
ignition lock.
KEYLESS-GO and all of its associated fea-
tures are available again. KEYLESS-GO start function
Bear in mind that the engine can be started by any of the vehicle occupants if there is a
SmartKey in the vehicle. Changing the settings of the locking
system
You can change the settings of the locking
system. This means that only the driver's door and the fuel filler flap are unlocked when the
vehicle is unlocked. This is useful if you fre-
quently travel on your own.
X To change the setting: press and hold
down the 0036and0037 buttons simulta-
neously for approximately six seconds until
the battery check lamp flashes twice
(Y page 84).
If the setting of the locking system is changed
within the signal range of the vehicle, press-
ing the 0037or0036 button:
R locks or
R unlocks the vehicle
The SmartKey now functions as follows:
X To unlock the driver's door: press the
0036 button once.
X To unlock centrally: press the0036but-
ton twice.
X To lock centrally: press the0037button.
The KEYLESS-GO function is changed as fol-
lows:
X To unlock the driver's door: touch the
inner surface of the door handle on the
driver's door.
X To unlock centrally: touch the inner sur-
face of the door handle on the front-
passenger door or the rear door.
X To lock centrally: touch the outer sensor
surface on one of the door handles.
X To restore the factory settings: press
and hold down the 0036and0037 buttons
simultaneously for approximately six sec- 82
SmartKeyOpening and closing

Problem
Possible causes/consequences and
0050
0050Solutions 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 347).
or
X Jump-start the vehicle (Y page 349).
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 (Y page 84) and replace it if nec-
essary (Y page 84).
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. You have lost a Smart-
Key. X
Have the SmartKey deactivated at a qualified specialist work-
shop.
X Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. You have lost the
mechanical key. X
Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. 86
SmartKeyOpening and closing

Useful information
i This 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.
i Read the information on qualified special-
ist workshops (Y page 26). Correct driver's seat position
G
WARNING
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 (Y page 109).
X Make sure that seat 0087is adjusted prop-
erly.
Electrical seat adjustment (Y page 110)
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 position
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.
R your legs are not fully extended
X Check whether the head restraint is adjus-
ted properly.
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 guidelines on steering
wheel adjustment (Y page 115).
X Make sure that steering wheel 0043is adjus-
ted properly.
Adjust the steering wheel manually
(Y page 115)
Adjust the steering wheel electrically
(Y page 116)
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 44).
X Check whether you have fastened seat
belt 0044properly (Y page 46).108
Correct driver's seat positionSeats, steering wheel and mirrors

Problems with the seat ventilation
Problem
Possible causes/consequences and
0050
0050Solutions The seat ventilation 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 ventilation can
be switched back on. Steering wheel
Important safety notes
G
WARNING
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. G
WARNING
Children could injure themselves if they
adjust the steering wheel. There is a risk of
injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never leave children unsupervised in the vehicle.
The electrically adjustable steering wheel can
still be adjusted when there is no key in the
ignition lock. Adjusting the steering wheel man-
ually
0043
Release lever
0044 To adjust the steering wheel height
0087 To adjust the steering wheel position
(fore-and-aft adjustment)
X Push release lever 0043down completely.
The steering column is unlocked.
X Adjust the steering wheel to the desired
position.
X Push release lever 0043up 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 wheel
115Seats, steering wheel and mirrors Z

Problems with the windshield wipers
Problem
Possible causes/consequences and
0050
0050Solutions The windshield wipers
are jammed. Leaves or snow, for example, may be obstructing the windshield
wiper movement. The wiper motor has been deactivated.
X For safety reasons, you should remove the SmartKey from the
ignition lock.
or X Switch off the engine using the Start/Stop button and open the
driver's door.
X Remove the cause of the obstruction.
X Switch the windshield wipers back on. The windshield wipers
fail completely. The windshield wiper drive is malfunctioning.
X Select another wiper speed on the combination switch.
X Have the windshield wipers checked at a qualified specialist
workshop. The windshield washer
fluid from the spray
nozzles no longer hits
the center of the wind-
shield. The spray nozzles are misaligned.
X Have the spray nozzles adjusted at a qualified specialist work-
shop. 136
Windshield wipersLights and windshield wipers

Starting the engine
Important safety notes G
WARNING
If children are left unsupervised in the vehicle, they could:
R open the doors, thus endangering other
people or road users.
R get out and disrupt traffic.
R operate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they:
R release the parking brake.
R shifting the automatic transmission out of
park position P
R Start the engine.
There is a risk of an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children or animals unattended in the
vehicle. Always keep the SmartKey out of
reach of children. G
WARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Inhaling
these exhaust gases leads to poisoning. There is a risk of fatal injury. Therefore never leave
the engine running in enclosed spaces with-
out sufficient ventilation. G
WARNING
Flammable materials introduced through
environmental influence or by animals can
ignite if in contact with the exhaust system or parts of the engine that heat up. There is a risk
of fire.
Carry out regular checks to make sure that
there are no flammable foreign materials in
the engine compartment or in the exhaust
system.
! Do not depress the accelerator when
starting the engine. General notes The catalytic converter is preheated for up to
30 seconds after a cold start. The sound of
the engine may change during this time.
Automatic transmission X
Shift the transmission to position P
(Y page 164).
The transmission position display in the
multifunction display shows
P (Y page 166).
You can also start the engine when the trans- mission is in position N.
Starting procedure with the SmartKey To start the engine using the SmartKey
instead of the Start/Stop button, pull the
Start/Stop button out of the ignition lock.
X Turn the SmartKey to position 3in the igni-
tion (Y page 157) lock and release it as
soon as the engine is running.
If the engine will not start: X Remove the SmartKey from the ignition
lock.
X Reinsert the SmartKey into the ignition lock
after a short waiting period.
X Turn the SmartKey to position 2in the igni-
tion lock (Y page 157).
The indicator lamps in the instrument clus- ter light up (Y page 284).
X Turn the SmartKey to position 3in the igni-
tion lock (Y page 157) and release it as
soon as the engine is running.
Starting procedure with the Start/Stop button The Start/Stop button is only available on
vehicles with KEYLESS-GO or the KEYLESS-
GO start function.
The Start/Stop button can be used to start
the vehicle manually without inserting the
SmartKey into the ignition lock. The Start/
Stop button must be inserted in the ignition Driving
159Driving and parking Z

Problems with the engine
Problem
Possible causes/consequences and
0050
0050Solutions The engine does not
start. The starter motor
can be heard. R
There is a malfunction in the engine electronics.
R There is a malfunction in the fuel supply.
X Before attempting to start the engine again, turn the SmartKey
in the ignition back to position 0or press the Start/Stop button
repeatedly until all indicator lamps in the instrument cluster go out.
X Try to start the engine again (Y page 159). Avoid excessively
long and frequent attempts to start the engine as these will drain
the battery.
If the engine does not start after several attempts:
X Consult a qualified specialist workshop. The engine does not
start. You cannot hear
the starter motor. The on-board voltage is too low because the battery is too weak or
discharged.
X Jump-start the vehicle (Y page 349).
If the engine does not start despite attempts to jump-start it:
X Consult a qualified specialist workshop. The starter motor was exposed to a thermal load that was too high.
X Try to start the engine again (Y page 159).
If the engine still does not start: X Consult a qualified specialist workshop. The engine is not run-
ning smoothly and is
misfiring. 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 specialist
workshop. The coolant tempera-
ture gauge shows a
value above 248 ‡
(120 †). 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 (Y page 327). Observe the warning
notes as you do so and add coolant if necessary. Driving
163Driving and parking Z

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 first time. 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 upthe 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 to brake 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 wish to operate the vehicle on
such a dynamometer, please consult an
authorized Mercedes-Benz Center in
advance. You could otherwise damage the
drive train or the brake system.
! The ESP ®
system operates automatically.
The engine and the ignition must therefore be switched off (the SmartKey must be in
position 0or 1in the ignition lock or the
Start/Stop button must be in position 0or
1) if the electric parking brake is tested on a brake dynamometer.
Braking triggered automatically by ESP ®
may cause severe damage to 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.
Have brake pads installed and brake fluid
replaced at a qualified specialist workshop.
If the brake system has only been subject to
moderate loads, you should test the function-
ality of your brakes at regular intervals.
Information on BAS (Brake Assist) (Y page 67)
and BAS PLUS (Brake Assist PLUS)
(Y page 67).
For safety reasons, Mercedes-Benz recom-
mends only installing the following brake
disks and brake pads/linings:
R brake disks that have been approved by
Mercedes-Benz
R brake pads/linings that have been
approved by Mercedes-Benz or that are of
an equivalent standard of quality
Other brake disks or brake pads/linings can
compromise the safety of your vehicle.
Always replace all brake disks and brake
pads/linings on an axle at the same time.
Always install new brake pads/linings when
replacing brake disks.
The vehicle is equipped with lightweight
brake disks to which the wheel assembly with rim and threaded connection is matched. Driving tips
181Driving and parking Z