engine MERCEDES-BENZ C-Class SEDAN 2015 W205 Repair Manual

R
you engage reverse gear R.
R you move the transmission out of position
P.
R you unfasten your seat belt or open the
driver's door.
R the vehicle starts to roll.
R the brake system requires this.
R the temperature in the vehicle interior devi-
ates from the set range.
R the system detects moisture on the wind-
shield when the air-conditioning system is
switched on.
R the battery's condition of charge is too low.
Shifting the transmission to position Pdoes
not start the engine.
Deactivating/activating the ECO start/
stop function X
To switch off: press ECO button 0043.
Indicator lamp 0044goes out.
X To switch on: press ECO button 0043.
Indicator lamp 0044lights up.
If indicator lamp 0044is off, the ECO start/stop
function has been deactivated manually or as the result of a malfunction. The engine will
then not be switched off automatically when
the vehicle stops.
Selecting drive program S+deactivates the
ECO start/stop function. If you press ECO
button 0043, the ECO start/stop function is
activated. 162
DrivingDriving and pa
rking

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

Automatic transmission
Important safety notes
G
WARNING
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. G
WARNING
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 parking
brake.
Bear in mind that the power transmission
between the engine and the transmission is
interrupted when the engine is switched off.
For this reason, shift the automatic transmis-
sion to Pwhen the engine is switched off and
the vehicle is at a standstill. Apply the electric parking brake to prevent the vehicle from roll-ing away. DIRECT SELECT lever
Overview of transmission positions 005D
Park position with parking lock
005E Reverse gear
005C Neutral
005B Drive
The DIRECT SELECT lever is on the right of the
steering column.
The DIRECT SELECT lever always returns to
its original position. The current transmission position P,R, Nor Dappears in the transmis-
sion position display in the multifunction dis- play (Y page 166).
Engaging park position P !
If the engine speed is too high or the vehi-
cle is moving, do not shift the automatic
transmission directly from Dto R, from Rto
D or directly to P. The automatic transmis-
sion could otherwise be damaged. 005D
Park position with parking lock
005E Reverse gear 164
Automatic trans
missionDriving and parking

005C
Neutral
005B Drive
X Push the DIRECT SELECT lever in the direc-
tion of arrow P.
Engaging park position P automatically Park position
Pis automatically engaged if:
R you switch off the engine using the Smart-
Key and remove the SmartKey.
R you switch off the engine using the Start/
Stop button and open the driver's door.
R you open the driver's door when the vehicle
is stationary or driving at very low speed
and the transmission is in position Dor R.
Engaging reverse gear R !
Only shift the automatic transmission to
R
when the vehicle is stationary.
X If the transmission is in position Dor N:
push the DIRECT SELECT lever up past the first point of resistance.
X If the transmission is in position P: depress
the brake pedal and push the DIRECT
SELECT lever up past the first point of
resistance.
The ECO start/stop function is not available
when reverse gear is engaged. Further infor-
mation on the ECO start/stop function
(Y page 161).
Shifting to neutral N 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.
X If the transmission is in position Dor R:
push the DIRECT SELECT lever up or down to the first point of resistance.
X If the transmission is in position P: depress
the brake pedal and push the DIRECT
SELECT lever up or down to the first point of
resistance.
If you switch the engine off with the trans-
mission in position Ror D, the automatic
transmission shifts to Nautomatically.
With the SmartKey: if you then open one of
the front doors or remove the SmartKey from
the ignition, the automatic transmission
shifts to P.
With the Start/Stop button: if you then
open one of the front doors, the automatic
transmission shifts to P.
If you want the automatic transmission to
remain in neutral N, e.g. when having the
vehicle cleaned in an automatic car wash with a towing system:
Using the SmartKey:
X Switch on the ignition.
X Depress the brake pedal and keep it
depressed.
X Shift to neutral N.
X Release the brake pedal.
X Release the electric parking brake.
X Switch off the ignition and leave the Smart-
Key in the ignition lock. Automatic transmission
165Driving and parking Z

With the Start/Stop button:
X Switch on the ignition.
X Depress the brake pedal and keep it
depressed.
X Pull the Start/Stop button out of the igni-
tion.
X Insert the SmartKey into the ignition lock.
X Shift to neutral N.
X Release the brake pedal.
X Release the electric parking brake.
X Switch off the ignition and leave the Smart-
Key in the ignition lock.
Engaging drive position D X
If the transmission is in position Ror N:
push the DIRECT SELECT lever down past
the first point of resistance.
X If the transmission is in position P: depress
the brake pedal and push the DIRECT
SELECT lever down past the first point of
resistance. Transmission position and drive pro-
gram display
! If the transmission position display in the
multifunction display is not working, you
should pull away carefully to check whether the desired transmission position is
engaged. Ideally, you should select trans-
mission position Dand drive program Eor
S. 0043
Status symbol drive program
0044 Transmission position
0087 Gear The current transmission position and drive
program appear in the multifunction display.
The arrows in the transmission position dis-
play show how and into which transmission
positions you can change using the DIRECT
SELECT lever. Transmission positions
0045 Park position
This prevents the vehicle from roll-
ing away when stopped.
Do not shift the transmission into
position P(Y page 164) unless the
vehicle is stationary. The parking
lock should not be used as a brake when parking. Always apply the
electronic parking brake in addi-
tion to the parking lock in order to
secure the vehicle.
The automatic transmission shifts
to Pautomatically if you:
R remove the SmartKey
R switch off the engine when in R
or Dand open one of the front
doors
If the vehicle electronics are mal-
functioning, the transmission may
be locked in position P. Have the
vehicle electronics checked imme- diately at a qualified specialist
workshop. 0046 Reverse gear
Only shift the transmission to
R
when the vehicle is stationary. 166
Automatic transmissionDriving and parking

0044 Neutral
Do not shift the transmission to
N
while driving. Otherwise, the auto-
matic transmission could be dam-
aged.
No power is transmitted from the
engine to the drive wheels.
Releasing the brakes will allow you
to move the vehicle freely, e.g. to
push it or tow it.
If ESP ®
is deactivated or faulty:
shift the transmission to position N
if the vehicle is in danger of skid-
ding, e.g. on icy roads.
If you switch off the engine using
the SmartKey or the Start/Stop
button, the automatic transmission shifts to neutral Nautomatically.
! Rolling in neutral
Ncan damage
the drive train. 003A Drive
The automatic transmission
changes gear automatically. All
forward gears are available.
Driving tips
Changing gear The automatic transmission shifts to the indi-
vidual gears automatically when it is in trans-
mission position D. This automatic gear shift-
ing behavior is determined by:
R the selected drive program (Y page 167)
R the position of the accelerator pedal
R the road speed
Accelerator pedal position Your style of driving influences how the auto-
matic transmission shifts gear:
R little throttle: early upshifts
R more throttle: late upshifts Double-clutch function When shifting down, the double-clutch func-
tion is active regardless of the currently selec-
ted drive program. The double-clutch functionreduces load change reactions and is condu-cive to a sporty driving style. The sound gen-
erated by the double-clutch function depends
on the drive program selected.
Kickdown Use kickdown for maximum acceleration.
X Depress the accelerator pedal beyond the
pressure point.
The automatic transmission shifts to a
lower gear depending on the engine speed.
X Ease off the accelerator pedal once the
desired speed is reached.
The automatic transmission shifts back up.
Rocking the vehicle free Rocking the vehicle free by shifting back and
forth between transmission positions Dand R
can help to free a vehicle that has become
stuck in mud or snow.
The vehicle's engine management restricts
switching between transmission positions D
and Rto speeds up to a maximum of 5 mph
(9 km/h).
To shift back and forth between transmission
positions Dand R, move the DIRECT SELECT
lever up and down past the point of resist-
ance. AGILITY SELECT switch
Use the AGILITY SELECT switch to change the
drive program. Depending on the drive pro-
gram selected the following vehicle charac-
teristics will change:
R the drive (engine and transmission man-
agement)
R the suspension
R the steering Automatic transmission
167Driving and parking Z

R
the availability of the ECO start/stop func-
tion (Y page 161)
R the climate control settings
- Dual-zone automatic climate control
(Y page 140)
- vehicles for Canada: three-zone auto-
matic climate control (Y page 142)
R the rear window defroster operation period
(Y page 148)
R the performance of the seat heating
(Y page 112)
Each time you start the engine using the
SmartKey or the Start/Stop button, drive pro-
gram Cis activated. For further information
about starting the engine, see (Y page 159).X
Push AGILITY SELECT switch 0043up or
down, until the desired drive program is
selected.
The selected drive program appears in the
multifunction display. After five seconds
the display goes out and the status icon of the selected drive program appears.
In addition, the current drive program set-
tings are displayed in the Audio 20/
COMAND display.
Available drive programs: I
Individual Individual settings
S+
Sport Plus Extremely sporty driving
characteristics
S
Sport Sporty driving character-
istics C
Comfort Comfortable and econom-
ical driving characteristics E
Eco Particularly economical
driving characteristics
Additional information for drive programs
(Y page 168).
Using the steering wheel paddle shifters, you can temporarily change gears yourself. For
further information on the manual drive pro-
gram (Y page 169). Drive programs
Drive program I (Individual) In drive program
Ithe following properties of
the drive program can be selected:
R the drive (engine and transmission man-
agement)
R the suspension
R the steering
To permanently select the gears in the drive
program Iusing the steering wheel paddle
shifters, select the permanent manual gear-
shift program.
Information about the selection of drive pro-
gram Iwith COMAND or Audio 20 can be
found in the Digital Operator's Manual.
Drive program S+ (Sport Plus) Drive program
S+is characterized by the fol-
lowing:
R the vehicle delivers extremely sporty han-
dling characteristics
R the vehicle pulling away in first gear
R the automatic transmission shifting up
later
R the fuel consumption possibly being higher
as a result of the later automatic transmis- sion shift points 168
Automatic transmissionDriving an
d parking

R
the suspension exhibits particularly stiff
springing and damping settings (vehicles
with AIRMATIC)
R the ECO start/stop function is not available
Drive program S (Sport) Drive program
Sis characterized by the fol-
lowing:
R the vehicle exhibits sporty driving charac-
teristics
R the vehicle pulling away in first gear
R the automatic transmission shifting up
later
R the fuel consumption possibly being higher
as a result of the later automatic transmis- sion shift points
R the suspension exhibits hard springing and
damping settings (vehicles with AIRMATIC)
Drive program C (Comfort) Drive program
Cis characterized by the fol-
lowing:
R the vehicle delivers comfortable, economi-
cal handling characteristics.
R the vehicle pulling away more gently in
forward and reverse gears, unless the
accelerator pedal is depressed fully.
R increased sensitivity. This improves driving
stability on slippery road surfaces, for
example.
R optimal fuel consumption resulting from
the automatic transmission shifting up
sooner. The vehicle is driven in the low
engine speed range and the wheels are less
likely to spin. Drive program E (Eco) Drive program
Eis characterized by the fol-
lowing:
R the vehicle exhibits comfortable, economi-
cal handling characteristics
R the vehicle pulling away more gently in
forward and reverse gears, unless the
accelerator pedal is depressed fully.
R increased sensitivity. This improves driving
stability on slippery road surfaces, for
example.
R optimal fuel consumption resulting from
the automatic transmission shifting up
sooner. The vehicle is driven in the low
engine speed range and the wheels are less
likely to spin.
R during deceleration, the engine is discon-
nected from the drive train. The vehicle
uses kinetic energy and consumes less fuel (overrun mode).
R the performance of air-conditioning system
and heating are reduced Manual gear shifting
General notes 0043
Left steering wheel paddle shifter: shifts
down
0044 Right steering wheel paddle shifter: shifts
up
Using the steering wheel paddle shifters, you can temporarily change gears yourself. The
transmission must be in position D. Automatic transmission
169Driving and parking Z

Activating
X
Shift the transmission to position D.
X Pull the left or right steering wheel paddle
shifter (Y page 169).
Manual gear shifting is activated tempora-
rily. The selected gear appears in the mul-
tifunction display.
Shifting gears Pulling on the left or right steering wheel pad-
dle shifter, allows you to shift gears yourself
for a limited time. Depending on which paddle
shifter is pulled, the automatic transmission
immediately shifts into the next gear down or up, if permitted.
X To shift up: pull the right-hand steering
wheel paddle shifter (Y page 169).
The automatic transmission shifts up to the
next gear.
If the maximum engine speed on the cur-
rently engaged gear is reached and you
continue to accelerate, the automatic
transmission automatically shifts up in
order to prevent engine damage.
X To shift down: pull on the left-hand steer-
ing wheel paddle shifter (Y page 169).
The automatic transmission shifts down to
the next gear.
If the engine exceeds the maximum engine speed when shifting down, the automatic
transmission protects against engine dam-
age by not shifting down.
Automatic down shifting occurs when
coasting.
Shift recommendation The gearshift recommendations assist you in
adopting an economical driving style. The rec- ommended gear is shown in the multifunction
display.
X Shift to recommended gear 0044according
to gearshift recommendation 0043when
shown in the multifunction display of the
instrument cluster.
Deactivating If you have activated manual gear shifting, it
will remain active for a certain amount of
time. Under certain conditions the minimum
amount of time is extended, e.g. in the case of lateral acceleration, during an overrun phase
or when driving on steep terrain.
If manual gear shifting is deactivated, the
gears will be selected automatically.
You can also deactivate manual gear selec-
tion:
X Pull on the right-hand steering wheel pad-
dle shifter and hold it in place (Y page 169).
or
X Use the DIRECT SELECT lever to switch the
transmission position.
or
X Use the AGILITY SELECT switch to change
the drive program (Y page 167).
Manual gear selection is deactivated. 170
Automatic trans
missionDriving and parking

Problems with the transmission
Problem
Possible causes/consequences and
0050
0050Solutions The transmission has
problems shifting gear. The transmission is losing oil.
X Have the transmission checked at a qualified specialist work-
shop immediately. The acceleration ability
is deteriorating.
The transmission no
longer changes gear. The transmission is in emergency mode.
It is only possible to shift into
secondgear and reverse gear.
X Stop the vehicle.
X Shift the transmission to position P.
X Switch off the engine.
X Wait at least ten seconds before restarting the engine.
X Shift the transmission to position Dor R.
If D is selected, the transmission shifts into secondgear; ifRis
selected, the transmission shifts into reverse gear.
X Have the transmission checked at a qualified specialist work-
shop immediately. Transfer case
This section is only valid for vehicles with 4-
wheel drive (4MATIC). Power is always trans- mitted to both axles.
! Performance tests may only be carried
out on a 2-axle dynamometer. The brake
system or transfer case could otherwise be
damaged. Contact a qualified specialist
workshop for a performance test.
! To prevent ESP ®
from intervening, the
ignition must be switched off (SmartKey or
the Start/Stop button in position 0or 1) if:
R the electric parking brake is being tested
on a brake dynamometer.
R the vehicle is being towed with only one
axle raised (not permitted for vehicles
with 4MATIC).
The brake system could otherwise be dam-
aged.
! Vehicles with 4MATIC must not be towed
with either the front or the rear axle raised,
as doing so will damage the transmission. Refueling
Important safety notes
G
WARNING
Fuel is highly flammable. If you handle fuel
incorrectly, there is a risk of fire and explo-
sion.
You must avoid fire, open flames, creating
sparks and smoking. Switch off the engine
and, if applicable, the auxiliary heating before refueling. G
WARNING
Fuel is poisonous and hazardous to health.
There is a risk of injury.
You must make sure that fuel does not come into contact with your skin, eyes or clothing
and that it is not swallowed. Do not inhale fuel
vapors. Keep fuel away from children. Refueling
171Driving and parking
Z