ECU MERCEDES-BENZ C-CLASS SALOON 2014 Workshop Manual

Acceleration
Depending on the operating mode, pulling
away and driving under low load conditions
are performed:
R entirely by electric propulsion
R in combination with the internal combus-
tion engine
When accelerating at an increased or full
load, boost mode is utilised. The electric
motor supports the internal combustion
engine by providing additional torque when
the accelerator is depressed rapidly.
Overrun mode or braking
There are three possible operating modes
when the hybrid vehicle is decelerating: R When coasting and decelerating, energy
recuperation is already taking place
(Y page 269). The electric motor functions
as an alternator and stores the recuperated
energy in the high-voltage battery.
R When braking gently, the electric motor
increases the deceleration of the vehicle.
Energy recuperation is increased
(Y page 269). The electric motor functions
as an alternator and stores the recuperated energy in the high-voltage battery.
R During heavy braking, the service brake is
also used to slow down the vehicle. Both
systems work together.
Driving in the city
Energy is recuperated during frequent decel-
eration and stopping in city traffic.
The vehicle can be driven by the electric
motor alone up to a speed of approximately
35 km/h, e.g.:
R while approaching a traffic light
R in stop-and-start traffic
The vehicle is driven by the electric motor
alone only when all conditions for the auto-
matic engine switch-off are fulfilled.
Further information on the automatic engine
switch-off (Y page 280). Driving on inter-urban roads
Three phases are possible when driving on
inter-urban roads:
R rapid acceleration (boost mode)
R constant energy consumption
R energy recuperation
Depending on the characteristics of the
route, there may be a lot of recuperated
energy available. This reduces consumption
and emissions.
Driving on the motorway
When driving on a motorway, the following
have a particularly positive effect on fuel con- sumption and emissions:
R the decrease in wasted power when using
recuperative braking
R the decrease in wasted power in overrun
mode when the combustion engine is
switched off
Manoeuvring and turning
The hybrid drive makes it possible to manoeu- vre and turn solely using the electric motor.
ECO start/stop function General notes
The ECO start/stop function switches the
internal combustion engine off automatically
when the vehicle stops moving and at high
speeds (Y page 280).
All vehicle systems remain active, e.g. the
automatic climate control.
The ECO start/stop function is only available in drive programs C,Eand I. Electric-only
operation is only possible in drive programs C
and E. Hybrid operation
279Driving and parking Z

Automatic engine switch-off
The internal combustion engine is switched
off automatically if:
R the driver removes his foot from the accel-
erator pedal and a speed of 160 km/h is
not exceeded (Y page 280)
R the combustion engine and the transmis-
sion have reached operating temperature
R the driver's seat belt is fastened and the
driver's door is closed
R the driver only slightly depresses the accel-
erator pedal in order to, for example, main- tain the current speed for a limited distance
R the bonnet is closed and engaged properly
R the high-voltage battery is charged suffi-
ciently
R there are no faults in the hybrid system
The internal combustion engine will not be
switched off automatically, if:
R the self-diagnosis function of the engine
control unit is still active
R the climate control of the vehicle requires it
R the high-voltage battery is being charged
(Y page 274)
R automatic emissions tests are running
R the operating temperature of the engine,
transmission and catalytic converter has
not yet been reached
Automatic engine start
The internal combustion engine, which has
been automatically switched-off, starts auto-
matically in certain situations, when:
R the power demand from the driver via the
accelerator pedal is greater than the elec-
tric motor alone can provide
R the driver switches to drive program Sor S
+
R the driver has activated manual gearshift-
ing R
the charge level of the high-voltage battery
has reached the lower limit
R the settings of the automatic climate con-
trol require it, e.g. at external temperatures
above 30 †
Overrun mode
This operating mode is available in the speed
range below 160 km/h.
The combustion engine is switched off and is disconnected from the drive train.
The electric motor:
R simulates an overrun torque which is equiv-
alent to the overrun torque of the combus-
tion engine
R functions as a generator and produces the
necessary energy for the auxiliary consum- ers and charges the high-voltage battery
Extended overrun mode
Overrun mode allows you to increase the
vehicle range.
When the vehicle is in overrun operating
mode:
X Pull the right-hand steering wheel gearshift
paddle.
Energy recuperation is reduced to the min-
imal amount of energy required. The vehi-
cle rolls faster and further, e.g. on long and steep downhill gradients or while coasting
towards a set of traffic lights.
You can see the reduction in energy recuper-
ation in the electric motor CHARGE display
(Y page 272).
The "extended overrun" operating mode is
deactivated again if:
R the combustion engine starts
R you depress the brake pedal 280
Hybrid operationDriving and pa
rking

Coupling up a trailer
X Make sure that the transmission is in posi-
tion P.
X Apply the electric parking brake.
X Position the trailer horizontally behind the
vehicle.
X Couple up the trailer.
X Establish the electric connection between
the vehicle and the trailer.
X Check that the trailer lighting system is
working.
X Push the combination switch upwards/
downwards and check whether the corre-
sponding turn signal on the trailer is flash-
ing.
A connected trailer is only recognised when the electrical connection is established
correctly and when the lighting system is
working properly. The functioning of other
systems, e.g. ESP ®
, PARKTRONIC, Active
Parking Assist, Active Blind Spot Assist or
Lane Keeping Assist also depends on this. Uncoupling a trailer
G
WARNING
If you uncouple a trailer with an engaged over- run brake, you could trap your hand between
the vehicle and the trailer drawbar. This poses a risk of injury.
Do not uncouple a trailer with an engaged
overrun brake. G
WARNING
Vehicles with level control:
If you disconnect the trailer cable, the vehicle is lowered. This can cause you or others to
become trapped between the vehicle body
and tyres, or underneath the vehicle. This
poses a risk of injury.
Make sure that no-one is in the immediate
vicinity of the wheel arch or underneath the
vehicle when disconnecting the trailer cable. !
Do not disconnect a trailer with an
engaged overrun brake. Otherwise, your
vehicle could be damaged by the rebound- ing of the overrun brake.
! Remove the installed adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumper and the adapter cable.
X Make sure that the transmission is in posi-
tion P.
X Apply the electric parking brake.
X Secure the trailer against rolling away.
X Remove the trailer cable and decouple the
trailer. Folding in the ball coupling
G
WARNING
If you release the ball coupling or it does not
engage correctly when folding in, it will swing out. Within pivoting range of the ball coupling,
there is an increased risk of an accident and
injury.
Only release the ball coupling if the pivoting
range is unobstructed. Always make sure that the ball coupling engages when folding in.
Fold the ball coupling back in if you are not
using the trailer tow hitch. X Make sure that the vehicle is stationary and
the trailer cables are disconnected.
X Place the protective covering on the ball
coupling.
X Open the boot lid. 286
Towing a trailerDriving and parking

Fitting the adapter
!
Make sure that there is sufficient cable
play so that the cable cannot become
detached when cornering.
! Remove the installed adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumper and the adapter cable. X
Open the socket cover.
X Insert the plug connector with lug :into
groove =on the socket. Turn bayonet con-
nection ;clockwise to the stop.
X Let the cover engage.
X If you are using an adapter cable, secure
the cable to the trailer with cable ties. 288
Towing a trailerDriving and pa
rking

Trip menu
Standard display X
Press and hold the %button on the
steering wheel until the Trip
Tripmenu with
trip meter :and total distance
recorder ;is shown.
Displaying the range and current fuel
consumption X
Use ò on the steering wheel to call up
the list of menus.
X Press the :or9 button on the steer-
ing wheel to select the Trip
Tripmenu.
X Confirm by pressing aon the steering
wheel.
X Press the :or9 button to select
approximate range :and current fuel con-
sumption ;.
Approximate range :that can be covered is
calculated according to your current driving
style and the amount of fuel in the tank. If
there is only a small amount of fuel left in the fuel tank, the display shows a vehicle being refuelled
Cinstead of approximate
range :.
Recuperation display =shows you if energy
has been recuperated from the kinetic energy
in overrun mode and saved in the battery.
Recuperation display =depends on the
engine installed and is therefore not available
in all vehicles.
Information on the total electric range in
hybrid vehicles can be found in the "Hybrid
drive" section (Y page 276).
ECO display X
Use ò on the steering wheel to call up
the list of menus.
X Press the :or9 button on the steer-
ing wheel to select the Trip Tripmenu.
X Confirm by pressing aon the steering
wheel.
X Use the :or9 button to select ECO
DISPLAY.
If the ignition remains switched off for longer than four hours, the ECO display will be auto-
matically reset.
For further information on the ECO display,
see (Y page 211). 298
Menus and submenusOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions T!
÷
inoperative See inoperative See
Owner's Manual Owner's Manual EBD (electronic brake force distribution), ABS, ESP
®
, BAS,
PRE ‑SAFE ®
, HOLD function, hill start assist, ESP ®
trailer stabili-
sation, Crosswind Assist, adaptive brake lights, STEER CONTROL, Active Lane Keeping Assist and Active Blind Spot Assist are
unavailable due to a malfunction.
BAS PLUS, PRE‑SAFE ®
Brake, PRE ‑SAFE®
PLUS and COLLISION
PREVENTION ASSIST PLUS may also have failed.
In addition, the ÷,åand! warning lamps light up in the
instrument cluster and a warning tone sounds.
G WARNING
The brake system continues to function normally, but without the functions listed above. The front and rear wheels could therefore
lock, for example, if you brake hard.
The steerability and braking characteristics may be severely affec-ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. J
Brake immediately Brake immediately A malfunction has occurred while the HOLD function is active.
or
With the HOLD function activated, you have:
R opened the driver's door and released the seat belt or
R switched off the engine
A tone may also sound at regular intervals. If you attempt to lock the vehicle, the tone becomes louder.
You cannot start the engine.
X Paying attention to the traffic situation, immediately depress the
brake pedal firmly and hold until the display message disap-
pears.
X Secure the vehicle against rolling away (Y page 207).
You can restart the engine. !
Release parking Release parking
brake brake The red
!indicator lamp flashes and a warning tone sounds. A
condition for automatic release of the electric parking brake is not
fulfilled (Y page 209).
You are driving with the electric parking brake applied.
X Release the electric parking brake manually. 318
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions The red
!indicator lamp flashes and the yellow !warning
lamp is lit.
The electric parking brake is malfunctioning.
To release:
X Switch off the ignition and turn it back on.
X Release the electric parking brake manually.
To apply:
X Switch off the ignition and turn it back on.
X Apply the electric parking brake manually.
If the red !indicator lamp continues to flash:
X Do not drive on.
X Secure the vehicle against rolling away (Y page 439).
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Turn the front wheels towards the kerb.
X Consult a qualified specialist workshop. The yellow
!warning lamp lights up. The red !indicator
lamp flashes for about ten seconds after the electric parking brake
has been applied or released. It then goes out or remains lit.
The electric parking brake is malfunctioning.
X Switch off the ignition and turn it back on.
X Apply the electric parking brake.
If it is not possible to apply the electric parking brake:
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission
to P.
X Consult a qualified specialist workshop.
If it is not possible to release the electric parking brake manually:
X Release the electric parking brake automatically (Y page 209).
If the electric parking brake still cannot be released: X Consult a qualified specialist workshop. 320
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions !
Turn on the igni‐ Turn on the igni‐
tion to release tion to release
the parking brake the parking brake The red
!indicator lamp lights up.
You attempted to release the electric parking brake while the igni-
tion was switched off.
X Switch the ignition on. J
Check brake fluid Check brake fluid
level level There is insufficient brake fluid in the brake fluid reservoir.
In addition, the red Jwarning lamp lights up in the instrument
cluster and a warning tone sounds.
G WARNING
Braking efficiency 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 (Y page 207).
X Consult a qualified specialist workshop.
X Do not top up the brake fluid. This does not correct the fault. #
Check brake pad Check brake pad
wear wear The brake pads/linings have reached their wear limit.
X Visit a qualified specialist workshop. Collision Preven‐
Collision Preven‐
tion Assist Plus tion Assist Plus
currently unavail‐ currently unavail‐
able See Owner's able See Owner's
Manual Manual COLLISION PREVENTION ASSIST PLUS is temporarily inoperative.
Possible causes:
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
Once the causes listed above no longer apply, the display message goes out.
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 (Y page 207).
X Restart the engine. 322
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions Collision Preven‐
Collision Preven‐
tion Assist Plus tion Assist Plus
inoperative inoperative COLLISION PREVENTION ASSIST PLUS is temporarily inoperative
due to a malfunction. Adaptive Brake Assist may also have failed.
X Visit a qualified specialist workshop. PRE-SAFE inopera‐
PRE-SAFE inopera‐
tive See Owner's tive See Owner's
Manual 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. PRE-SAFE
PRE-SAFE
Functions
Functions
currently limited
currently limited
See Owner's Manual See Owner's Manual PRE
‑SAFE ®
PLUS or PRE ‑SAFE®
Brake is temporarily inoperative.
Possible causes:
R the function is impaired due to heavy rain or snow
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
Once the causes listed above no longer apply, the display message
goes out.
PRE ‑SAFE ®
PLUS and PRE ‑SAFE®
Brake are 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 (Y page 207).
X Restart the engine. PRE-SAFE PRE-SAFE
Functions
Functions
limited See Own‐
limited See Own‐
er's Manual er's Manual PRE
‑SAFE ®
PLUS or PRE‑ SAFE®
Brake is unavailable due to a mal-
function. BAS PLUS might also be deactivated.
X Visit a qualified specialist workshop. Display
messages
323On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions Radar sensors
Radar sensors
dirty See Owner's dirty See Owner's
Manual Manual At least one of the following driving systems or driving safety sys-
tems is temporarily restricted or inoperative:
R PRE-SAFE ®
PLUS
R PRE-SAFE ®
Brake
R COLLISION PREVENTION ASSIST PLUS
R Active Lane Keeping Assist
R Active Blind Spot Assist
R DISTRONIC PLUS
Possible causes:
R the sensors in the radiator trim and/or in the bumpers are dirty
R the function of the driving system and/or driving safety system
is impaired due to heavy rain or snow
A warning tone also sounds.
Once the causes listed above no longer apply, the display message
goes out. All driving systems/driving safety systems are operative 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 (Y page 207).
X Switch off the engine.
X Clean the sensors (Y page 401) in the following locations:
R in the radiator trim
R in the front bumper
R in the rear bumper, particularly in the middle of the rear
bumper
X Restart the engine.
The display message disappears. ü ü If this symbol appears in the multifunction display, a seat belt
tongue has been inserted into a rear seat belt buckle.
Further information on the status indicator for the rear seat belts
(Y page 50). 324
Display
messagesOn-board computer and displays