requirements are low. When power output
requirements are low, the electric motor pow-
ers the vehicle. When power output require-
ments are high, the combustion engine is
switched on, even during a journey. When the vehicle is stationary, the combustion engine
is usually switched off. Consequently, there is usually no engine idling as with combustion
engine vehicles.
For pulling away and accelerating, the electric
motor supports the internal combustion
engine using the power stored in the high-
voltage battery. In addition, the power is used
for partially electric driving, operation of the
electric coolant compressor and to support
the 12 V on-board electrical system. In this
way the hybrid drive helps to reduce your
vehicle's fuel consumption.
Observe the driving tips on hybrid operation
(Y page 281).
RBS (Recuperative Brake System) If you release the accelerator pedal when the
vehicle is in motion, overrun recuperation is
initiated. The electric motor is operated as a
generator when in overrun mode and when
you brake. Hybrid technology converts the
kinetic energy of the vehicle into electricity
and stores it in the high-voltage battery. Important safety notes
All of the vehicle's systems remain active, if: R the vehicle is stationary,
R the combustion engine is switched off and
R the READY-indicator in the instrument clus-
ter is lit.
If you remove your foot from the brake pedal
while in transmission position D or R, the
vehicle could pull away automatically.
Observe the notes on the READY display of
the ECO start/stop function (Y page 282).
Vehicles with an electric motor generate sig-
nificantly less noise than vehicles with inter-
nal combustion engines. As a result, in certain situations your vehicle may not be heard by
other road users. This is the case, for exam-
ple, when you are parking and your vehicle is not seen by other road users.
This requires you to adopt a particularly antic-
ipatory driving style, as it is necessary to allow
for the possibility that other road users may
behave unpredictably. Hybrid operation
273Driving and parking Z
Hybrid system overview
:
Recuperative Brake System
; 12 V battery
= High-voltage battery
? Electric cables for the high-voltage electrical system
A High-voltage battery cooling
B Electric refrigerant compressor
C Power electronics cooling
D Electric vacuum pump
E Transmission with electric motor
F Power electronics (DC/AC converter or DC/DC converter)
You can deactivate the hybrid system manually. For further information on the high-voltage
disconnect device, see (Y page 43).274
Hybrid operationDriving and parking
This shows the electric output from the
electric motor, e.g. when driving using the
electric motor or in boost mode.
When the motor is switched on, the display is at :. When driving solely on electricity,
the display fills up from :to; depending
on the power output demanded as a result
of pressing the accelerator pedal.
If the display has reached limit ;, addi-
tional power output can only be provided by
the combustion engine. The combustion
engine starts. If the display is approaching
limit ;and you remove your foot from the
accelerator pedal, the display empties
again. The combustion engine is not
switched on. At low speeds, you can
thereby control the electric drive usage so
that you only drive in electric mode.
R Area =to? (CHARGE):
This shows the recuperated energy which is
stored in the high-voltage battery as elec-
trical energy.
When the display reaches limit ?, the max-
imum recuperative braking power has been exhausted. The conventional brakes are
activated.
Operating the on-board computer You can display the current operating condi-
tion of the hybrid system in the multifunction
display and the COMAND display
(Y page 276).
You can display the current operating condi-
tion of the hybrid system in the multifunction display and the Audio 20/COMAND Online
display (Y page 276).
In the Audio 20/COMAND Online display, you
can also call up a graphic display of the fuel
consumption and generated electricity
(Y page 279). Menus and submenus
Selecting messages in the Audio 20/
COMAND Online display X
Press the Øbutton on the controller.
The vehicle menu appears.
X To select Energy
Energy flow flow: turn and press the
controller.
The energy flow is displayed.
X To select Consumption Consumption: turn and press the
controller.
Fuel consumption and the electric energy
generated are displayed.
X To exit the display: press the %button
on the controller.
Selecting the energy flow display in the multifunction display X
Use Ñ 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 : or9 to select Energy flow
Energy flow .
The energy flow is displayed.
Energy flow display Overview
:
Internal combustion engine
; Electric motor
= Charge status of the high-voltage battery 276
Hybrid operationDriving and parking
Driving using the electric motor and
charging the high-voltage battery The electric motor is being operated as an
alternator, e.g. in overrun mode and when
braking. The kinetic energy of the vehicle is
converted into electrical energy. The high-
voltage battery is charging.
The arrows for the energy flow are shown in
green. The combustion engine is shown in
dark grey.
Displaying the total range The approximate range is based on the cur-
rent driving style.
X Use Ñ 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
Trip menu.
X Confirm by pressing aon the steering
wheel.
X Press :or9 to select the approxi-
mate total range. Displaying fuel consumption and gen-
erated electrical energy :
Fuel consumption
; Electrical energy generated
Every bar of the graph displays the average
value for one minute.
Fuel consumption indicator :may differ
from the indicator in the From start From starttrip
computer in the Trip
Tripmenu.
To reset values: the values are reset along
with the From start
From start trip computer
(Y page 301).
X To select Consumption
Consumption: turn and press the
controller.
The Audio 20/COMAND Online display
shows fuel consumption :and electrical
energy generated ;for the last
15 minutes driven. Starting the engine
READY indicator X
Switch the ignition on.
X Depress the brake pedal. Hybrid operation
279Driving and parking Z
X
Observe the notes on starting the engine
(Y page 187).
X Turn the key to position 3in the ignition
lock (Y page 188) or press the Start/Stop
button once (Y page 188).
The vehicle is operational when READY indi-
cator :lights up.
Noiseless start The vehicle starts in electric mode without the
internal combustion engine. The internal
combustion engine starts only after the
power demanded by the driver exceeds the
available power that the electric motor can
currently provide.
Noiseless start operation is dependent on the
outside temperature and the operating tem-
perature of the internal combustion engine.
The vehicle is operational when READY indi-
cator :lights up. Pulling away
X Depress the brake pedal and keep it
depressed.
X Shift the transmission to position Dor R.
X Release the brake pedal.
Further information on pulling away
(Y page 189). Driving
AGILITY SELECT switch Drive programs
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 R
the availability of the ECO start/stop func-
tion (Y page 282)
R the climate control settings
- THERMATIC (1-zone) (Y page 153)
- THERMATIC (2-zone) (Y page 157)
- THERMOTRONIC (3-zone) (Y page 160)
R the rear window heating operation period
(Y page 167)
R the performance of the seat heating
(Y page 123)
If the ignition is switched off for less than four
hours, the previously selected drive program
is activated when the engine is next started. If the ignition is switched off for more than four
hours, drive program Cis activated when the
engine is next started. X
Push AGILITY SELECT switch :up 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 Online display.
Available drive programs: I
Individual Individual settings
S+
Sport Plus R
Extremely sporty driving
style with boost mode
R Electric-only drive is not
possible
R The ECO start/stop
function is not available 280
Hybrid operationDriving and parking
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 283)
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 277)
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 275).
The "extended overrun" operating mode is
deactivated again if:
R the combustion engine starts
R you depress the brake pedal Hybrid operation
283Driving and parking Z
Parking
X Apply the electric parking brake.
The red !indicator lamp in the instru-
ment cluster lights up.
X Use the DIRECT SELECT lever to shift the
automatic transmission to P.
X Switch the ignition off.
The READY indicator in the instrument clus-
ter goes out.
Further information on parking and switching off the internal combustion engine
(Y page 212). 284
Hybrid operationDriving and parking
Towing a trailer
Important safety notes
G
WARNING
You could lose control of the vehicle/trailer
combination if it begins to swerve. The vehi-
cle/trailer combination could even overturn.
There is a risk of an accident.
On no account should you attempt to
straighten out the vehicle/trailer combina-
tion by increasing speed. Decrease your
speed and do not countersteer. Brake if nec-
essary. G
WARNING
If the maximum the permissible load for a car- rier system is exceeded, the carrier could
come loose from the vehicle and endanger
other road users. There is a risk of an accident and injury.
Never exceed the permissible noseweight
when using a carrier.
Exceeding the maximum permissible nose-
weight of the trailer drawbar on the ball cou-
pling may cause damage to the following: R your vehicle
R the trailer
R the ball coupling
R the trailer tow hitch
The vehicle/trailer combination could
become unstable.
If the noseweight used is lower than the min- imum permissible noseweight, the vehicle/
trailer combination could also become unsta- ble.
To avoid hazardous situations:
R make sure to check the noseweight before
each journey
R use a drawbar noseweight as close as pos-
sible to the maximum noseweight R
do not exceed the maximum permissible
noseweight
R do not use a noseweight lower than the
minimum noseweight
Make sure that the following values are not
exceeded:
R the permissible trailer drawbar noseweight
R the permissible trailer load
R the permissible rear axle load of the towing
vehicle
R the maximum permissible gross vehicle
weight of both the towing vehicle and the
trailer
The applicable permissible values, which
must not be exceeded, can be found:
R in your vehicle documents
R on the identification plates of the trailer tow
hitch and the trailer
R on the vehicle identification plate
If the values differ, the lowest value applies.
You will find the values approved by the man-
ufacturer on the vehicle identification plates
and those for the towing vehicle under "Tech- nical data" (Y page 480). 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.
When reversing the vehicle towards the
trailer, make sure there is nobody between
the trailer and the vehicle.
Couple and uncouple the trailer carefully. If
you do not couple the trailer to the towing
vehicle correctly, the trailer could become
detached.
When towing a trailer, your vehicle's handling
characteristics will be different in comparison to when driving without a trailer. 286
Towing a trailerDriving an
d parking