Page 254 of 438

a generator and stores the recovered energy
in the high-voltage battery
Rwhen the brakes are applied lightly, the vehi-
cle is slowed down further by the electric
motor. This increases the energy recovery
taking place (
Ypage 240). The electric motor
operates as a generator and stores the recov-
ered energy in the high-voltage battery
Rwhen the brakes are applied with greater
force, the service brakes are also used to slow
the vehicle down. The two systems work
together
Urban driving
Energy is recuperated during frequent deceler-
ation and stopping in city traffic.
The vehicle can be driven by the electric motor
alone up to a speed of approximately 81 mph
(130 km/h).
The vehicle is driven by the electric motor alone
only when all conditions for the automatic
engine switch-off are fulfilled.
Further information on the automatic engine
switch-off (
Ypage 252).
Driving on inter-urban roads
The following phases are possible when driving
on inter-urban roads:
Rrapid acceleration (boost mode)
Rconstant energy consumption
Renergy recuperation
Relectric operation mode
A great deal of recovered energy may be avail-
able, depending on the route profile. This
reduces consumption and emissions.
Highway driving
During highway driving, fuel consumption and
emissions are favorably influenced in particular
by reduced power losses.
The internal combustion engine will be switched
off automatically, if:
Rthe driver removes his or her foot from the
accelerator pedal in drive program Eand a
speed of 81 mph (130 km/h) is not exceeded
Rthe driver removes his or her foot from the
accelerator pedal in drive program E+and a
speed of 112 mph (180 km/h) is not excee-
ded
Further information on the automatic engine
switch-off (
Ypage 252).
ECO start/stop function
General notes
The ECO start/stop function switches the inter- nal combustion engine off automatically when
the vehicle stops moving and at high speeds
(
Ypage 253).
All vehicle systems remain active, e.g. the auto-
matic climate control.
The ECO start/stop function is only available in
drive programs Eand E+. Electric-only operation
is only possible in drive programs Eand E+.
Additional information for drive programs Eand
E+ (
Ypage 250).
Automatic engine switch-off
The engine is switched off automatically, includ-
ing when:
Rthe driver removes his or her foot from the
accelerator pedal in drive program Eand a
speed of 81 mph (130km/ h)is not exceeded
(
Ypage 253)
Rthe driver removes his or her foot from the
accelerator pedal in drive program E+and a
speed of 112 mph (180 km/h) is not excee-
ded (
Ypage 253)
Rthe engine has reached its operating temper- ature
Rthe driver’s seat belt is fastened and the
driver’s door is closed
Rthe driver only slightly depresses the accel-
erator pedal in order to, for example, maintain
the current speed for a limited distance
Rthe hood is closed and engaged properly
Rthe high-voltage battery is charged suffi-
ciently
Rno malfunctions are present in the hybrid
drive system
The internal combustion engine will not be
switched off automatically, if:
Rthe self-diagnosis function of the engine con-
trol unit is still active
Rthere is a malfunction in the hybrid drive sys-
tem
Rthe climate control of the vehicle requires it
Rthe high-voltage battery is being charged
(Ypage 246)
Rautomatic emissions tests are running
252PLUG‑IN HYBRID operation
Driving and parking 
     
        
        Page 297 of 438

Display messagesPossible causes/consequences andMSolutions
#
See Operator'sMan ‐ual
The battery is no tbein gcharged.
A warning tone also sounds.
Possibl ecauses are:
Radefective alternato r
Rdefective powerelectronics (PLUG-IN HYBRID vehicles)
Ra torn poly-V-belt
Ramalfunction in th eelectronics
!Do no tcontinu edriving. The engin ecould otherwise overheat.
XPull ove rand stop th evehicl esafely and switch off th eengine, pay-
ing attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 189).
XConsult aqualified specialist workshop .
#
StopVehicl eSeeOperator' sManual
The battery is no longer bein gcharged and th ebattery charg elevel is
to olow.
A warning tone also sounds.
XPull ove rand stop th evehicl esafely and switch off th eengine, pay-
ing attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 189).
XObserv eth einstruction sin th e# See Operator' sManualdisplay message .
XConsultaqualified specialist workshop .
#
StopVehicl eLeaveEngine Runnin g
The battery charg elevel is to olow.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions. Do no tcontinu edrivin g
under any circumstances.
XLeav eth eengin erunning.
XWait until th edisplay message disappear sbefore pullin gaway.
#
Start Engine SeeOperator' sManual
The engin eis switched off and th ebattery charg elevel is to olow.
XSwitc hoff electrical consumer sthat you do no tneed, suc has th e
rear window defroste rand interior lighting .
XLeaveth eengin erunnin gfor afew minute sor drive alon gdistance.
The battery is bein gcharged.
Display messages29 5
On-board computer and displays
Z 
     
        
        Page 315 of 438

Display messagesPossible causes/consequences andMSolutions
Becausethere is interferenc efrom astron gsource of radi owaves, th e
ke yis no tdetecte dwhils tth eengin eis running.
A warning tone also sounds.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 189).
XInsertth eSmartKey int oth eignition loc kand bring int oke ymode.
Â
Remove 'Start 'But ‐ton and Insert Key
The SmartKey is continually undetected.
The SmartKey detection function has atemporar ymalfunction or is
faulty. Awarning tone also sounds.
XInser tth eSmartKey int oth eignition loc kand tur nit to th edesire d
position .
XVisitaqualified specialist workshop .
Warning and indicat orlamps in the instrume nt cluster
General notes
Some systems carry out aself-diagnosis when th eignition is switched on .Therefore ,som eindicator
and warning lamp smay ligh tup or flas htemporarily. This behavio ris non-critical .These indicator
and warning lamp sonly indicat e amalfunction if they ligh tup or flas hafter starting th eengin eor
whils tdriving.
Safety
Seat belts
Warning/
indicator
lam pNSignal type
Possible causes/consequences and M
Solutions
üNAfte rstarting th eengine, th ered seat belt warning lamp lights up for 6seconds .
The seat belt warning lamp remind sth edriver and fron tpassenger to faste ntheir
seat belts.
XFaste nyour seat belt (Ypage 49).
üNAfte rstarting th eengine, th ered seat belt warning lamp lights up. In addition , a
warning tone sounds for up to 6seconds.
The driver's seat belt is no tfastened.
XFaste nyour seat belt (Ypage 49).
The warning tone ceases .
Warning and indicator lamps in the instrument cluster313
On-board computer and displays
Z 
     
        
        Page 316 of 438

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
üNThe red seat belt warning lamp lights up after the engine starts, as soon as the
driver's or the front-passenger door is closed.
The driver or front passenger has not fastened their seat belt.
XFasten your seat belt (Ypage 49).
The warning lamp goes out.
There are objects on the front-passenger seat.
XRemove the objects from the front-passenger seat and stow them in a secure
place.
The warning lamp goes out.
üN The red seat belt warning lamp flashes and an intermittent audible warning
sounds.
The driver or front passenger has not fastened their seat belt. The vehicle is being driven faster than 15 mph (25 km/h) or has briefly been driven faster than 15 mph
(25 km/h).
XFasten your seat belt (Ypage 49).
The warning lamp goes out and the intermittent warning tone ceases.
There are objects on the front-passenger seat. The vehicle is being driven faster
than 15 mph (25 km/h) or has briefly been driven faster than 15 mph (25 km/h).
XRemove the objects from the front-passenger seat and stow them in a secure
place.
The warning lamp goes out and the intermittent warning tone ceases.
314Warning and indicator lamps in the instrument cluster
On-board computer and displays