Driving
Since the luggage rack increases the aer o-
dynamic dr ag
of the vehicle, you should re-
move it when not needed. At speeds of
100-120 km/h (62-75 mph), this will save 12%
of fuel.
Save electrical energy
The engine drives the alternator, thereby
generating electricity. This implies that any
increase in power consumption also increa-
ses fuel consumption! For this reason, switch
off any unneeded electrical devices. Devices
that use a lot of electricity includes the blow-
er at a high setting, the rear window heating
or the seat heating*.
Power management
This system helps to ensur
e relia-
ble starting The power management controls the distri-
bution of el
ectrical ener
gy and thus helps t
o
ensure that there is always enough power
available to start the engine.
If a vehicle with a conventional electrical sys-
tem is left parked for a long time, the battery
will gradually lose its charge because certain
electrical devices, such as the electronic
gearbox lock continues to draw current even
when the ignition is off. In some cases there may not be enough power available to start
the engine.
Your v
ehicle is equipped with an intelligent
power management system to control the
distribution of electrical energy. This signifi-
cantly improves reliability when starting the
engine, and also prolongs the useful life of the
battery.
The main functions incorporated in the power
management system are battery diagnosis,
residual current management and dynam-
ic power management.
Battery diagnosis
The battery diagnosis function constantly
registers the condition of the battery. Sensors
detect the battery voltage, battery current
and battery temperature. This enables the
system to calculate the current power level
and charge condition of the battery.
Residual current management
The residual current management reduces
power consumption while the vehicle is
parked. It controls the supply of power to the
various electrical devices while the ignition is
switched off. The system takes the battery di-
agnosis data into consideration.
Depending on the power level of the battery,
switch off the individual electrical devices
one after the other to prevent the battery from losing too much charge and to ensure
that the engine can be started r
eliably.
Dynamic power management
While the vehicle is moving, this function dis-
tributes the available power to the various
electrical devices and systems according to
their requirements. The power management
ensures that on-board systems do not con-
sume more electrical power than the alterna-
tor can supply, and thus maintains the maxi-
mum possible battery power level. Note
Start and driving
running. In this case power is consumed when
none is being gener at
ed.
In these sit
uations you will be aware that the
power management system is intervening to
control the distribution of electrical power.
When the vehicle is parked for long peri-
ods
If you do not drive your vehicle for a period of
several days or weeks, the power manage-
ment will gradually shut off the electrical de-
vices one by one or reduce the amount of
current they are using. This limits the amount
of power consumed and helps to ensure reli-
able starting even after a long period. Some
convenience functions, such as remote vehi-
cle opening, may not be available under cer-
tain circumstances. These functions will be
restored when you switch on the ignition and
start the engine.
With the engine switched off
For example, if you listen to the sound system
with the engine switched off the battery will
run down.
If the energy consumption means there is a
risk that the engine will not start, a text will
appear in vehicles with a driver information
system*.
This driver indicator tells you that you must
start the engine so that the battery can re-
charge. When the engine is running
Although the alternator gener
ates electrical
power, the battery can still become dis-
charged while the vehicle is being driven. This
can occur when a lot of power is being con-
sumed but only a small amount supplied, es-
pecially if the battery is not fully charged ini-
tially.
To restore the necessary energy balance, the
system will then temporarily shut off the elec-
trical devices that are using a lot of power, or
reduce the current they are consuming. Heat-
ing systems in particular use a large amount
of electrical power. If you notice, for instance,
that the seat heating* or the rear window
heater is not working, they may have been
temporarily switched off or regulated to a
lower heat output. These systems will be
available again as soon as sufficient electri-
cal power is available.
You may also notice that the engine runs at a
slightly faster idling speed when necessary.
This is quite normal, and no cause for con-
cern. The increased idling speed allows the
alternator to meet the greater power require-
ment and charge the battery at the same
time. Engine management and
emission control system
Intr
oduction WARNING