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Checking and refilling levels
Changing brake fluid
W e r
ecommend that you hav e the br
ak
e fluid
changed by a Technical Service. WARNING
If the brake fluid level is low or unsuita-
ble/old brak e fluid is used, the br
ake sys-
tem may fail or braking power may be re-
duced.
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Practical tips
CAUTION
If the water from the windscreen washer
does not contain enough anti-freez e
, it may
freeze on the windscreen and rear window,
reducing forward and rear visibility.
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Checking and refilling levels
soon as the ignition is switched on and the
engine st art
ed.
Wint er conditions
During the wint er
, the starting power may be
reduced, and if necessary, the battery should
be charged
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Practical tips
Checking the battery electrolyte
l e
vel The electrolyte level should be checked reg-
ularly in high-mileage vehicl
es, in hot coun-
tries and in ol
der batteries.
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Checking and refilling levels
disposed of appropriately and must not be
disposed of with ordinary household wast
e
.Energy management
Optimisation of the starting ca-pacity The power management controls the distri-
bution of electrical energy and thus helps to
ensur
e that ther
e 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 vehicle 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
regist ers the condition of the batt
ery. 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 reliably.
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
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Practical tips
current they are using. This limits the amount
of po w
er consumed and helps t o ensur
e r
eli-
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 generates 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 el
ectrical 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. Wheels
Wheel s and t
yres
Gener al not
es
Page 359 of 408
Wheels
Low profile tyres
L o
w pr ofil
e t
yres have a wider tread, a larger
wheel diameter and a lower sidewall height.
Therefore, its driving behaviour is more agile.
Low profile tyres may deteriorate more quick-
ly than standard tyres, for instance due to
strong knocks, potholes, manhole covers and
kerbs. Correct tyre pressure is very important
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Practical tips
New wheels and tyres It is best to have all wheels and tyres serviced
by a specialised workshop. There they hav
e
the r
equired knowledge, the special tools and
the corresponding spare parts.