Driving
running. In this case power is consumed when
none is being generated.
When the engine is running
Engine management and
emission control system
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.
In these situations you will be aware that the
power management system is intervening to
control the distribution of electrical power.
Introduction
WARNING
When the vehicle is parked for long peri-
ods
●
Because of the high temperatures which
can occur in the exhaust purification sys-
tem (catalytic converter or particulate fil-
ter), do not park the vehicle where the ex-
haust can come into contact with flamma-
ble materials under the car (e.g. on grass or
at the forest edge). Fire hazard!
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.
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.
●
Do not apply wax underneath the vehicle
around the area of the exhaust system: Fire
hazard!
Control lamps
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.
With the engine switched off
It lights up
For example, if you listen to the sound system
with the engine switched off the battery will
run down.
Fault in the emission control system. (e.g. faulty
lambda sensor).
Reduce speed and drive carefully to the nearest spe-
cialised workshop to have the engine checked.
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*.
Flashes
Combustion fault which could damage the catalytic
converter.
This driver indicator tells you that you must
start the engine so that the battery can re-
charge.
Reduce speed and drive carefully to the nearest spe-
cialised workshop to have the engine checked.
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