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VIII
S A F E T Y
TRAJECTORY CONTROL SYSTEMS
Anti-skid regulation (ASR)
and electronic stability
programme (ESP)
The anti-skid regulation (also known as
Traction Control) optimises traction to
prevent skidding of the wheels, by act-
ing on the brakes of the driving wheels
and on the engine.
The electronic stability programme acts
on the brake of one or more wheels
and on the engine to keep the vehicle
o n t h e t r a j e c t o r y r e q u i r e d b y t h e d r i v e r . Deactivation
I n e x c e p t i o n a l c o n d i t i o n s ( s t a r t i n g a
vehicle which is bogged down, stuck
in snow, on soft ground...), it may be
advisable to deactivate the ASR and
ESP systems, so that the wheels
can move freely and regain grip.
Press the "ESP OFF" button, lo-
cated in the centre of the dash-
board.
If this warning lamp comes
on in the instrument panel
and the indicator lamp on the
button comes on, this indi-
cates that the ASR and ESP
systems are deactivated.
T h i s i s i n d i c a t e d b y fl a s h i n g
of this warning lamp on the
instrument panel.
Activation
These systems are activated auto-
matically each time the vehicle is
started.
They come into operation in the event
o f a g r i p o r t r a j e c t o r y p r o b l e m . Intelligent Traction Control
system *
Your vehicle has a system to help
driving on snow.
This automatic system continuously
c h e c k s f o r s i t u a t i o n s o f d i f fi c u l t s u r -
face adhesion that could make it dif-
fi c u l t t o m o v e o f f o r m a k e p r o g r e s s
on deep fresh snow or compacted
snow.
In these situations, the system takes
over from the
ASR system by opti-
mising the amount of wheel slip to
p r o v i d e t h e b e s t t r a c t i o n a n d t r a j e c -
tory control, even without snow tyres
and with or without chains.
I n e x t r e m e l y s e v e r e c o n d i t i o n s ( s n o w
on top of ice, sand, deep mud…), it
can be useful to deactivate the ESP/
ASR systems to allow a degree of
wheel spin and so recover grip.
* Depending on engine type.
