VIII
126
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 trac-
tion to prevent skidding of the wheels,
by acting 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
on the trajectory required by the driver,
within the limits of the laws of physics.
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 in-
dicator lamp on the button comes
on, this indicates 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
of a grip or trajectory problem. 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
provide the best traction and trajec-
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.
