Driver assistance systems
brake on gravel or on fresh snow on a
slippery surface. WARNING
● The anti-lock brake system cannot defy the
laws of physics. Slippery and wet roads are
dangerous even with ABS! If you notice that
the ABS is working (to counteract locked
wheels under braking), you should reduce
speed immediately to suit the road and traffic
conditions. Do not let the extra safety fea-
tures tempt you into taking any risks when
driving.
● The effectiveness of ABS is also determined
by the tyres fitted ››› page 175.
● If the ru
nning gear or brake system is modi-
fied, the effectiveness of the ABS could be se-
verely limited. Drive wheel traction control system
(ASR)
The traction control system prevents the driv-
en wheels from spinning when the vehicle is
accelerating.
Description and operation of the traction
control system during acceleration (ASR
On front-wheel drive vehicles, the ASR sys-
tem intervenes, reducing engine power and
preventing the driven wheels from slipping
during acceleration. The system works in the entire speed range in conjunction with ABS.
If a failure occurs in the ABS, the ASR will al-
so stop working.
TCS helps the car to start moving, accelerate
and climb a gradient in slippery conditions
where this may otherwise be difficult or even
impossible.
The ASR automatically switches on when the
engine is started. If necessary, it may be
turned on or off by briefly pushing the button
on the centre console.
When the ASR is switched off, the
OFF warning lamp will light up. The ASR should
normally be left on. Only in exceptional cir-
cumstances, when slipping of the wheels is
desired, should it be disconnected.
●
With compact temporary spare wheel.
● When using the snow chains.
● When driving in deep snow or on soft ter-
rain.
● When the vehicle is bogged-down, to free it
by “rocking.”
The ASR should be switched on again as
soon as possible. WARNING
● Remember that not even the ASR can defy
the laws of physics. This should be kept in
mind, particularly on slippery and wet roads
and when towing a trailer. ●
Always adapt your driving style to suit the
condition of the roads and the traffic situa-
tion. The greater safety provided by the ASR
should not encourage you to run any risks. CAUTION
● To ensure that the ASR works correctly,
identical tyres should be fitted on all four
wheels. Any differences in the rolling radius
of the tyres can cause the system to reduce
engine power when this is not desired.
● Any modifications made to the vehicle (for
example, to the engine, brake system, run-
ning gear or to the combination of wheels
and tyres) may affect the operation of the
ABS and ASR. XDS*
When taking a curve, the driveshaft differen-
tial mechanism allows the outer wheel to turn
at a higher speed than the inner wheel. In
this way, the wheel that is turning faster (out-
er wheel) receives less drive torque than the
inner wheel. This may mean that in certain
situations the torque delivered to the inner
wheel is too high, causing the wheels to
spin. On the other hand, the outer wheel is
receiving a lower drive torque than it could
transmit. This causes an overall loss of lateral
grip on the front axle, resulting in understeer
or “lengthening” of the trajectory.
»
137
Technical specifications
Advice
Operation
Safety
