198Intelligent technology
The traction control system (ASR) helps the car to start moving, accelerate
and climb a gradient in slippery conditions where this may otherwise be dif-
ficult or even impossible.
How it works
The ASR works automatically, i.e. without the driver's involvement. With the
aid of the ABS sensors , the ASR monitors the speed of the driven wheels
⇒ page 196. If the wheels start to spin, the engine speed is reduced auto-
matically to match the amount of grip available. The system is active across
the entire speed range.
The ASR works in conjunction with the ABS. If a failure occurs in the ABS,
the ASR will also stop working.
In general, the ASR should be left switched on at all times. It should only be
switched off manually in particular circumstances where a certain amount of
wheel slip may be desirable. Examples:
● when driving with snow chains
● when driving in deep snow or on loose surfaces
● when rocking the vehicle backwards and forwards to free it.
The ASR should be switched on again afterwards as soon as possible.
Note
To ensure that the ASR works properly, all four wheels must be fitted with
identical tyres. The difference in size of the wheels may lead to an unde-
sired reduction in engine power. Also see ⇒ page 255.Brakes
General notes
New brake pads
New brake pads do not provide optimal performance during the first
200 km; first they must be “run in”. However, the reduced braking capacity
may be compensated by pressing on the brake pedal a little harder. Avoid
overloading the brakes during run-in.
Wear
The rate of wear on the brake pads depends a great deal on how you drive
and the conditions in which the vehicle is operated. Negative factors are, for
instance, city traffic, frequent short trips or hard driving with abrupt starts
and stops.
Wet roads or road salt
In certain conditions, such as in heavy rain, or after washing the vehicle or
driving through water, the full braking effect can be delayed by moisture (or
in winter by ice) on the discs and brake pads. In this case the brakes should
be dried by pressing the brake pedal several times.
The effectiveness of the brakes can also be temporarily reduced if the vehi-
cle is driven for some distance without using the brakes when there is a lot
of salt on the road in winter. In this case, the layer of salt on the brake discs
and pads has to wear off before braking.
Corrosion
There may be a tendency for corrosion to form on the discs and dirt to build
up on the brake pads if the vehicle is used infrequently or the brakes are
not used very often.
If the brakes are not used frequently, or if rust has formed on the disks, it is
advisable to clean off the pads and disks by braking firmly a few times at a
moderately high speed ⇒
.
