181
Driving
Vehicles with a manual gearbox
The system
is completely turned off by moving the control
B
all the way to
the right hand side (OFF engaged), or when the vehicle is stationary,
ignition off.
Vehicles with automatic gearbox / DSG automatic gearbox
To completely disengage the system, the selector lever must be placed in
one of the following positions:
P,
N,
R or
1 or
with the vehicle stopped and
the ignition turned off.
Safety First
Operating Instructions
Practical Tips
Technical Specifications
182
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Practical Tips
Intelligent technology
Brakes
Brake servo
The brake servo increases the pressure you apply to the brake pedal. It
works
only when the engine is running.
If the brake servo is not functioning due to a malfunction, or if the vehicle
has to be towed, you will have to press the brake pedal considerably harder
to make up for the lack of servo assistance.
WARNING
The braking distance can also be affected by external factors.
●
Never let the vehicle coast with the engine switched off. Failure to do
so could result in an accident. The braking distance is increased consid-
erably when the brake servo is not active.
●
If the brake servo is not working, for example when the vehicle is be-
ing towed, you will have to press the brake pedal considerably harder
than normal.
Hydraulic Brake Assist (HBA)*
The Hydraulic Brake Assist function (HBA) is only included in
vehicles with ESC (ESP).
In an emergency,
most drivers brake in time, but not with maximum force.
This results in unnecessarily long braking distances.
This is when the brake assist system comes into action. When pressing the
brake pedal rapidly, the assistant interprets it as an emergency. It then very
quickly builds up the full brake pressure so that the ABS can be activated
more quickly and efficiently, thus reducing the braking distance.
Do not reduce the pressure on the brake pedal. The brake assist system
switches off automatically as soon as you release the brake.
Emergency braking warning
If the vehicle is braked suddenly and continuously at a
speed of more than
80 km/h, the brake light flashes several times per second to warn vehicles
driving behind. If you continue braking, the hazard warning lights will come
on automatically when the vehicle comes to a standstill. They switch off au-
tomatically when the vehicle starts to move again.
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Intelligent technology
WARNING
●
The risk of accident is higher if you drive too fast, if you do not keep
your distance to the vehicle in front, and when the road surface is slip-
pery or wet. The increased accident risk cannot be reduced by the brake
assist system.
●
The brake assist system cannot defy the laws of physics. Slippery
and wet roads are dangerous even with the brake assist system! There-
fore, it is essential that you adjust your speed to suit the road and traffic
conditions. Do not let the extra safety features tempt you into taking any
risks when driving.
Anti-lock brake system and traction control
M-ABS (ABS and ASR (TCS))
Anti-lock brake system (ABS)
The anti-lock brake system prevents the wheels locking dur-
ing braking.
The anti-lock brake system (ABS) is an important part of the vehicle's active
safety system.
How the ABS works
If one of the wheels is turns too slowly in relation to the road speed, and is
close to locking, the system will reduce the braking pressure for this wheel.
The driver is made aware of this control process by a
pulsating of the brake
pedal and audible noise. This is a deliberate warning to the driver that one
or more of the wheels is tending to lock and the ABS control function has
intervened. In this situation it is important to keep
the brake pedal fully de-
pressed so the ABS can regulate the brake application. Do not “pump”.
If you brake hard on a slippery road surface, the best possible control is re-
tained as the wheels do not lock.
However, ABS will not necessarily guarantee shorter braking distances in
all
conditions. The braking distance could even be longer if you brake on gravel
or on fresh snow covering 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 features tempt you into taking any risks when driving.
●
The effectiveness of ABS is also determined by the tyres fitted
⇒
page 233.
●
If the running gear or brakes are modified, the effectiveness of the
ABS could be severely limited.
Traction control system ASR (TCS)
The traction control system prevents the drive wheels from
spinning when the vehicle is accelerating.
Description and operation of the traction control system during
acceleration ASR (TCS)
ASR (TCS) reduces engine power to help prevent the drive wheels of front-
wheel drive vehicles losing traction during acceleration. The system works
in the entire speed range in conjunction with ABS.
If a malfunction should
occur in the ABS, the ASR (TCS) will also stop working.
The ASR (TCS) helps the vehicle to start moving, accelerate and climb a gra-
dient in slippery conditions where this may otherwise be difficult or even
impossible.
Safety First
Operating Instructions
Practical Tips
Technical Specifications
