Driver assistance systems
Lane Assist* Intr oduction The Lane Assist System helps the driver
st
ay in his/her l
ane within the physical lim-
its of the system. This function is not suita-
ble and is not designed to keep the vehicle
automatically in the lane.
Using the camera located in the windscreen,
the Lane Assist system detects the limits (lane
lines) dividing the lanes in which the vehicle is
travelling. If the vehicle gets too close to the
detected lane limits, the system alerts the
driver through a corrective motion of the
steering wheel. The driver can cancel the
steering corrective action at any time.
No warning is produced with the turn signals
activated, given that the Lane Assist system
understands that a lane change is required.
System limits
Use the Lane Assist system only on large,
well-maintained motorways and highways.
The system is not available under the follow-
ing conditions:
Driving
Note
If the lane departure warning with rear
cr oss tr
affic alert does not work as descri-
bed in this chapter, stop using it and con-
tact a specialised workshop. Control lamp
Fig. 188
Control lamp of the lane departure
w arning. Fig. 189
Control lamp of the lane departure
w arning. It lights up
It turns on once briefly: the lane departure warning is
activ at
ed and ready to operate, i.e. when activating
the system.
It lights up continuously: the lane departure warning
has det ect
ed a vehicle in the blind spot. Flashes
A vehicle has been detected in the adjacent lane and
the t urn signal has been engaged in the dir
ection of
the detected vehicle
Braking and parking
Brake assist systems Electronic Stability Control (ESC)
The ESC helps t
o impr
ove safety. It reduces
the tendency to skid and improves the stabili-
ty and roadholding of the vehicle. The ESC
detects critical handling situations, such as
vehicle understeer or oversteer, or wheelspin
on the driving wheels. It stabilises the vehicle
by braking individual wheels or by reducing
the engine torque. The warning lamp will
flash on the instrument panel when the ESC is
intervening !.
The ESC includes the anti-lock brake system
(ABS), the hydraulic brake assist (HBA), the
traction control system (TCS), electronic dif-
ferential lock (EDS), electronic torque control
(XDS) and the tractor-trailer sway mitiga-
tion*.
ESC also helps stabilise the vehicle by
changing the torque.
The TCS can be deactivated when wheel
spin is desirable ››› page 281
.
Anti-lock brake system (ABS)
ABS prevents the wheels from locking up un-
der braking until the vehicle has reached a
virtual standstill. You can continue to steer the
vehicle even when the brakes are on full.
Keep your foot on the brake pedal and do not
pump the brakes. You will feel the brake pedal
pulsate while the ABS is working. If the running gear or brake system is modi-
fied, the eff
ectiv
eness of the ABS could be se-
verely limited.
Hydraulic Brake Assist (HBA)
The brake assist system can reduce the re-
quired braking distance. The braking force is
automatically boosted if you press the brake
pedal quickly in an emergency. You must
keep pressing the brake pedal until the dan-
ger has passed.
Traction control (TCS)
In the event of the wheels spinning, the TCS
reduces the engine torque to adapt to the
road condition. This helps the car to start
moving, accelerate or climb a gradient.
Electronic differential lock (EDL)
When the EDL detects wheelspin, it brakes
the spinning wheel and directs the power to
the other driven wheel. This function is active
up to approximately 100 km/h (62 mph).
To prevent the disc brake of the braked wheel
from overheating, the EDL cuts out automati-
cally if subjected to excessive loads. The ve-
hicle can still be driven. The EDL will switch on
again automatically when the brake has
cooled down. Tractor-trailer sway mitigation*
If the vehicl
e is pulling a trailer, it will control
the following: tractor-trailers tend to sway.
When the swaying of the trailer is felt by the
vehicle and detected by the ESC, it will auto-
matically brake the towing vehicle within the
limits of the system and mitigate the sway.
Tractor-trailer sway mitigation is not available
in all countries ››› page 303
.
Electronic engine torque management
(XDS)
When taking a curve, the driveshaft differen-
tial allows the outer wheel to turn at a higher
speed than the inner wheel. In this way, the
wheel that is turning faster (outer wheel) re-
ceives 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 can
cause a loss of grip on the drive axle, in this
case the front axle, which results in under-
steer or “lengthening” of the trajectory.
The XDS can detect and correct this effect
via the sensors and signals of the ESC.
Via the ESC, the XDS will brake the inside
wheel and counter the excess driving torque
of that wheel. This means that the requested
trajectory is much more precise. »
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