Braking intervention
If the system detects that the driver is braking insuf-
ficiently when there is a risk of collision, the system
can increase the braking force and help prevent
a collision. The braking intervention takes place only
for as long as the brake pedal is pressed hard.
City Emergency Braking System
The City Emergency Braking System is part of Front
Assist. If the driver does not react to a possible colli-
sion, the system can also automatically brake the
vehicle with increasing braking force without any
advance warning.
The red warning lamp
lights up in this case.
Distance warning
The system detects when safety is
endangered by driving too close to
the vehicle in front. The indicator
lamp lights up. Increase the distance.
Speed range: approx. 65 km/h (40 mph) to 210 km/h
(130 mph).
Limits of Front Assist
Please refer to
at the start of the chapter on
page 165.
Front Assist has physical and system-related limita-
tions. You should therefore always be prepared to
take full control of the vehicle if necessary.
Delayed response
If the radar sensor is exposed to environmental con-
ditions that impair sensor functioning, the system
may detect this only after a certain delay. For this
reason, any restrictions to functions may be dis-
played only after a delay at the start of the journey
and when driving → page 165.
Objects that cannot be detected
Front Assist may not react or may react with a delay
or provide with an unwanted response in the follow-
ing situations:
— Vehicles that are driving outside the sensor range
in close proximity to your vehicle, e.g. vehicles
that are driving offset to your vehicle or motor-
bikes.
— Vehicles that change into your lane directly in
front of your vehicle.
— Vehicles with bodies or attachments that project
beyond the vehicle.
— Oncoming vehicles or vehicles crossing your path.
— Pedestrians who are standing still or coming to-
wards the vehicle.
Function limitations
Front Assist may not react or may react with a delay
or provide with an unwanted response in the follow-
ing situations:
— In tight bends.
— Driving in heavy rain, snow or heavy spray.
— Driving in multi-storey car parks and tunnels.
— Driving on roads with embedded metal objects,
e.g. railway tracks.
— Reversing.
— If ESC is taking corrective action.
— If the
Offroad
driving profile mode is switched on
(depending on equipment).
— If ESC Sport (depending on equipment) is on
→ page 195.
— If the radar sensor is dirty or covered.
— If several brake lights on the vehicle are faulty.
— If there is a fault in several brake lights on a trailer
with an electrical connection to the vehicle.
— If the vehicle accelerates hard or the accelerator
is fully depressed.
— In complex driving situations, e.g. at traffic is-
lands.
— In unclear traffic situations, e.g. vehicles ahead
are braking heavily or turning off.
— If there is a fault in Front Assist.
Switching off Front Assist
Front Assist is not suitable for use in the following
situations due to the limitations of the system and
must be switched off →
:
— If the vehicle is utilised in a capacity beyond us-
age on public roads, e.g. off-road or on a race
track.
Area monitoring system
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