Driving safety systems
Driving safety systems overview
In this section, you will find information about
the following driving safety systems:
R ABS (Anti-lock BrakingSystem)
(Y page 68)
R BAS (Brake AssistSystem) (Y page 69)
R Active Brake Assist (Y page 69)
R Adaptive brake lights (Y page 71)
R ESP ®
(E lectronic StabilityProgram)
(Y page 72)
R EBD (electronic brake forcedistribution)
(Y page 75)
R ADAPTIVE BRAKE (Y page 75)
R STEER CONTROL (Y page 75)Important safety notes
If you fail to adapt your driving style or if you are
inattentive, the driving safety systems can nei-
ther reduce the risk of an accident nor override
the laws of physics. Driving safety systems are
merely aids designed to assist driving. You are
responsible for maintaining the distance to the
vehicle in front, for vehicle speed, for braking in
good time, and for staying in lane. Always adapt your driving style to suit the prevailing road and weather conditions and maintain a safe distance
from the vehicle in front. Drive carefully.
The driving safety systems described work as
effectively as possible only when there is ade-
quate contact between the tyres and the road
surface. Please pay special attention to the
notes on tyres, recommended minimum tyre
tread depths etc. (Y page 335).
In wintry driving conditions, always use winter
tyres (M+S tyres) and, if necessary, snow
chains. Only in this way will the driving safety
systems described in this section work as effec-
tively as possible. ABS (Anti-lock Braking System)
General information ABS regulates brake pressure in such a way that
the wheels do not lock when you brake. This
allows you to continue steering the vehicle when braking. The
! ABS warning lamp on the instrument
cluster lights up when the ignition is switched
on. It goes out when the engine is running.
ABS works from a speed of about 8 km/h,
regardless of road-surface conditions. ABS
works on slippery surfaces, even when you
brake only gently.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 68). G
WARNING
If ABS is faulty, the wheels could lock when
braking. The steerability and braking charac-
teristics may be severely impaired. Addition-
ally, further driving safety systems are deac-
tivated. There is an increased danger of skid- ding and accidents.
Drive on carefully. Have ABS checked imme-
diately at a qualified specialist workshop.
If ABS is malfunctioning, other systems, includ-
ing driving safety systems, will also become
inoperative. Observe the information on the ABS warning lamp (Y page 267) and display mes-
sages that may be shown on the instrument
cluster (Y page 235).
Brakes X
If ABS intervenes: continue to depress the
brake pedal with force until the braking sit-
uation is over.
X To make a full brake application: depress
the brake pedal with full force.
If ABS intervenes when braking, you will feel a
pulsing in the brake pedal.
The pulsating brake pedal can be an indication
of hazardous road conditions; this serves as a
reminder to take extra care while driving.
Off-road ABS An ABS system specifically suited to off-road
terrain is activated automatically once the off-
road program is activated (Y
page 192).
At speeds below 30 km/h, the front wheels lock
cyclically during braking. The digging-in effect
achieved in the process reduces the stopping 68
Driving safety syste
msSafety
Safety systems
Display messages
Possible causes/consequences and
M
MSolutions !÷
currently unavaila‐
currently unavaila‐
ble ble See
SeeOwner's
Owner's Man‐
Man‐
ual
ual ABS (Anti-lock Braking System), BAS (Brake Assist System), ESP
®
(Electronic Stability Program), ESP ®
trailer stabilisation, the HOLD
function, hill start assist and PRE-SAFE ®
are temporarily unavailable.
Adaptive brake lights and Active Brake Assist may have also failed.
In addition, the !,÷andå warning lamps may light up in
the instrument cluster.
ATTENTION ASSIST is deactivated.
Possible causes:
R self-diagnosis is not yet complete
R the on-board voltage may be insufficient
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you brake
hard, for example.
The steerability and braking characteristics may be severely affected. The braking distance may increase in an emergency braking situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased risk of skidding and/or accident.
X Carefully drive on a suitable stretch of road, making slight steering
movements, at a speed above 20 km/h.
If the display message disappears, the functions mentioned above
are available again.
If the multifunction display still shows the display message: X Drive on carefully.
X Consult a qualified specialist workshop immediately. !÷
inoperative inoperative See
See Own‐
Own‐
er's Manual
er's Manual ABS, BAS, ESP
®
, ESP ®
trailer stabilisation, the HOLD function, hill
start assist and PRE-SAFE ®
are unavailable due to a malfunction.
Adaptive brake lights and Active Brake Assist may have also failed.
The !, ÷,åandJ warning lamps may also light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you brake
hard, for example.
The steerability and braking characteristics may be severely affected. The braking distance may increase in an emergency braking situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased risk of skidding and/or accident.
X Drive on carefully.
X Consult a qualified specialist workshop immediately. Display messages
235On-board computer and displays Z
Display messages
Possible causes/consequences and
M
MSolutions ÷
currently unavaila‐ currently unavaila‐
ble ble
See
SeeOwner's
Owner's Man‐
Man‐
ual
ual ESP
®
, ESP ®
trailer stabilisation, BAS, the HOLD function, hill start
assist and PRE-SAFE ®
are temporarily unavailable.
Adaptive brake lights and Active Brake Assist may have also failed.
In addition, the ÷andå warning lamps may light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
The self-diagnosis function, for example, may not be complete.
G WARNING
The brake system continues to function normally, but without the
functions listed above.
The braking distance may thus increase in an emergency braking sit-
uation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased risk of skidding and/or accident.
X Carefully drive on a suitable stretch of road, making gentle steering
movements at speeds of above 20 km/h.
If the display message disappears, the functions mentioned above
are available again.
If the multifunction display still shows the display message:
X Drive on carefully.
X Consult a qualified specialist workshop immediately. ÷
inoperative inoperative
See
SeeOwn‐
Own‐
er's Manual
er's Manual ESP
®
, ESP ®
trailer stabilisation, BAS, the HOLD function, hill start
assist and PRE-SAFE ®
are unavailable due to a malfunction.
Adaptive brake lights and Active Brake Assist may have also failed.
In addition, the ÷andå warning lamps may light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above.
The braking distance may thus increase in an emergency braking sit-
uation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased risk of skidding and/or accident.
X Drive on carefully.
X Consult a qualified specialist workshop immediately. 236
Display
messagesOn-board computer and displays
Display messages
Possible causes/consequences and
M
MSolutions T
!
÷ inoperative
inoperative See
SeeOwn‐
Own‐
er's Manual
er's Manual EBD (electronic brake force distribution), ABS, BAS, ESP
®
, ESP ®
trailer
stabilisation, the HOLD function, hill start assist and PRE-SAFE ®
are
unavailable due to a malfunction.
Adaptive brake lights and Active Brake Assist may have also failed.
A warning tone sounds.
In addition, the ÷,åand! warning lamps may light up in
the instrument cluster.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear wheels could therefore lock
if you brake hard, for example.
The steerability and braking characteristics may be severely affected. The braking distance may increase in an emergency braking situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased risk of skidding and/or accident.
X Drive on carefully.
X Consult a qualified specialist workshop immediately. !
Turn on the igni‐ Turn on the igni‐
tion tion
to
torelease
release the
the
parking brake
parking brake The red
!indicator lamp lights up.
You have attempted to release the electric parking brake while the
ignition was switched off.
X Key: turn the key to position 1in the ignition lock.
X KEYLESS-GO: switch on the ignition. !
Release parking Release parking
brake brake The red
!indicator lamp flashes and a warning tone sounds. A
condition for automatic release of the electric parking brake is not
fulfilled (Y page 168).
You are driving with the electric parking brake applied.
X Release the electric parking brake manually. The red
!indicator lamp flashes and a warning tone sounds.
You are initiating emergency braking using the electric parking brake
(Y page 169). !
Parking brake See Parking brake See
Owner's Manual Owner's Manual The yellow
!warning lamp lights up.
The electric parking brake is malfunctioning.
To apply:
X Switch the ignition off.
X Press the electric parking brake handle for at least ten seconds.
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission to
position B.
X Consult a qualified specialist workshop. Display
messages
237On-board computer and displays Z
Display messages
Possible causes/consequences and
M
MSolutions Blind Spot Assist
Blind Spot Assist
currently unavaila‐ currently unavaila‐
ble ble
See
SeeOwner's
Owner's Man‐
Man‐
ual
ual Blind Spot Assist is temporarily inoperative.
Possible causes:
R the radar sensor system is temporarily inoperative, e.g. due to elec-
tromagnetic radiation emitted by nearby TV or radio stations or
other sources of electromagnetic radiation
R the radar sensor system is outside the operating temperature range
The yellow 9indicator lamps also light up in the exterior mirrors.
Once the causes listed above no longer apply, the display message
disappears.
Blind Spot Assist is operational again.
If the display message does not disappear:
X Stop the vehicle, paying attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 166).
X Restart the engine. Blind Spot Assist Blind Spot Assist
not available when not available when
towing a trailer towing a trailer
See Owner's Manual See Owner's Manual
. Blind Spot Assist is deactivated while towing a trailer.
You have established the electrical connection between the trailer and
your vehicle.
X Press aon the steering wheel to confirm the display message. Blind Spot Assist
Blind Spot Assist
inoperative inoperative Blind Spot Assist is malfunctioning.
The yellow
9indicator lamps also light up in the exterior mirrors.
X Consult a qualified specialist workshop. Parking Pilot can‐ Parking Pilot can‐
celled celled The driver's door is open and the driver's seat belt has not been fas-
tened.
X Repeat the parking process with the seat belt fastened and the
driver's door closed. You inadvertently touched the multifunction steering wheel while
steering intervention was active.
X While steering intervention is active, make sure not to touch the
multifunction steering wheel. The vehicle has started to skid and ESP
®
has intervened.
X Use Parking Pilot again later (Y page 196).Parking Pilot inop‐ Parking Pilot inop‐
erative erative You have just carried out a large number of turning or parking manoeu-
vres.
Parking Pilot will become available again after approximately ten
minutes (Y page 196).
X Stop the vehicle, paying attention to road and traffic conditions.
X Switch off and restart the engine.
If the multifunction display still shows the display message:
X Consult a qualified specialist workshop. Display
messages
253On-board computer and displays Z
Display messages
Possible causes/consequences and
M
MSolutions Distance Pilot pas‐
Distance Pilot pas‐
sive sive You have depressed the accelerator pedal. Distance Pilot DISTRONIC
is no longer controlling the speed of the vehicle.
X Remove your foot from the accelerator pedal. Distance Pilot
Distance Pilot
- - - km/h - - - km/h A condition for activating Distance Pilot DISTRONIC has not been met.
X Check the activation conditions for Distance Pilot DISTRONIC
(Y page 182). Distance Pilot and Distance Pilot and
Limiter inoperative Limiter inoperative Distance Pilot DISTRONIC and speed limiter are faulty. A warning tone
also sounds.
X Consult a qualified specialist workshop. Cruise control and Cruise control and
Limiter inoperative Limiter inoperative Cruise control and speed limiter are faulty.
A warning tone also sounds.
X Consult a qualified specialist workshop. Limiter passive
Limiter passive If you depress the accelerator pedal beyond the pressure point (kick-
down), the limiter is switched to passive mode.
The speed limitation is not active.
X Drive slower than the stored speed and without kickdown.
X Call up the last speed stored again.
or X Set a new speed.
When the display message disappears, the speed limitation is active. Cruise control Cruise control
- - - km/h - - - km/h R
A condition for activating cruise control has not been met.
You have tried to store a speed below 30 km/h, for example.
R ESP ®
is deactivated. The yellow ESP ®
OFF warning lamp is lit.
X If conditions permit, drive at a speed greater than 30 km/h and
store the speed.
or X Check the activation conditions for cruise control (Y page 177).
or
X Reactivate ESP ®
(Y page 227). 120 km/h! 120 km/h!
Maximum Maximum
speed
speedexcee‐
excee‐
ded
ded For certain countries only: the maximum speed has been exceeded.
In addition, the multifunction display shows 120 km/h!
120 km/h!.
X Drive more slowly. Display
messages
255On-board computer and displays Z
Tyres
Display messages
Possible causes/consequences and
M
MSolutions Tyre
Tyre
pressure
pressure Check
Check
tyre(s)
tyre(s) The tyre pressure loss warning system has detected a significant loss
in pressure.
A warning tone also sounds.
Possible cause:
R you have changed the positions of the wheels and tyres or fitted new
wheels and tyres
R the tyre pressure in one or more tyres has dropped
G WARNING
Underinflated tyres pose the following risks:
R the tyres may burst, especially as the load and vehicle speed
increase
R the tyres may wear excessively and/or unevenly, which may greatly
impair tyre traction
R the driving characteristics, as well as steering and braking, may be
greatly impaired
There is a risk of an accident.
X Stop the vehicle without making any sudden steering or braking
manoeuvres. Pay attention to the traffic conditions as you do so.
X Secure the vehicle against rolling away (Y page 166).
X Check the tyres and, if necessary, follow the instructions for a flat
tyre (Y page 317).
X Check and, if necessary, correct the tyre pressures.
X Restart the tyre pressure loss warning system when the tyre pres-
sure is correct (Y page 339). Check tyre pres‐ Check tyre pres‐
sures then restart sures then restart
Run Flat Indicator Run Flat Indicator The tyre pressure loss warning system generated a display message
and has not been restarted since.
X Set the correct tyre pressure in all four tyres.
X Restart the tyre pressure loss warning system (Y page 339).Run Flat Indicator Run Flat Indicator
inoperative inoperative The tyre pressure loss warning system is faulty.
X Consult a qualified specialist workshop. Rectify tyre pres‐
Rectify tyre pres‐
sure sure The tyre pressure is too low in at least one of the tyres, or the tyre
pressure difference between the wheels is too great.
X Check the tyre pressures at the next opportunity (Y page 340).
X If necessary, correct the tyre pressure.
X Restart the tyre pressure monitor (Y page 341).256
Display
messagesOn-board computer and displays