
A requirement for the display of the contents
is that the following functions are available in the vehicle and are switched on:
R Cruise control and SPEEDTRONIC
R DISTRONIC PLUS
R Traffic Sign Assist
R Navigation
The head-up display allows the driver to see
all of the information without having to take
their eyes off the road.
Important safety notes The head-up display is only an aid and is not a
substitute for attentive driving.
Speed limits and overtaking restrictions are
not always correctly displayed. Traffic signs
always have priority over the Traffic Sign
Assist display.
The visibility of the head-up display is influ-
enced by the following conditions:
R the driver's seat position
R the positioning of the display image
R the general light conditions
R sunglasses with polarisation filters
R Wet road surfaces
R blocking of sunlight by objects on the dis-
play cover
In the event of extreme sunlight, sections of
the display may fade. This can be reversed by
switching the head-up display off and on
again.
i Vehicles with the head-up display are
equipped with a special windscreen.
Should repairs be necessary, have the
windscreen replaced at a qualified special-
ist workshop. Displays and operation Switching the head-up display on/off
X
Press button :.
When the head-up display is switched on,
the display appears in the driver's field of
vision. 316
Displays and operationOn-board computer and displays

X
Confirm by pressing aon the steering
wheel.
X Press :or9 to select the Head-up
Head-up
display
display submenu.
X Press ato confirm.
X Select Display content
Display content with: or
9.
X Press ato confirm.
A graphic selection list appears.
X Press :or9 to select the desired
display.
X Press the abutton to confirm the selec-
tion.
Further information on navigation can be
found in the separate Audio 20 or COMAND
Online operating instructions.
Further information about Traffic Sign Assist
(Y page 274).
Setting the position
You can adjust the position of the head-up
display on the windscreen. You can compen-
sate for height differences if the seat posi-
tions are changed, for example.
X Switch on the head-up display
(Y page 316).
X Press òon the steering wheel to open
the menu list.
X Press :or9 on the steering wheel
to select the Settings
Settings menu.
X Confirm by pressing aon the steering
wheel.
X Use : or9 to select the Head-up
Head-up
display
display submenu.
X Press ato confirm.
X Using :or9, select the Position Position
function.
X Press ato save the setting.
X Press :or9 to adjust the position
to a level from Level +5
Level +5toLevel -5
Level -5.
X Press aor% to save the setting.
Using the Memory function, you can save and call up the set position of the head-up display
as a single memory preset (Y page 134).Adjusting the brightness
The brightness of the head-up display is auto-
matically adjusted to the surrounding light
conditions. You can also individually adjust
the brightness of the head-up display.
X Switch on the head-up display
(Y page 316).
X Press òon the steering wheel to open
the menu list.
X Press :or9 on the steering wheel
to select the Settings
Settings menu.
X Confirm by pressing aon the steering
wheel.
X Use : or9 to select the Head-up
Head-up
display display submenu.
X Press ato confirm.
X Using :or9, select the Bright‐
Bright‐
ness
ness function.
X Press the abutton to save the setting.
X Press :or9 to adjust the bright-
ness to a level from Level +5
Level +5(bright) to
Level -5
Level -5 (dark).
X Press the aor% button to save the
setting.
Light submenu Switching the Intelligent Light System
on/off
X Press òon the steering wheel to open
the menu list.
X Press :or9 on the steering wheel
to select the Settings Settingsmenu.
X Confirm by pressing aon the steering
wheel.
X Press :or9 to select the Lights Lights
submenu.
X Press ato confirm.
X Using :or9, select the Intelli‐ Intelli‐
gent Light System
gent Light System function.
If the Intelligent Light System Intelligent Light System func-
tion has been switched on, the cone of light Menus and submenus
331On-board computer and displays Z

Safety systems
Display messages
Possible causes/consequences and
M
MSolutions !÷
currently unavail‐ currently unavail‐
able See Owner's able See Owner's
Manual Manual ABS (Anti-lock Braking System), ESP
®
(Electronic Stability Pro-
gram), BAS (Brake Assist), PRE‑SAFE ®
, HOLD function, hill start
assist, ESP ®
trailer stabilisation, Crosswind Assist, adaptive brake
lights, STEER CONTROL, Active Lane Keeping Assist and Active
Blind Spot Assist are temporarily unavailable.
BAS PLUS with Cross-Traffic Assist, PRE‑SAFE ®
Brake, PRE‑ SAFE®
PLUS and COLLISION PREVENTION ASSIST PLUS may also have
failed.
In addition, the ÷and! warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
For example, 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 affec-ted. 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 danger of skidding and risk of an accident.
X Drive on carefully.
Carefully drive on a suitable stretch of road, making slight steer-
ing 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 See inoperative See
Owner's Manual Owner's Manual ABS, ESP
®
, BAS, PRE‑SAFE ®
, HOLD function, hill start assist,
ESP ®
trailer stabilisation, Crosswind Assist, adaptive brake lights,
STEER CONTROL, Active Lane Keeping Assist and Active Blind
Spot Assist are unavailable due to a malfunction.
BAS PLUS with Cross-Traffic Assist, PRE‑SAFE ®
Brake, PRE‑SAFE ®
PLUS and COLLISION PREVENTION ASSIST PLUS may also have
failed.
In addition, the J,÷and! warning lamps may light up
in the instrument cluster. 336
Display messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions 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 affec- ted. 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 danger of skidding and risk of an accident.
X Drive on carefully.
X Consult a qualified specialist workshop immediately. ÷
inoperative See inoperative See
Owner's Manual Owner's Manual ESP
®
, BAS, PRE ‑SAFE®
, HOLD function, hill start assist,
ESP ®
trailer stabilisation, Crosswind Assist, adaptive brake lights,
STEER CONTROL, Active Lane Keeping Assist and Active Blind
Spot Assist are unavailable due to a malfunction.
BAS PLUS with Cross-Traffic Assist, PRE‑ SAFE®
Brake, PRE ‑SAFE®
PLUS and COLLISION PREVENTION ASSIST PLUS may also have
failed.
The ÷ warning lamp also lights 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
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Consult a qualified specialist workshop immediately. Display
messages
337On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions ÷
currently unavail‐ currently unavail‐
able See Owner's able See Owner's
Manual Manual ESP
®
, BAS, PRE ‑SAFE®
, HOLD function, hill start assist,
ESP ®
trailer stabilisation, Crosswind Assist, adaptive brake lights,
STEER CONTROL, Active Lane Keeping Assist and Active Blind
Spot Assist are unavailable due to a malfunction.
BAS PLUS with Cross-Traffic Assist, PRE‑ SAFE®
Brake, PRE ‑SAFE®
PLUS and COLLISION PREVENTION ASSIST PLUS may also have
failed.
The ÷ warning lamp also lights up in the instrument cluster.
The self-diagnosis function, for example, may not be complete.
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 braking distance may thus increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Carefully drive on a suitable stretch of road, making slight steer-
ing 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. 338
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions T!
÷
inoperative See inoperative See
Owner's Manual Owner's Manual EBD (electronic brake force distribution), ABS, ESP
®
, BAS,
PRE ‑SAFE ®
, HOLD function, hill start assist, ESP ®
trailer stabili-
sation, Crosswind Assist, adaptive brake lights, STEER CONTROL, Active Lane Keeping Assist and Active Blind Spot Assist are
unavailable due to a malfunction.
BAS PLUS with Cross-Traffic Assist, PRE‑ SAFE®
Brake, PRE ‑SAFE®
PLUS and COLLISION PREVENTION ASSIST PLUS may also have
failed.
In addition, the ÷and! warning lamps light up in the
instrument cluster and a warning tone sounds.
G WARNING
The brake system continues to function normally, but without the functions listed above. The front and rear wheels could therefore
lock, for example, if you brake hard.
The steerability and braking characteristics may be severely affec-ted. 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 danger of skidding and risk of an accident.
X Drive on carefully.
X Consult a qualified specialist workshop immediately. !
Turn on the igni‐ Turn on the igni‐
tion to release tion to release
the parking brake the parking brake The red
!indicator lamp lights up.
You attempted to release the electric parking brake while the igni-
tion was switched off.
X Switch the ignition on. !
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 220).
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 making an emergency stop using the electric parking
brake (Y page 220). Display
messages
339On-board computer and displays Z

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions !
N
The yellow ABS warning lamp is lit while the engine is running.
PLUG-IN HYBRID vehicles: the yellow ABS warning lamp is shown in the READY
driving status.
ABS (Anti-lock Braking System) has been deactivated due to a fault. Therefore BAS (Brake Assist System), BAS PLUS with Cross-Traffic Assist, COLLISION
PREVENTION ASSIST PLUS, ESP ®
(Electronic Stability Program), PRE‑SAFE ®
,
PRE‑SAFE ®
PLUS, PRE‑SAFE ®
Brake, the HOLD function, Hill Start Assist,
ESP ®
trailer stabilisation, Crosswind Assist, adaptive brake lights, STEER
CONTROL, Active Lane Keeping Assist and Active Blind Spot Assist are also
deactivated.
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 danger of skidding and risk of an accident.
X Observe the additional display messages in the multifunction display.
X Drive on carefully.
X Consult a qualified specialist workshop immediately.
If the ABS control unit is faulty, there is also a possibility that other systems,
such as the navigation system or the automatic transmission, will be unavail- able. Warning and indicator lamps in the instrument cluster
379On-board computer and displays Z

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions !
N
The yellow ABS warning lamp is lit while the engine is running.
PLUG-IN HYBRID vehicles: the yellow ABS warning lamp is shown in the READY
driving status.
A warning tone also sounds.
EBD is unavailable due to a malfunction. Therefore ABS, BAS, BAS PLUS with
Cross-Traffic Assist, COLLISION PREVENTION ASSIST PLUS, ESP ®
,
PRE‑ SAFE ®
, PRE‑SAFE ®
PLUS, PRE‑ SAFE®
Brake, the HOLD function, Hill Start
Assist, ESP ®
trailer stabilisation, Crosswind Assist, adaptive brake lights,
STEER CONTROL, Active Lane Keeping Assist and Active Blind Spot Assist are
also unavailable.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions
listed above. The front and rear wheels could therefore lock, for example, if you
brake hard.
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 danger of skidding and risk of an accident.
X Observe the additional display messages in the multifunction display.
X Drive on carefully.
X Consult a qualified specialist workshop immediately. 380
Warning and indicator lamps in the instrument clusterOn-board computer and displays