
Display messages
Possible causes/consequences and
M
MSolutions b
Reversing light Reversing light The reversing lamp is faulty.
X Check whether you are permitted to replace the bulb yourself
(Y page 111).
or
X Consult a qualified specialist workshop. b
Left tail lamp Left tail lamp
or
Right tail lamp
Right tail lamp The left or right-hand tail lamp is faulty.
X Consult a qualified specialist workshop. b
Left daytime driv‐ Left daytime driv‐
ing lamp ing lamp
orRight
Right
daytime
daytime driving
drivinglamp
lamp The left or right-hand daytime driving lamp is faulty.
X Check whether you are permitted to replace the bulb yourself
(Y page 111).
or
X Consult a qualified specialist workshop. b
Malfunction Malfunction
See
SeeOwn‐
Own‐
er's Manual
er's Manual The exterior lighting is faulty.
X Consult a qualified specialist workshop. Vehicles with trailer tow hitch: a fuse may have blown.
X Stop the vehicle, paying attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 155).
X Check the fuses (Y page 308).
X If necessary, replace the blown fuse. Observe the warning notes as
you do so.
If the multifunction display still shows the display message: X Consult a qualified specialist workshop. b
AUTO lights inoper‐ AUTO lights inoper‐
ative ative The light sensor is faulty.
X
Consult a qualified specialist workshop. b
Switch off lights Switch off lights The lights are still switched on when you leave the vehicle. A warning
tone also sounds.
X Turn the light switch to the Ãposition. b
Switch on headlamps Switch on headlamps You are driving without dipped-beam headlamps.
X
Turn the light switch to the Lorà position. 230
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions Lane
Lane
Keeping
Keeping Assist
Assist
currently unavaila‐
currently unavaila‐
ble ble See
SeeOwner's
Owner's Man‐
Man‐
ual
ual Lane Keeping Assist is deactivated and temporarily inoperative.
Possible causes:
R The windscreen is dirty in the camera's field of vision.
R Visibility is impaired due to heavy rain, snow or fog.
R There have been no lane markings for an extended period.
R the lane markings are worn, dark or covered, e.g. by dirt or snow
Once the causes listed above no longer apply, the display message
goes out.
Lane Keeping Assist is operational again.
If the display message does not disappear:
X Stop the vehicle, paying attention to road and traffic conditions.
X Safeguard the vehicle against rolling away (Y page 155).
X Clean the windscreen. Lane Lane
Keeping
Keeping Assist
Assist
inoperative
inoperative Lane Keeping Assist is faulty.
X Consult a qualified specialist workshop. 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
electromagnetic 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
goes out.
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 155).
X Restart the engine. Active Blind Spot Active Blind Spot
Assist not availa‐ Assist not availa‐
ble when towing a ble when towing a
trailer trailer
See
SeeOwner's
Owner's
Manual
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. Display
messages
235On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions Ð
Steering malfunc‐ Steering malfunc‐
tion See Owner's tion See Owner's
Manual Manual The electric steering lock is malfunctioning.
G WARNING
The steering may be locked by the electric steering lock.
There is a risk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 155).
X Do not drive on.
X Consult a qualified specialist workshop. _
Before Before
starting
starting the
the
engine, turn the
engine, turn the
steering wheel. steering wheel. The electric steering lock was unable to unlock the steering.
X Remove the key from the ignition lock.
X To unlock the steering, move the steering wheel slightly.
X Insert the key into the ignition lock again. Telephone
Telephone
No
Noservice
service Your vehicle is outside the mobile phone network provider's trans-
mitter/receiver range.
X Wait until the mobile phone operational readiness symbol appears
in the multifunction display. ¥
Top up washer fluid Top up washer fluid The washer fluid level in the washer fluid reservoir has dropped below
the minimum.
X Top up the washer fluid (Y page 284).Wiper malfunction‐
Wiper malfunction‐
ing ing The windscreen wipers are defective.
X Consult a qualified specialist workshop. Hazard warning
Hazard warning
lamps malfunction‐ lamps malfunction‐
ing ing The hazard warning lamps are faulty.
X Consult a qualified specialist workshop. Key
Display messages
Possible causes/consequences and
M
MSolutions Â
Key Key
does
does not
notbelong
belong
to vehicle
to vehicle You have put the wrong key in the ignition lock.
X Use the correct key. Â
Replace key Replace key The key needs to be replaced.
X Consult a qualified specialist workshop. Â
Change Change
key
keybatteries
batteries The key battery is discharged.
X Change the battery(Y page 79).246
Display
messagesOn-board computer and displays

Safety
Seat belts Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions ü
N
Only for certain countries: the red seat belt warning lamp lights up for 6 seconds
after the engine starts.
The seat belt warning lamp reminds the driver and front passenger to fasten their
seat belts.
X Fasten your seat belt (Y page 43).ü
N
Only for certain countries: the red seat belt warning lamp lights up after the
engine starts. In addition, a warning tone sounds for up to 6 seconds.
The driver's seat belt is not fastened.
X Fasten your seat belt (Y page 43).
The warning tone ceases. ü
N
The red seat belt warning lamp lights up after the engine starts, as soon as the
driver's or the front-passenger door is closed.
The driver or passenger has not fastened their seat belt.
X Fasten your seat belt (Y page 43).
The warning lamp goes out.
There are objects on the front-passenger seat.
X Remove the objects from the front-passenger seat and stow them in a secure
place.
The warning lamp goes out. ü
N
The red seat belt warning lamp flashes and an intermittent audible warning
sounds.
The driver or passenger has not fastened their seat belt. At the same time, you are
driving faster than 25 km/h or have briefly driven faster than 25 km/h.
X Fasten your seat belt (Y page 43).
The warning lamp goes out and the intermittent warning tone ceases.
There are objects on the front-passenger seat. At the same time, you are driving
faster than 25 km/h or have briefly driven faster than 25 km/h.
X Remove the objects from the front-passenger seat and stow them in a secure
place.
The warning lamp goes out and the intermittent warning tone ceases. 248
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Safety systems
Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions J
N
The red brake system warning lamp lights up while the engine is running. A
warning tone also sounds.
G WARNING
The brake boosting effect is malfunctioning and the braking characteristics may be
affected.
There is a risk of an accident.
X Stop the vehicle immediately, paying attention to road and traffic conditions. Do
not continue driving.
X Secure the vehicle against rolling away (Y page 155).
X Consult a qualified specialist workshop.
X Observe the additional display messages in the multifunction display. J
N
The red brake system warning lamp lights up while the engine is running. A
warning tone also sounds.
There is insufficient brake fluid in the brake fluid reservoir.
G WARNING
Braking efficiency may be impaired.
There is a risk of an accident.
X Stop the vehicle immediately, paying attention to road and traffic conditions. Do
not continue driving.
X Secure the vehicle against rolling away (Y page 155).
X Do not top up the brake fluid. Topping up will not correct the fault.
X Consult a qualified specialist workshop.
X Observe the additional display messages in the multifunction display. Warning and indicator lamps in the instrument cluster
249On-board computer and displays Z

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
M Solutions !
N
The yellow ABS warning lamp lights up while the engine is running.
ABS (Anti-lock Braking System) has been deactivated due to a fault. BAS (Brake
Assist), Active Brake Assist, ESP ®
(Electronic Stability Program), ESP ®
trailer sta-
bilisation, the HOLD function, hill start assist, the adaptive brake lights and
PRE‑SAFE ®
are also deactivated, for example.
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 impaired as a result. The braking distance may increase in an emergency braking situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
Increased risk of skidding and/or 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 unavailable. 250
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions !
N
The yellow ABS warning lamp lights up while the engine is running.
ABS is temporarily unavailable. BAS, Active Brake Assist, ESP ®
, ESP ®
trailer sta-
bilisation, EBD (Electronic Brake-force Distribution), the HOLD function, hill start
assist, the adaptive brake lights and PRE ‑SAFE®
, for example, are also deactivated.
Possible causes:
R Self-diagnosis is not yet complete.
R The on-board voltage may be insufficient.
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 if you brake hard, for exam-
ple.
The steerability and braking characteristics may be severely impaired as a result. The braking distance may increase in an emergency braking situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is a risk of an accident.
X Carefully drive on a suitable stretch of road, making slight steering movements
at a speed above 20 km/h.
The functions mentioned above are available again when the warning lamp goes out.
If the warning lamp is still on: X Observe the additional display messages in the multifunction display.
X Drive on carefully.
X Consult a qualified specialist workshop immediately. !
N
The yellow ABS warning lamp lights up while the engine is running. A warning
tone also sounds.
EBD is faulty. ABS, BAS, Active Brake Assist, ESP ®
, ESP ®
trailer stabilisation, the
HOLD function, hill start assist, the adaptive brake lights and PRE‑SAFE ®
, for
example, 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 if you brake hard, for exam-
ple.
The steerability and braking characteristics may be severely impaired as a result. The braking distance may increase in an emergency braking situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
Increased risk of skidding and/or accident!
X Observe the additional display messages in the multifunction display.
X Drive on carefully.
X Consult a qualified specialist workshop immediately. Warning and indicator lamps in the instrument cluster
251On-board computer and displays Z

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
M Solutions !
֌
J
N
The red brake system warning lamp and the yellow ABS, ESP ®
and ESP ®
OFF
warning lamps are lit while the drive system is running.
ABS and ESP ®
are malfunctioning. BAS, Active Brake Assist, EBD, PRE ‑SAFE®
, the
HOLD function, hill start assist, the adaptive brake lights and ESP ®
trailer stabili-
sation, for example, 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 if you brake hard, for exam-
ple.
The steerability and braking characteristics may be severely impaired as a result. The braking distance may increase in an emergency braking situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
Increased risk of skidding and/or accident!
X Observe the additional display messages in the multifunction display.
X Drive on carefully.
X Consult a qualified specialist workshop immediately. ÷
N
The yellow ESP ®
warning lamp flashes while the vehicle is in motion.
ESP ®
or traction control has engaged due to a risk of skidding or because at least
one wheel has started to spin.
Cruise control or Distance Pilot DISTRONIC is deactivated.
X Only depress the accelerator pedal as far as necessary when pulling away.
X Accelerate more gently while the vehicle is in motion.
X Adapt your driving style to suit the road and weather conditions.
X Do not deactivate ESP ®
.
In exceptional cases (Y page 71) it may be better to deactivate ESP ®
.
Observe the important safety notes on ESP ®
(Y page 70). 252
Warning and indicator lamps in the instrument clusterOn-board computer and displays