
Display messages Possible causes/consequences and
M Solutions
Lane Keeping
Assist inopera‐
tive or
Active Lane Keeping
Assist inoperative Lane Keeping Assis
torActive Lane Keeping Assist is faulty.
X Visit a qualified specialist workshop. Lane Keeping
Assist currently
unavailable See
Owner's Manual or
Active Lane Keep‐ ing Assist cur‐
rently unavailable
See Owner's Manual Blind Spot Assist or Active Blind Spot Assist is temporarily inop-
erative.
You have established the electrical connection between the trailer
and your vehicle.
X Press aon the steering wheel to confirm the display mes-
sage.
Blind Spot Assist or Active Blind Spot Assist is deactivated while
towing a trailer. Blind Spot Assist or Active Blind Spot Assist is temporarily inop-
erative .Possible causes:
R the sensors are dirty.
R the function is impaired due to heavy rain or snow.
R the radar sensor system is outside the operating temperature
range.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation.
The yellow 9indicator lamps also light up in the exterior mir-
rors.
Once the causes listed above no longer apply, the display message
goes out.
Blind Spot Assist or Active Blind Spot Assist is operational again.
If the display message does not disappear:
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 183).
X Clean the sensors (Y page 354).
X Restart the engine. Blind Spot Assist
inoperative or
Active Blind Spot Assist inoperative Blind Spot Assist or Active Blind Spot Assist is faulty.
The yellow 9indicator lamps also light up in the exterior mir-
rors.
X Visit a qualified specialist workshop. Display messages
285On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
DISTRONIC PLUS cur‐
rently unavailable
See Owner's Manual DISTRONIC PLU
Sis temporarily inoperative. Possible causes:
R the function is impaired due to heavy rain or snow.
R the sensors in the radiator trim and in the bumpers are dirty.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
Aw arning tone also sounds.
Once the causes listed abov eno longer apply, the display message
goes out.
DISTRONIC is operational again.
If the display message does not disappear:
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 183).
X Clean the sensors in the radiator trim and in the bumpers
(Y page 354).
X Restart the engine. DISTRONIC PLUS
inoperative DISTRONIC PLUS is faulty.
BAS PLUS and PRE-SAFE
®
Brake may also have failed.
Aw arning tone also sounds.
X Visi taqualified specialist workshop. DISTRONIC PLUS
inactive You have depressed the accelerator pedal. DISTRONIC PLUS is no
longer controlling the speed of the vehicle.
X
Remove your foot from the accelerator pedal. DISTRONIC PLUS
--- km/h An activation condition for DISTRONIC PLUS is not fulfilled.
X
Check the activation conditions for DISTRONIC PLUS
(Y page 195). DISTRONIC PLUS and
SPEEDTRONIC DISTRONIC PLUS and SPEEDTRONIC are faulty. A warning tone
also sounds.
X Visit a qualified specialist workshop. Cruise control and
SPEEDTRONIC inop‐
erative SPEEDTRONIC and cruise control are malfunctioning.
Aw arning tone also sounds.
X Visi taqualified specialist workshop. Display messages
287On-board computer and displays Z

Tyres
Display messages Possible causes/consequences and
M Solutions
Tyre pressure
Check tyres The tyre pressure loss warning system has detected a significant
loss in pressure.
Aw
arning tone also sounds.
G WARNING
With tyre pressures which are too low, there is a ris kofthe fol-
lowing hazards:
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 183).
X If there is a flat tyre, inspect the tyres (Y page 363).
X Check the tyre pressures and, if necessary, correct the tyre
pressure.
X Restart the tyre pressure loss warning system when the tyre
pressure is correct (Y page 385).Check tyre pres‐
sures
then restart Run
Flat Indicator The tyre pressure loss warning system generated a displaym
es-
sage 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 385).Run Flat Indicator
inoperative The tyre pressure loss warning system is faulty.
X
Visit a qualified specialist workshop. Tyre pressure
displayed after
driving for a few
minutes The tyre pressure monitor is measuring the tyre pressure.
X
Drive on.
The tyre pressures appear in the multifunction display after you
have been driving for a few minutes. Tyre press. monitor
inoperative The tyre pressure monitor is faulty.
X
Visit a qualified specialist workshop. Display messages
289On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
Tyre press. moni‐
tor inoperative No
wheel sensors The wheels fitted do no
thave a suitable tyre pressure sensor .The
tyre pressure monitor is deactivated.
X Fit wheels with suitable tyre pressure sensors.
The tyre pressure monitor is activated automatically after driv-
ing for a few minutes. Check
tyres The tyre pressure in one or more tyres has dropped significantly.
The wheel position is displayed in the multifunction display.
Aw
arning tone also sounds.
G WARNING
With tyre pressures which are too low, there is a ris kofthe fol-
lowing hazards:
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 183).
X If there is a flat tyre, inspect the tyres (Y page 363).
X Check the tyre pressure (Y page 386).
X If necessary, correct the tyre pressure. 290
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
Warning
tyre defect The tyre pressure in on
eormore tyres has dropped suddenly. The
wheel position is displayed in the multifunction display.
G WARNING
If you drive with a flat tyre, there is a risk of the following hazards:
R A flat tyre affects the ability to steer or brake the vehicle.
R You could lose control of the vehicle.
R Continued driving with a flat tyre will cause excessive heat build-
up and possibly a fire.
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 183).
X If there is a flat tyre, inspect the tyres (Y page 363).Rectify
tyre pressure 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 386).
X If necessary, correct the tyre pressure.
X Restart the tyre pressure monitor (Y page 387).Wheel sensor(s)
missing There is no signal from the tyre pressure sensor of one or several
wheels. The pressure of the affected tyre is not displayed in the
multifunction display.
X
Have the faulty tyre pressure sensor replaced at a qualified spe-
cialist workshop. Tyre press. monitor
currently unavail‐
able Due to a source of radio interference, no signals can be received
from the wheel sensors. The tyre pressure monitor is temporarily
malfunctioning.
X Drive on.
The tyre pressure monitor restarts automatically as soon as the
cause has been rectified. Display messages
291On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
h
Tyre pressure Cau‐
tion Tyre malfunc‐
tion The tyre pressure in one or more tyres has dropped suddenly.
Aw
arning tone also sounds.
G WARNING
If you drive with a flat tyre, there is a ris kofthe following hazards:
R A flat tyre affects the ability to steer or brake the vehicle.
R You could lose control of the vehicle.
R Continued driving with a flat tyre will cause excessive heat build-
up and possibly a fire.
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 183).
X If there is a flat tyre, inspect the tyres (Y page 363).h
Tyre pressure
Check tyre(s) The tyre pressure in one or more tyres has dropped significantly.
G WARNING
With tyre pressures which are too low, there is a risk of the fol-
lowing hazards:
R the tyres may burst, especially as the load and vehicle speed
increase.
R they 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 183).
X If there is a flat tyre, inspect the tyres (Y page 363).
X Check the tyre pressure (Y page 386).
X If necessary, correct the tyre pressure. h
Please correct
tyre pressure 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 386).
X If necessary, correct the tyre pressure. 292
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
Risk of vehicle
rolling
Transmission not
in P Vehicles with DIRECT SELECT lever:
The driver's doo
ris open and the transmission is in position R,N
or D.
Aw arning tone also sounds.
X Shift the transmission to position P.
X Secure the vehicle against rolling away ( Ypage 183). Without changing
gear,
consult workshop Vehicles with DIRECT SELECT lever:
You canno
tchange the transmission position due to a malfunction.
Aw arning tone also sounds.
If transmission position Dis selected:
X Drive to a qualified specialist workshop without shifting the
transmission from position D.
If transmission position R,Nor Pis selected:
X Consult a qualified specialist workshop. Only select
position P when
vehicle is station‐
ary Vehicles with DIRECT SELECT lever:
The vehicle is moving.
X
Pull ove rand stop the vehicle safely as soo nas possible, paying
attention to road and traffic conditions.
X Shift the transmission to position P.N Saloon: the boot lid is open.
X
Close the boot lid. A Estate: the tailgate is open.
G WARNING
When the engine is running, exhaust gases can enter the vehicle
interior if the tailgate is open.
There is a risk of poisoning.
X Close the tailgate. 294
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
M
or? The bonne
tis open. Awarning tone also sounds.
G WARNING
The open bonne tmay then bloc kyour view when the vehicle is in
motion.
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 183).
X Close the bonnet.
If the active bonnet (pedestrian protection) has been triggered:
X Reset the bonnet (Y page 344).
X Close the bonnet. Active bonnet mal‐
function See Own‐
er's Manual The active bonnet (pedestrian protection) is not active due to a
malfunction.
X
Visit a qualified specialist workshop. C At least one door is open.
Awarning tone also sounds.
X Close all doors. _
Rear left seat
backrest not
locked or
Rear right seat back‐
rest not locked Saloon with through-loading feature in the rear bench seat:
The backres
tinthe rear is not engaged on the left-hand and/or
right-hand side. Awarning tone also sounds.
X Push the backres tback until it engages. j
Check trailer
hitch lock The trailer tow hitch is no
tcorrectly engaged.
Aw arning tone also sounds.
X Stop the vehicle immediately, paying attentio ntoroad and traf-
fic conditions, and switch off the engine.
X Apply the parking brake.
X Allow the trailer tow hitch ball coupling to engage in the end
position (Y page 237). &
inoperative Bat‐
tery low The on-board voltage is too low. The auxiliary heating has switched
itself off or cannot be switched on (Y page 151).
X Drive for a longer distance.
The battery is being charged. The auxiliary heating is operational
again as soon as the on-board electrical system voltage is suf-
ficient. Display messages
295On-board computer and displays Z