
Display messages
Possible causes/consequences and
M
MSolutions Active Parking Assist is unavailable or faulty.
X Switch off the ignition and restart the engine.
If Active Parking Assist continues to be unavailable (the jsymbol
does not appear in the multifunction display):
X Consult a qualified specialist workshop. Park Assist
Park Assist
switched off switched off The vehicle is parked. A warning tone also sounds.
The display message disappears automatically. DISTRONIC PLUS off
DISTRONIC PLUS off DISTRONIC PLUS has been deactivated.
If a warning tone also sounds, DISTRONIC PLUS has switched itself off.
(Y page 182) DISTRONIC PLUS DISTRONIC PLUS
available again available again DISTRONIC PLUS is operational again after having been temporarily
unavailable. You can now reactivate DISTRONIC PLUS (Y
page 182).DISTRONIC PLUS cur‐ DISTRONIC PLUS cur‐
rently unavailable rently unavailable
See Owner's Manual See Owner's Manual DISTRONIC PLUS is temporarily inoperative.
Steering Assist and Stop&Go Pilot are temporarily inoperative.
Possible causes:
R the function is impaired due to heavy rain or snow
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 system is outside the operating temperature range
R the on-board voltage is too low.
A warning tone also sounds.
Once the causes listed above no longer apply, the display message
goes out.
DISTRONIC PLUS 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 Safeguard the vehicle against rolling away (Y page 167).
X Restart the engine. DISTRONIC DISTRONIC
PLUS
PLUSinop‐
inop‐
erative
erative DISTRONIC PLUS is faulty.
The following may have also failed:
R BAS PLUS with Cross-Traffic Assist
R PRE-SAFE ®
Brake
R Steering Assist and Stop&Go Pilot
A warning tone also sounds.
X Consult a qualified specialist workshop. DISTRONIC PLUS sus‐ DISTRONIC PLUS sus‐
pended pended 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. 276
Display
messagesOn-board computer and displays 

Tyres
Display messages
Possible causes/consequences and
M
MSolutions Tyre
Tyre
pressure
pressure Check
Check
tyres
tyres The tyre pressure loss warning system has detected a significant loss
in pressure.
A warning tone also sounds.
Possible causes:
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 Safeguard the vehicle against rolling away (Y page 167).
X Check the tyres and, if necessary, follow the instructions for a flat
tyre (Y page 333).
X Check the tyre pressures and, if necessary, correct the tyre pres-
sure.
X Restart the tyre pressure loss warning system when the tyre pres-
sure is correct (Y page 353). 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 353).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 354).
X If necessary, correct the tyre pressure.
X Restart the tyre pressure monitor (Y page 355). Display
messages
279On-board computer and displays Z 

Display messages
Possible causes/consequences and
M
MSolutions Check tyre(s)
Check tyre(s) The tyre pressure in one or more tyres has dropped significantly. The
wheel position is displayed in the multifunction display.
A warning tone also sounds.
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 167).
X Check the tyres and, if necessary, follow the instructions for a flat
tyre (Y page 333).
X Check the tyre pressure (Y page 354).
X If necessary, correct the tyre pressure. Warning tyre defect Warning tyre defect The tyre pressure in one or more 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 167).
X Check the tyres and, if necessary, follow the instructions for a flat
tyre (Y page 333). Tyre Tyre
press.
press. monitor
monitor
currently unavaila‐
currently unavaila‐
ble ble No signals can be received from the tyre pressure sensors due to
strong RF interference. The tyre pressure monitor is temporarily mal-
functioning.
X Drive on.
The tyre pressure monitor restarts automatically as soon as the
cause has been rectified. 280
Display
messagesOn-board computer and displays 

Display messages
Possible causes/consequences and
M
MSolutions Wheel sensor(s)
Wheel sensor(s)
missing 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 mul-
tifunction display.
X Have the faulty tyre pressure sensor replaced at a qualified spe-
cialist workshop. Tyre Tyre
press.
press. monitor
monitor
inoperative No
inoperative No
wheel sensors wheel sensors The wheels fitted do not have suitable tyre pressure sensors. The tyre
pressure monitor is deactivated.
X Fit wheels with suitable tyre pressure sensors.
The tyre pressure monitor is activated automatically after driving for
a few minutes. Tyre Tyre
press.
press. monitor
monitor
inoperative
inoperative The tyre pressure monitor is faulty.
X Consult a qualified specialist workshop. Vehicle
Display messages
Possible causes/consequences and
M
MSolutions To start engine,
To start engine,
shift to either P shift to either P
or N or N You have attempted to start the engine with the transmission in posi-
tion Ror D.
X Shift the transmission to position Por N. Apply
Apply
brake
braketo
todese‐
dese‐
lect Park (P) posi‐
lect Park (P) posi‐
tion tion You have attempted to shift the transmission to position
D,Ror N
without depressing the brake pedal.
X Depress the brake pedal. To shift out of P
To shift out of P
or or
N,
N,depress
depress brake
brake
and start engine
and start engine With the engine switched off, you have attempted to shift the trans-
mission out of position Por Ninto another transmission position.
X Depress the brake pedal.
X Start the engine. Risk of vehicle
Risk of vehicle
rolling Transmis‐ rolling Transmis‐
sion not in P sion not in P The driver's door is open/not fully closed and the transmission is in
position R,Nor D.
A warning tone also sounds.
G WARNING
The vehicle may roll away.
There is a risk of an accident.
X Shift the transmission to position P.
X Secure the vehicle against rolling away (Y page 167).
X Close the driver's door fully. Only select Park Only select Park
(P) (P)
when
when vehicle
vehicle is
is
stationary
stationary The vehicle is moving.
X
Stop the vehicle safely as soon as possible, paying attention to road
and traffic conditions.
X Shift the transmission to position P. Display
messages
281On-board computer and displays Z 

Display messages
Possible causes/consequences and
M
MSolutions 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 81).Â
Key not detected Key not detected
(white display message) The key is currently undetected.
X Change the location of the key in the vehicle.
If the key still cannot be detected:
X Operate the vehicle with the key in the ignition lock if necessary. Â
Key not detected Key not detected
(red display message) The key is not in the vehicle.
A warning tone also sounds.
If the engine is switched off, you can no longer lock the vehicle cen-
trally or start the engine.
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 167).
X Locate the key. Display
messages
285On-board computer and displays Z 

Display messages
Possible causes/consequences and
M
MSolutions Because there is interference from a strong source of radio waves, the
key is not detected whilst the engine is running.
A warning tone also sounds.
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 167).
X Insert the key into the ignition lock and bring into key mode. Â
Remove Remove
starting
starting but‐
but‐
ton,
ton, then
theninsert
insert key
key R
The key detection function has a temporary malfunction or is faulty.
R The key is continually undetected.
A warning tone also sounds.
X Insert the key into the ignition lock and turn it to the desired posi-
tion.
X Consult a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
General notes
Some systems carry out a self-diagnosis when the ignition is switched on. Several warning and
indicator lamps can thereby temporarily light up or flash. This behaviour is non-critical. These
warning and indicator lamps only indicate a malfunction if they light up or flash after the engine is started or during a journey. 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 41).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 41).
The warning tone ceases. 286
Wa
rning and indi cator lamps in the instrument clusterOn-board computer and displays 

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions ?
N
The red coolant warning lamp lights up while the engine is running and the
coolant temperature gauge is at the start of the scale.
The temperature sensor for the coolant temperature gauge is faulty.
The coolant temperature is no longer being monitored. There is a risk of engine
damage if the coolant temperature is too high.
X Stop the vehicle immediately, paying attention to road and traffic conditions,
and switch off the engine. Do not continue driving under any circumstances.
X Safeguard the vehicle against rolling away (Y page 167).
X Consult a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
295On-board computer and displays Z 

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
M Solutions ?
N
The red coolant warning lamp comes on while the engine is running.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator may be blocked or the electric engine radiator fan may be malfunctioning.
The coolant is too hot and the engine is no longer being cooled sufficiently.
X Observe the additional display messages in the multifunction display.
X Stop the vehicle immediately, paying attention to road and traffic conditions,
and switch off the engine.
X Safeguard the vehicle against rolling away (Y page 167).
X Leave the vehicle and keep a safe distance from the vehicle until the engine has
cooled down.
X Check the coolant level and top up the coolant, observing the warning notes
(Y page 321).
X If you have to top up the coolant frequently, have the engine cooling system
checked.
X Make sure that the air supply to the engine radiator is not blocked, e.g. by frozen
slush.
X Do not start the engine again until the coolant temperature is below 120 †. The
engine may otherwise be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving in mountainous terrain
and stop-start traffic. ?
N
The red coolant warning lamp comes on while the engine is running.
The coolant temperature has exceeded 120 †. The airflow to the engine radiator may be blocked or the coolant level may be too low.
G WARNING
The engine is not being cooled sufficiently and may be damaged.
Never drive with an overheated engine. Driving when your engine is overheated
can cause some fluids which may have leaked into the engine compartment to
catch fire.
In addition, steam from an overheated engine can cause serious burns, which can
occur just by opening the bonnet.
There is a risk of injury.
X Observe the additional display messages in the multifunction display.
X Stop the vehicle immediately, paying attention to road and traffic conditions,
and switch off the engine.
X Safeguard the vehicle against rolling away (Y page 167).
X Leave the vehicle and keep a safe distance from the vehicle until the engine has
cooled down.
X Check the coolant level and top up the coolant, observing the warning notes
(Y page 321).
X If you have to top up the coolant frequently, have the engine cooling system
checked. 296
Warning and indicator lamps in the instrument clusterOn-board computer and displays