
Display messagesPossible causes/consequences and M Solutions?
Coolant Stop car,
turn engine offThe coolant is too hot.
A warning tone also sounds.GWARNING
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.
Steam from an overheated engine can cause serious burns, which
can occur just by opening the bonnet.
There is a risk of injury.
XStop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.XSecure the vehicle against rolling away ( Y page 162).XWait until the engine has cooled down.XMake sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.XDo not start the engine again until the display message goes out
and the coolant temperature is below 120 †. The engine may
otherwise be damaged.XPay attention to the coolant temperature display.XIf the temperature increases again, visit a qualified specialist
workshop immediately.
Under normal operating conditions and with the specified coolant
level, the coolant temperature may rise to 120 †.
#The battery is not being charged.
A warning tone also sounds.
Possible causes:
R faulty alternator
R torn poly-V-belt
R a malfunction in the electronicsXStop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.XOpen the bonnet.XCheck whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not continue driving. The engine could otherwise overheat.
XConsult a qualified specialist workshop.
If the poly-V-belt is OK:
XVisit a qualified specialist workshop immediately.Display messages241On-board computer and displaysZProCarManuals.com

Display messagesPossible causes/consequences and M SolutionsSpeed Limit Assist
currently unavail‐
able See Owner's
ManualSpeed Limit 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.XClean the windscreen.
If the system detects that the camera is fully operational, the dis-
play message disappears.
Speed Limit Assist is operational again.
Speed Limit Assist:
Unavailable in
this countrySpeed Limit Assist is only available in certain countries.XDrive on.
Speed Limit Assist is available again as soon as you drive into a
country in which its use is approved.Speed Limit Assist
inoperativeSpeed Limit Assist is faulty.XVisit a qualified specialist workshop.ë
OffThe HOLD function is deactivated. The vehicle is skidding.
A warning tone also sounds.XReactivate the HOLD function later ( Y page 181).The HOLD function is deactivated. When the brake pedal is firmly
depressed, an activation condition is not fulfilled.
A warning tone also sounds.XCheck the activation conditions for the HOLD function
( Y page 181).Radar sensor deac‐
tivated See Own‐
er's ManualThe radar sensor system is deactivated.XSwitch on the radar sensor system ( Y page 223).Display messages243On-board computer and displaysZProCarManuals.com

Display messagesPossible causes/consequences and M SolutionsLane Keeping
Assist currently
unavailable See
Owner's ManualLane 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 are no lane markings for a longer 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:XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XSecure the vehicle against rolling away ( Y page 162).XClean the windscreen.Lane Keeping
Assist inoperativeLane Keeping Assist is faulty.XVisit a qualified specialist workshop.Blind Spot Assist
currently unavail‐
able See Owner's
ManualBlind Spot Assist is temporarily inoperative.
You have established the electrical connection between the trailer
and your vehicle.XPress a on the steering wheel to confirm the display mes-
sage.
Blind Spot Assist is deactivated while towing a trailer.
244Display messagesOn-board computer and displays
ProCarManuals.com

Display messagesPossible causes/consequences and M SolutionsBlind Spot Assist is temporarily inoperative. 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 9 indicator 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 is operational again.
If the display message does not disappear:XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XSecure the vehicle against rolling away ( Y page 162).XClean the sensors ( Y page 291).XRestart the engine.Blind Spot Assist
inoperativeBlind Spot Assist is faulty.
The yellow 9 indicator lamps also light up in the exterior mir-
rors.XVisit a qualified specialist workshop.Park Assist cancel‐
ledThe driver's door is open and the driver's seat belt has not been
fastened.XRepeat 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.XWhile steering intervention is active, make sure not to touch the
multifunction steering wheel.The vehicle has started to skid and ESP ®
has intervened.XUse Active Parking Assist again later ( Y page 186).Display messages245On-board computer and displaysZProCarManuals.com

Display messagesPossible causes/consequences and M SolutionsPark Assist inoper‐
ativeYou have just carried out a large number of turning or parking
manoeuvres.
Active Parking Assist will become available again after approx-
imately ten minutes ( Y page 186).XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XSwitch off and restart the engine.
If the display message continues to be displayed:
XVisit a qualified specialist workshop.PARKTRONIC is faulty.XVisit a qualified specialist workshop.DISTRONIC PLUS offDISTRONIC PLUS has been deactivated ( Y page 173). If it was
deactivated automatically, a warning tone also sounds.DISTRONIC PLUS
available againDISTRONIC PLUS is operational again after having been tempo-
rarily unavailable. You can now reactivate DISTRONIC PLUS
( Y page 173).DISTRONIC PLUS cur‐
rently unavailable
See Owner's ManualDISTRONIC PLUS is temporarily inoperative. Possible causes:
R the function is impaired due to heavy rain or snow.
R the sensors in the radiator trim 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.
A warning tone also sounds.
Once the causes listed above no longer apply, the display message
goes out.
DISTRONIC is operational again.
If the display message does not disappear:XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XSecure the vehicle against rolling away ( Y page 162).XClean the sensors in the radiator trim ( Y page 291).XRestart the engine.246Display messagesOn-board computer and displays
ProCarManuals.com

TyresDisplay messagesPossible causes/consequences and M SolutionsTyre pressure
Check tyresThe tyre pressure loss warning system has detected a significant
loss in pressure.
A warning tone also sounds.GWARNING
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 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.
XStop the vehicle without making any sudden steering or braking
manoeuvres. Pay attention to the traffic conditions as you do
so.XSecure the vehicle against rolling away ( Y page 162).XCheck the tyres and, if necessary, follow the instructions for a
flat tyre ( Y page 298).XCheck the tyre pressures and, if necessary, correct the tyre
pressure.XRestart the tyre pressure loss warning system when the tyre
pressure is correct ( Y page 321).Check tyre pres‐
sures
then restart Run
Flat IndicatorThe tyre pressure loss warning system generated a display mes-
sage and has not been restarted since.XSet the correct tyre pressure in all four tyres.XRestart the tyre pressure loss warning system ( Y page 321).Run Flat Indicator
inoperativeThe tyre pressure loss warning system is faulty.XVisit a qualified specialist workshop.Please correct the
tyre pressureThe tyre pressure is too low in at least one of the tyres, or the tyre
pressure difference between the wheels is too great.XCheck the tyre pressures at the next opportunity
( Y page 322).XIf necessary, correct the tyre pressure.XRestart the tyre pressure monitor ( Y page 324).248Display messagesOn-board computer and displays
ProCarManuals.com

Display messagesPossible causes/consequences and M SolutionsCheck tyresThe tyre pressure in one or more tyres has dropped significantly.
The wheel position is displayed in the multifunction display.
A warning tone also sounds.GWARNING
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 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.
XStop the vehicle without making any sudden steering or braking
manoeuvres. Pay attention to the traffic conditions as you do
so.XSecure the vehicle against rolling away ( Y page 162).XCheck the tyres and, if necessary, follow the instructions for a
flat tyre ( Y page 298).XCheck the tyre pressure ( Y page 322).XIf necessary, correct the tyre pressure.Caution, tyre
defectThe tyre pressure in one or more tyres has dropped suddenly. The
wheel position is displayed in the multifunction display.GWARNING
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.
XStop the vehicle without making any sudden steering or braking
manoeuvres. Pay attention to the traffic conditions as you do
so.XSecure the vehicle against rolling away ( Y page 162).XCheck the tyres and, if necessary, follow the instructions for a
flat tyre ( Y page 298).Display messages249On-board computer and displaysZProCarManuals.com

Safety systemsProblemPossible causes/consequences and M SolutionsJ
The red brake system
warning lamp is lit while
the engine is running. A
warning tone also
sounds.There is insufficient brake fluid in the brake fluid reservoir.GWARNING
The braking efficiency may be impaired.
There is a risk of an accident.
XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.XSecure the vehicle against rolling away ( Y page 162).XDo not top up the brake fluid. Topping up will not rectify the
fault.XConsult a qualified specialist workshop.XObserve the additional display messages in the multifunction
display.!
The yellow ABS warning
lamp is lit while the
engine is running.ABS (Anti-lock Brake System) has been deactivated due to a fault.
Therefore, BAS (Brake Assist), COLLISION PREVENTION ASSIST,
COLLISION PREVENTION ASSIST PLUS, ESP ®
(Electronic Stability
Program), PRE-SAFE ®
, the HOLD function, hill start assist, the
adaptive brake lights and ESP ®
trailer stabilisation, for example,
are also deactivated.
ATTENTION ASSIST is deactivated.GWARNING
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.
XObserve the additional display messages in the multifunction
display.XDrive on carefully.XVisit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic trans-
mission, will be unavailable.
256Warning and indicator lamps in the instrument clusterOn-board computer and displays
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