Engine
Display messages Possible causes/consequences and
M Solutions+
Check Coolant
Level See
Operator's Manual The coolant level is too low.
!
Avoid
making long journeys with too little coolant in the engine
cooling system. The engine will otherwise be damaged.
X Add coolant, observing the warning notes before doing so
(Y page 331).
X If coolant needs to be added more often than usual, have the
engine coolant system checked at a qualified specialist
workshop. ? The fan motor is faulty.
X
At coolant temperatures under 248 ‡(120 †),
drive to the next
qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic. ?
Coolant Too Hot
Stop Vehicle Turn
Engine Off The coolant is too hot.
A warning tone also sounds.
G WARNING
Do not drive when your engine is overheated. This can cause some
fluids which may have leaked into the engine compartment to
catch fire.
Steam from the overheated engine can also cause serious burns
which can occur just by opening the hood.
There is a risk of injury.
X Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
X Secure the vehicle against rolling away ( Y page 175).
X Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.
X Do not start the engine again until the display message goes out
and the coolant temperature is under 248 ‡ (120
†).
Otherwise, the engine could be damaged.
X Pay attention to the coolant temperature display.
X If 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
248 ‡ (120 †).258
Display messages
On-board computer and displays
Display messages Possible causes/consequences and
M SolutionsØ
Check
Additive See
Operator's Manual The DEF tank is empty.
X
Have the DEF tank filled as soon as possible at a qualified
specialist workshop
(Y page 173).Ø
Remaining Starts:
16 The DEF level has fallen to a minimum.
X
Have the DEF tank filled immediately at a qualified specialist
workshop ( Y page 173). Driving systems
Display messages Possible causes/consequences and
M SolutionsÀ
Attention Assist:
Take a Break! Based on certain criteria, ATTENTION ASSIST has detected fatigue
or
a lack of concentration on the part of the driver. A warning tone
also sounds.
X If necessary, take a break.
During long journeys, take regular breaks in good time so you get
enough rest. À
Attention Assist
Inoperative ATTENTION ASSIST is inoperative.
X
Visit a qualified specialist workshop. ¨or°
Vehicle Rising Your vehicle is adjusting to the level you have selected.
¨or°
Vehicle Rising
Wait Briefly The vehicle level is too low when the vehicle is stationary. A
warning tone also sounds.
X
Do not pull away.
The vehicle level is set when the display message disappears. ¨or°
STOP Car Too Low You have pulled away while the vehicle level is still too low.
AIRMATIC sets the vehicle to the selected level after a short
period.
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 175).
X Wait until the display message disappears before pulling away. Display messages
261On-board computer and displays Z
Display messages Possible causes/consequences and
M SolutionsBlind Spot Assist
Currently
Unavailable See
Operator's Manual
or Active Blind
Spot Assist
Currently
Unavailable See
Operator's Manual Blind Spot Assist or Active Blind Spot Assist is temporarily
inoperative. Possible causes are:
R
the sensors are dirty.
R 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
stations or other sources of electromagnetic radiation.
The yellow 9 indicator lamps also light up in the exterior
mirrors.
When the causes stated above no longer apply, the display
message disappears.
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 175).
X Clean the sensors ( Y page 337).
X Restart the engine. Blind Spot Assist
Inoperative or
Active Blind Spot
Assist Inoperative Blind Spot Assist or Active Blind Spot Assist is defective.
The yellow
9 indicator lamps also light up in the exterior
mirrors.
X Visit a qualified specialist workshop. Parking Guidance
Inoperative Parking Guidance is malfunctioning (
Y page 205).
X Restart the engine.
If the display message continues to be displayed:
X Visit a qualified specialist workshop.264
Display messagesOn-board computer and displays
Display messages Possible causes/consequences and
M SolutionsDISTRONIC PLUS
Currently
Unavailable See
Operator's Manual DISTRONIC PLUS is temporarily inoperative. Possible causes are:
R
function is impaired due to heavy rain or snow.
R the sensors in the radiator grill and the bumper are dirty.
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 system is outside the operating temperature range.
R The on-board voltage is too low.
A warning tone also sounds.
When the causes stated above no longer apply, the display
message disappears.
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 175).
X Clean the sensors in the radiator grill and the bumper
(Y page 337).
X Restart the engine. DISTRONIC PLUS
Inoperative DISTRONIC PLUS is defective.
BAS PLUS (Brake Assist PLUS) and PRE-SAFE
®
Brake may be
inoperative as well.
A warning tone also sounds.
X Visit a qualified specialist workshop. DISTRONIC PLUS
Passive 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
- - - mph An activation condition for DISTRONIC PLUS is not fulfilled.
X
Check the activation conditions for DISTRONIC PLUS
(Y page 185).266
Display messagesOn-board computer and displays
Tires
Display messages Possible causes/consequences and
M SolutionsCheck
Tire Pressure The tire pressure loss warning system has detected a significant
loss in pressure.
A warning tone also sounds.
G WARNING
With tire pressures which are too low, there is a risk of the
following hazards:
R they may burst, especially as the load and vehicle speed
increase.
R they
may wear excessively and/or unevenly, which may greatly
impair tire 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
maneuvers.
Pay attention to the traffic conditions as you do so.
X Secure the vehicle against rolling away ( Y page 175).
X If there is a flat tire, inspect the tires ( Y page 344).
X Check the tire pressures and, if necessary, correct the tire
pressure.
X Restart the tire pressure loss warning system when the tire
pressure is correct (Y page 370). Check Tire Pressure
Then Restart Run
Flat Indicator The tire pressure loss warning system generated a display
message and has not been restarted since.
X
Set the correct tire pressure in all four tires.
X Restart the tire pressure loss warning system ( Y page 370).Run Flat Indicator
Inoperative The tire pressure loss warning system is faulty.
X
Visit a qualified specialist workshop. Tire pressure
will be displayed
after driving a
few minutes The tire pressure monitor is measuring the tire pressure.
X
Drive on.
The
tire pressures appear in the multifunction display after you
have been driving for a few minutes. Tire Press. Monitor
Inoperative The tire pressure monitor is faulty.
X
Visit a qualified specialist workshop.268
Display messages
On-board computer and displays
Display messages Possible causes/consequences and
M SolutionsCorrect
Tire Pressure The tire pressure is too low in at least one of the tires, or the tire
pressure difference between the wheels is too great.
X
Check the tire pressures at the next opportunity (Y page 370).
X If necessary, correct the tire pressure.
X Restart the tire pressure monitor (Y page 373). TirePress.
Sensor(s) Missing There is no signal from the tire pressure sensor of one or several
wheels. The pressure of the affected tire is not displayed in the
multifunction display.
X
Have the faulty tire pressure sensor replaced at a qualified
specialist workshop. Tire Press. Monitor
Currently
Unavailable Due to a source of radio interference, no signals can be received
from the wheel sensors. The tire pressure monitor is temporarily
malfunctioning.
X
Drive on.
The
tire pressure monitor restarts automatically as soon as the
problem has been solved. h
Tire Press.
Warning Tire
Malfunction The tire pressure in one or more tires has dropped suddenly.
A warning tone also sounds.
G WARNING
If you drive with a flat tire, there is a risk of the following hazards:
R A flat tire affects the ability to steer or brake the vehicle.
R You could lose control of the vehicle.
R Continued
driving with a flat tire 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
maneuvers.
Pay attention to the traffic conditions as you do so.
X Secure the vehicle against rolling away ( Y page 175).
X If there is a flat tire, inspect the tires ( Y page 344).270
Display messages
On-board computer and displays
Display messages Possible causes/consequences and
M Solutionsh
Tire Press. Check
Tire Pressure The tire pressure in one or more tires has dropped significantly.
G WARNING
With tire pressures which are too low, there is a risk of the
following hazards:
R they may burst, especially as the load and vehicle speed
increase.
R they
may wear excessively and/or unevenly, which may greatly
impair tire 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
maneuvers.
Pay attention to the traffic conditions as you do so.
X Secure the vehicle against rolling away ( Y page 175).
X If there is a flat tire, inspect the tires ( Y page 344).
X Check the tire pressure (Y page 370).
X If necessary, correct the tire pressure. h
Correct Tire
Pressure The tire pressure is too low in at least one of the tires, or the tire
pressure difference between the wheels is too great.
X
Check the tire pressures at the next opportunity (Y page 370).
X If necessary, correct the tire pressure. Vehicle
Display messages Possible causes/consequences and
M SolutionsShift to 'P' or 'N'
to Start Engine You have attempted to start the engine with the transmission in
position R or D.
X
Shift the transmission to position P or N.Auxiliary Battery
Malfunction The auxiliary battery for the automatic transmission is no longer
being charged.
X
Visit a qualified specialist workshop. Apply Brake to
Shift
from 'P' You have attempted to move the transmission selector lever to
position D, R or N without depressing the brake pedal.
X
Depress the brake pedal. Display messages
271
On-board computer and displays Z
SmartKey
Display messages Possible causes/consequences and
M SolutionsÂ
Key Does Not
Belong to Vehicle You have put the wrong SmartKey in the ignition lock.
X
Use the correct SmartKey. Â
Take
Your Key from
Ignition The SmartKey is in the ignition lock.
X
Remove the SmartKey. Â
Obtain a New Key The SmartKey needs to be replaced.
X
Visit a qualified specialist workshop. Â
Replace
Key Battery The batteries of the KEYLESS-GO key are discharged.
X
Change the batteries ( Y page 81).Â
Don't Forget Your
Key The display message is shown for a maximum of 60 seconds and
is only a reminder.
You have opened the driver's door with the engine switched off.
The KEYLESS-GO key is not in the ignition lock.
X
Remember to take the KEYLESS-GO key with you when you
leave the vehicle. Â
Key Not Detected
(red display message) The KEYLESS-GO key is not in the vehicle.
A warning tone also sounds.
If the engine is switched off, you can no longer lock the vehicle
centrally 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 175).
X Locate the KEYLESS-GO key. The KEYLESS-GO key is not detected while the engine is running
because
there is interference from a strong source of radio waves.
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 175).
X Operate the vehicle with the SmartKey in the ignition lock.274
Display messages
On-board computer and displays