
Display messages Possible causes/consequences and
M Solutions# The battery is not being charged.
A warning tone also sounds.
Possible causes are:
R
a defective alternator
R a torn poly-V-belt
R a malfunction in the electronics
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 167).
X Open the hood.
X Check whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do
not continue driving. The engine could otherwise overheat.
X Consult a qualified specialist workshop.
If the poly-V-belt is not damaged:
X Visit a qualified specialist workshop. 4
Check Engine Oil
At Next Refueling The engine oil level has dropped to the minimum level.
A warning tone also sounds.
X
Check the oil level when next refueling, at the latest
(Y page 295).
X If necessary, add engine oil ( Y page 296).
X Have the engine checked at a qualified specialist workshop if
engine oil needs to be added more often than usual.
! Avoid long journeys with too little engine oil. The engine will
otherwise be damaged.
Information on approved engine oils can be obtained from any
qualified specialist workshop or on the Internet at http://
www.mbusa.com (USA only). 8
Fuel Level Low The fuel level has dropped into the reserve range.
X
Refuel at the nearest gas station. Display messages
241
On-board computer and displays Z

Display messages Possible causes/consequences and
M SolutionsLane Keeping
Assist Currently
Unavailable See
Operator's Manual
or Active Lane
Keeping Assist
Currently
Unavailable See
Operator's Manual Lane Keeping Assist or Active Lane Keeping Assist is deactivated
and temporarily inoperative. Possible causes are:
R
the windshield in the camera's field of vision is dirty.
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.
When the causes stated above no longer apply, the display
message disappears.
Lane Keeping Assist or Active Lane Keeping 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 167).
X Clean the windshield. Lane Keeping
Assist
Inoperative or
Active Lane
Keeping Assist
Inoperative Lane Keeping Assist or Active Lane Keeping Assist is defective.
X
Visit a qualified specialist workshop. Display messages
243
On-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 167).
X Clean the sensors ( Y page 304).
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 194).
X Restart the engine.
If the display message continues to be displayed:
X Visit a qualified specialist workshop.244
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 167).
X Clean the sensors in the radiator grill and the bumper
(Y page 304).
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 177).246
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 167).
X If there is a flat tire, inspect the tires ( Y page 308).
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 329). 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 329).Run Flat Indicator
Inoperative The tire pressure loss warning system is faulty.
X
Visit a qualified specialist workshop. Tire pressures
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.248
Display messages
On-board computer and displays

Display messages Possible causes/consequences and
M SolutionsTire Pressure
Monitor
Inoperative No
Wheel Sensors The wheels mounted do not have a suitable tire pressure sensor.
The tire pressure monitor is deactivated.
X
Mount wheels with suitable tire pressure sensors.
The
tire pressure monitor is activated automatically after driving
for a few minutes. Check
Tire Press. The tire pressure in one or more tires has dropped significantly.
The wheel position is displayed in the multifunction display.
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 167).
X If there is a flat tire, inspect the tires ( Y page 308).
X Check the tire pressure (Y page 330).
X If necessary, correct the tire pressure. Warning
Tire Malfunction The tire pressure in one or more tires has dropped suddenly. The
wheel position is shown in the multifunction display.
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 167).
X If there is a flat tire, inspect the tires ( Y page 308). Display messages
249
On-board computer and displays Z

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 330).
X If necessary, correct the tire pressure.
X Restart the tire pressure monitor (Y page 332). 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 167).
X If there is a flat tire, inspect the tires ( Y page 308).250
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 167).
X If there is a flat tire, inspect the tires ( Y page 308).
X Check the tire pressure (Y page 330).
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 330).
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.P
Shift to 'P' You have attempted to stop the engine with the Start/Stop button
while the transmission was not in position P.
X
Shift the transmission to position P. Display messages
251
On-board computer and displays Z