Display messages Possible causes/consequences and
M SolutionsAct. Lane Keep.
Assist Currently
Unavailable See
Operator's Manual 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.
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 154).
X Clean the windshield.
If the system detects that the camera is fully operational, the
display message disappears.
Lane Keeping Assist or Active Lane Keeping Assist is operational
again. Act. Lane Keep.
Assist Inoperative Active Lane Keeping Assist is defective.
X
Visit a qualified specialist workshop. Active Blind Spot
Assist Currently
Unavailable See
Operator's Manual 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.
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 154).
X Clean the sensors ( Y page 504).
X Restart the engine.
If the system detects that the sensors are fully operational, the
display message disappears.
Active Blind Spot Assist is operational again. Display messages
243
On-board computer and displays Z
Display messages Possible causes/consequences and
M SolutionsDISTRONIC PLUS
Currently
Unavailable See
Operator's Manual DISTRONIC is deactivated and temporarily inoperative. Possible
causes are:
R
the DISTRONIC PLUS cover in the radiator trim is dirty
R function is impaired due to heavy rain or snow.
R the sensors 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
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.
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 154).
X Clean the DISTRONIC PLUS cover in the radiator trim and the
bumper ( Y page 504).
X Restart the engine.
If the system detects that the sensors are fully operational, the
display message disappears.
DISTRONIC is operational again. 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 164). Display messages
245On-board computer and displays Z
Tires
Display messages Possible causes/consequences and
M Solutions
Check
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 154).
X If there is a flat tire, inspect the tires ( Y page 509).
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 533). 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 533).
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. Display messages
247
On-board computer and displays Z
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 154).
X If there is a flat tire, inspect the tires ( Y page 509).
X Check the tire pressure (Y page 534).
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 154).
X If there is a flat tire, inspect the tires ( Y page 509).248
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 154).
X If there is a flat tire, inspect the tires ( Y page 509).
X Check the tire pressure (Y page 534).
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 534).
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 at the next opportunity.
X Until then, set the automatic transmission to position P before
you switch off the engine.
X Before leaving the vehicle, apply the electric parking brake.
X Secure the vehicle against rolling away ( Y page 154).250
Display messages
On-board computer and displays
Safety systems
Problem Possible causes/consequences and
M Solutions$ (USA only)
J (Canada only)
The red brake system
warning
lamp
comes on
while the engine is
running. A warning tone
also sounds. There is not enough brake fluid in the brake fluid reservoir.
G WARNING
The braking effect may be impaired.
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. Do not continue driving
under any circumstances.
X Secure the vehicle against rolling away ( Y page 154).
X Do not add brake fluid. Topping up will not remedy the
malfunction.
X Consult a qualified specialist workshop.
X Observe 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) is deactivated due to a malfunction.
BAS (Brake Assist), BAS PLUS, ESP
®
(Electronic Stability
Program), PRE-SAFE ®
, PRE-SAFE ®
Brake, the HOLD function and
hill start assist are therefore also deactivated, for example.
ATTENTION ASSIST is deactivated.
G WARNING
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
affected. The braking distance in an emergency braking situation
can increase.
If ESP ®
is
not operational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit 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
transmission, will not be available. Warning and indicator lamps
257
On-board computer and displays Z
Problem Possible causes/consequences and
M Solutions$ (USA only)
! (Canada only)
The red indicator lamp
for the electric parking
brake flashes and/or
the yellow
!
The warning lamp for
the electric parking
brake lights up. The electric parking brake is temporarily malfunctioning or
defective.
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 154).
X Observe the additional display messages in the multifunction
display. 6
The red SRS warning
lamp is lit while the
engine is running.
There is a malfunction in the SRS (Supplemental Restraint
System).
G WARNING
The air bags or Emergency Tensioning Devices may either be
triggered unintentionally or, in the event of an accident, may not
be triggered.
There is an increased risk of injury.
X Drive on carefully.
X Have SRS checked at a qualified specialist workshop
immediately.
Further information on occupant safety (Y page 37). 262
Warning and indicator lampsOn-board computer and displays
Problem Possible causes/consequences and
M Solutions?
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 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 154).
X Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and add coolant, observing the warning
notes (Y page 498).
X If you need to add coolant more often than usual, have the
engine coolant system checked.
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 coolant temperature is
under 248
‡ (120 †). Otherwise, the engine could be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic. ?
The red coolant
warning
lamp
comes on
while the engine is
running. A warning tone
also sounds. The coolant temperature has exceeded 248 ‡ (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.
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 Observe the additional display messages in the multifunction
display.
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 154).264
Warning and indicator lamps
On-board computer and displays