Display messages Possible causes/consequences and
0050 Solutions0027(USA
only)004D(Canada
only)
Check Brake Fluid
Level There is not enough brake fluid in the brake fluid reservoir.
In addition, the 0027 (USA only)/004D (Canada only) warning
lamp lights up in the instrument cluster and a warning tone
sounds.
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 160).
X Consult a qualified specialist workshop.
X Do not add brake fluid. This does not correct the malfunction. 0026
Check Brake Pad
Wear The brake pads/linings have reached their wear limit.
X
Visit a qualified specialist workshop. 0053
mbrace Inoperative One or more main features of the mbrace system are
malfunctioning.
X
Have the mbrace system checked immediately at a qualified
specialist workshop. PRE-SAFE
Inoperative See
Operator's Manual
Important functions of PRE-SAFE
®
have failed. All other
occupant
safety systems, e.g. air bags, remain available.
X Visit a qualified specialist workshop immediately.234
Display messages
On-board computer and displays
Display messages Possible causes/consequences and
0050 SolutionsPRE-SAFE
Functions
Currently Limited
See Operator's
Manual
PRE-SAFE
®
Brake 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.
When the causes stated above no longer apply, the display
message disappears.
PRE-SAFE ®
Brake 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 160).
X Clean the sensors in the radiator grill and the bumper
(Y page 307).
X Restart the engine. PRE-SAFE
Functions Limited
See Operator's
Manual
PRE-SAFE
®
Brake is inoperative due to a malfunction. BAS PLUS
or the distance warning signal may also have failed.
X Visit a qualified specialist workshop. 0075
SRS Malfunction
Service Required There is a malfunction in the SRS (Supplemental Restraint
System). The 0075 warning lamp also lights up in the instrument
cluster.
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 Visit a qualified specialist workshop.
For further information about SRS, see (Y page 41). Display messages
235
On-board computer and displays Z
Display messages Possible causes/consequences and
0050 Solutions0049
Check Trailer Left
Turn Signal or
Check Trailer
Right Turn Signal The left or right-hand trailer turn signal lamp is defective.
X
Check whether you are permitted to change the bulb yourself.
or
X Visit a qualified specialist workshop. 0049
Check Trailer
Brake Lamp The trailer brake lamp is defective.
X
Check whether you are permitted to change the bulb yourself.
or
X Visit a qualified specialist workshop. 0049
Check Rear Left
Turn Signal or
Check Rear Right
Turn Signal The rear left-hand or rear right-hand turn signal is defective.
X
Check whether you are permitted to replace the bulb yourself
(Y page 116).
or
X Visit a qualified specialist workshop. 0049
Check Front Left
Turn Signal or
Check Front Right
Turn Signal The front left-hand or front right-hand turn signal is defective.
X
Check whether you are permitted to replace the bulb yourself
(Y page 116).
or
X Visit a qualified specialist workshop. 0049
Check Left Mirror
Turn Signal or
Check
Right Mirror
Turn Signal The turn signal in the left-hand or right-hand exterior mirror is
defective.
X
Check whether you are permitted to replace the bulb yourself
(Y page 116).
or
X Visit a qualified specialist workshop. 0049
Check Center Brake
Lamp The high-mounted brake lamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 116).
or
X Visit a qualified specialist workshop. 0049
Check Left Tail
and Brake Lamps
or
Check Right Tail
and Brake Lamps The left or right-hand tail lamp/brake lamp is defective.
X
Check whether you are permitted to replace the bulb yourself
(Y page 116).
or
X Visit a qualified specialist workshop.240
Display messagesOn-board computer and displays
Display messages Possible causes/consequences and
0050 Solutions0099
Eng. Start Not
Possible in ..km The DEF system is malfunctioning. A warning tone also sounds.
X
Visit a qualified specialist workshop immediately. 0099
Eng. Start Not
Possible The DEF system is malfunctioning. A warning tone also sounds.
You can no longer start the engine.
X
Consult a qualified specialist workshop immediately. Driving systems
Display messages Possible causes/consequences and
0050 Solutions00AD
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. 00AD
Attention Assist
Inoperative ATTENTION ASSIST is inoperative.
X
Visit a qualified specialist workshop. 00D9
Off The HOLD function is deactivated. The vehicle is skidding.
A warning tone also sounds.
X
Reactivate the HOLD function later (Y page 179). The HOLD function is deactivated. When the brake pedal is firmly
depressed, an activation condition is not fulfilled.
A warning tone also sounds.
X
Check the activation conditions for the HOLD function
(Y page 179). Radar Sensor
Deactivated See
Operator's Manual The radar sensor system is deactivated.
X
Switch on the radar sensor system (Y page 229). Display messages
247On-board computer and displays Z
Display messages Possible causes/consequences and
0050 SolutionsDISTRONIC PLUS
Inoperative
DISTRONIC PLUS is defective. BAS PLUS and PRE-SAFE
®
Brake
may also have failed.
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 171). Cruise Control
Inoperative Cruise control is defective.
A warning tone also sounds.
X
Visit a qualified specialist workshop. Cruise Control
--- mph A condition for activating cruise control has not been fulfilled.
You have tried to store a speed below 20 mph (30 km/h), for
example.
X
If conditions permit, drive faster than 20 mph (30 km/h ) and
store the speed.
X Check the activation conditions for cruise control
(
Y page 169). Display messages
251
On-board computer and displays Z
Display messages Possible causes/consequences and
0050 SolutionsCheck
Tires 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 160).
X Check the tires and, if necessary, follow the instructions for a
flat tire (Y page 312).
X Check the tire pressure (Y page 336).
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 160).
X Check the tires and, if necessary, follow the instructions for a
flat tire (Y page 312). Display messages
253
On-board computer and displays Z
Safety systems
Problem Possible causes/consequences and
0050 Solutions0027 (USA only)
004D (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 160).
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. 0025
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, hill
start assist and ESP ®
trailer stabilization 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 in the instrument cluster
259
On-board computer and displays Z
Problem Possible causes/consequences and
0050 Solutions0025
The yellow ABS warning
lamp is lit while the
engine is running. ABS is temporarily unavailable. BAS, BAS PLUS, ESP
®
, EBD
(electronic brake force distribution), PRE-SAFE ®
,
PRE-SAFE ®
Brake, the HOLD function, hill start assist and
ESP ®
trailer stabilization are therefore also deactivated, for
example.
Possible causes are:
R Self-diagnosis is not yet complete.
R The on-board voltage may be insufficient.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear 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 a risk of an accident.
X Carefully drive a suitable distance, making slight steering
movements at a speed above 12 mph (20 km/h).
The functions mentioned above are available again when the
warning lamp goes out.
If the warning lamp is still on:
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop.260
Warning and indicator lamps in the instrument cluster
On-board computer and displays