
Display messages Possible causes/consequences and 
M SolutionsF(USA
only)J(Canada
only)
Please Release 
Parking Brake You are driving with the parking brake applied. A warning tone also
sounds.
X
Release the parking brake. $(USA
only)J(Canada
only)
Brake Immediately A malfunction has occurred while the HOLD function or
DISTRONIC PLUS is active.
A 
tone may also sound at regular intervals. If you attempt to lock
the vehicle, the tone becomes louder.
You cannot start the engine.
X Paying attention to the traffic situation, immediately depress the
brake pedal firmly and hold until the display message
disappears.
X Secure the vehicle against rolling away ( Y page 167).
You can restart the engine. $(USA
only)J(Canada
only)
Check Brake Fluid 
Level There is not enough brake fluid in the brake fluid reservoir.
In addition, the $ (USA only)/J (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 167).
X Consult a qualified specialist workshop.
X Do not add brake fluid. This does not correct the malfunction. #
Check Brake Pad 
Wear The brake pads/linings have reached their wear limit.
X
Visit a qualified specialist workshop. G
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. Display messages
231
On-board computer and displays Z 

Display messages Possible causes/consequences and 
M SolutionsPRE-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. PRE-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 167).
X Clean the sensors in the radiator grill and the bumper
(Y page 304).
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. A
Malfunction 
Service Required G
Risk of injury
Cabriolet: the roll bars are defective.
X Visit a qualified specialist workshop immediately.232
Display messages
On-board computer and displays 

Display messages Possible causes/consequences and 
M Solutions6
SRS Malfunction 
Service Required There is a malfunction in the SRS (Supplemental Restraint
System). The 6 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 39). 6
Front Left 
Malfunction 
Service Required 
or Front Right 
Malfunction 
Service Required SRS has malfunctioned at the front on the left or right. The 
6
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. 6
Rear Left 
Malfunction 
Service Required 
or Rear Right 
Malfunction 
Service Required 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.
SRS has malfunctioned at the rear on the left or right. The  6
warning lamp also lights up in the instrument cluster.
X Visit a qualified specialist workshop. 6
Left Side Curtain 
Airbag 
Malfunction 
Service Required 
or Right Side 
Curtain Airbag 
Malfunction 
Service Required There is a malfunction in the left-hand or right-hand window
curtain air bag (Coupe) or head bag (Cabriolet).
The 6 warning lamp also lights up in the instrument cluster.
G WARNING
The left or right window curtain air bag (Coupe) or headbag
(Cabriolet) 
 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. Display messages
233
On-board computer and displays Z 

Display messages Possible causes/consequences and 
M SolutionsFront Passenger 
Airbag Enabled
See Operator's 
Manual The front-passenger air bag is enabled during the journey, even
though:
R
a child, a small adult or an object weighing less than the
system's weight threshold is located on the front-passenger
seat.
or
R the front-passenger seat is unoccupied.
The system may detect objects or forces applying additional
weight on the seat.
G WARNING
The air bag may deploy unintentionally.
There is an increased risk of injury.
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 Switch the ignition off.
X Open the front-passenger door.
X Remove the child and the child restraint system from the front-
passenger seat.
X Make sure that there are no objects on the seat adding to the
weight.
The system may otherwise detect the additional weight and
interpret the seat occupant's weight as greater than it actually
is.
X Keep the seat unoccupied, close the front-passenger door and
switch on the ignition.
X Observe the  ^a  indicator lamp in the center console and
the multifunction display and check the following:
Seat unoccupied and ignition switched on:
R the  45 
indicator lamp must light up and remain lit. When
the indicator lamp is on, OCS (Occupant Classification System)
has deactivated the front-passenger air bag ( Y page 46).
R the Front Passenger Airbag Enabled See Operator's 
Manual or Front Passenger Airbag Disabled See 
Operator's Manual display messages must not be shown in
the multifunction display.
X Wait for a period of at least 60 seconds until the necessary
system checks have been completed.
X Make sure that the display messages do not appear in the
multifunction display.234
Display messages
On-board computer and displays 

Display messages Possible causes/consequences and 
M SolutionsIf these conditions are fulfilled, the front-passenger seat can be
occupied 
again. Whether the  45 indicator lamp remains lit
or goes out depends on how OCS classifies the occupant.
If the conditions are not fulfilled, the system is not operating
correctly.
X Visit a qualified specialist workshop immediately.
For further information about the Occupant Classification System,
see ( Y page 46). Front Passenger 
Airbag Disabled
See Operator's 
Manual The front-passenger air bag is disabled during the journey, even
though:
R
an adult
or
R a person larger than a certain size is occupying the front-
passenger seat.
If additional forces are applied to the seat, the system may
interpret the occupant's weight as lower than it actually is.
G WARNING
The front-passenger air bag does not deploy during an accident.
There is an increased risk of injury.
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 Switch the ignition off.
X Have the occupant get out of the vehicle.
X Keep the seat unoccupied, close the front-passenger door and
switch on the ignition.
X Observe the  45 
 indicator lamp in the center console and
the multifunction display and check the following:
Seat unoccupied and ignition switched on:
R the  45 
indicator lamp must light up and remain lit. When
the indicator lamp is on, OCS has deactivated the front-
passenger air bag ( Y page 46).
R the Front Passenger Airbag Enabled See Operator's 
Manual or Front Passenger Airbag Disabled See 
Operator's Manual display messages must not be shown in
the multifunction display.
X Wait for a period of at least 60 seconds until the necessary
system checks have been completed.
X Make sure that the display messages do not appear in the
multifunction display. Display messages
235
On-board computer and displays Z 

Display messages Possible causes/consequences and 
M SolutionsIf these conditions are fulfilled, the front-passenger seat can be
occupied 
again. Whether the  45 indicator lamp remains lit
or goes out depends on how OCS classifies the occupant.
If the conditions are not fulfilled, the system is not operating
correctly.
X Visit a qualified specialist workshop immediately.
For further information about the Occupant Classification System,
see ( Y page 46). Lights
i Display messages about LEDs:
This display message will only appear if all LEDs have failed. Display messages Possible causes/consequences and 
M Solutionsb
Check Left 
Cornering Light
 or 
Check Right 
Cornering light The left or right-hand cornering light is defective.
X
Check whether you are permitted to change the bulb yourself
(Y page 130).
or
X Visit a qualified specialist workshop. b
Check Left Low 
Beam or Check 
Right Low Beam The left or right-hand low-beam headlamp is defective.
X
Check whether you are permitted to change the bulb yourself
(Y page 130).
or
X Visit a qualified specialist workshop. b
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 130).
or
X Visit a qualified specialist workshop. b
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 130).
or
X Visit a qualified specialist workshop.236
Display messages
On-board computer and displays 

Display messages Possible causes/consequences and 
M Solutionsb
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 130).
or
X Visit a qualified specialist workshop. b
Check 
Center Brake 
Lamp The high-mounted brake lamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 130).
or
X Visit a qualified specialist workshop. b
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 130).
or
X Visit a qualified specialist workshop. b
Check Left High 
Beam or Check 
Right High Beam The left or right-hand high beam is defective.
X
Check whether you are permitted to change the bulb yourself
(Y page 130).
or
X Visit a qualified specialist workshop. b
Check 
Left License 
Plate Lamp or 
Check Right 
License Plate Lamp The left or right-hand license plate lamp is defective.
X
Check whether you are permitted to change the bulb yourself
(Y page 130).
or
X Visit a qualified specialist workshop. b
Check Left Fog 
Lamp or Check 
Right Fog Lamp The left-hand or right-hand front fog lamp is defective.
X
Check whether you are permitted to change the bulb yourself
(Y page 130).
or
X Visit a qualified specialist workshop. Display messages
237
On-board computer and displays Z 

Display messages Possible causes/consequences and 
M Solutionsb
Rear Fog Lamp The rear fog lamp is defective.
X
Check whether you are permitted to change the bulb yourself
(Y page 130).
or
X Visit a qualified specialist workshop. b
Check Front Left 
Parking Lamp or 
Check Front Right 
Parking Lamp The front left or front right parking or standing lamp is defective.
X
Check whether you are permitted to change the bulb yourself
(Y page 130).
or
X Visit a qualified specialist workshop. b
Check 
Left Reverse 
Lamp or Check 
Right Reverse Lamp The left or right-hand backup lamp is defective.
X
Check whether you are permitted to change the bulb yourself
(Y page 130).
or
X Visit a qualified specialist workshop. b
Check Front Left 
Sidemarker Lamp
 or 
Check Front Right 
Sidemarker Lamp The left or right front side marker lamp is defective.
X
Check whether you are permitted to replace the bulb yourself
(Y page 129).
or
X Visit a qualified specialist workshop. b
Check Rear Left 
Sidemarker Lamp
 or 
Check Rear Right 
Sidemarker Lamp The rear left or right side marker lamp is defective.
X
Check whether you are permitted to change the bulb yourself
(Y page 129).
or
X Visit a qualified specialist workshop. b
Check 
Left Daytime 
Running Light or 
Check Right 
Daytime Running 
Light The left-hand or right-hand daytime running lamp is faulty.
X
Check whether you are permitted to replace the bulb yourself
(Y page 130).
or
X Visit a qualified specialist workshop. b
Active Headlamps 
Inoperative The active light function is defective.
X
Visit a qualified specialist workshop.238
Display messages
On-board computer and displays