
Display messages Possible causes/consequences and
M Solutions
PRE-SAFE
Functions cur‐
rently limited See
Owner's Manual G
Risk of accident
PRE-SAFE ®
Brake is temporarily inoperative. Possible causes:
R the DISTRONIC PLUS cover in the radiator grille is dirty.
R function is impaired due to heavy rain or snow.
R the sensors in the bumpers are dirty.
R the rada rsensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation.
R AMG vehicles: ESP ®
is inactive.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
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 Engage the electric parking brake.
X Clean the DISTRONIC PLUS cover in the radiator grille
(Y page 257).
X Clean the bumpers (Y page 257).
X Restart the engine.
X AMG vehicles: reactivate ESP ®
(Y page 57).
If the system detects that the sensors are fully operational, the
display message disappears.
PRE-SAFE ®
Brake is operational again. PRE-SAFE
Functions limited
See Owner's Manual G
Risk of accident
PRE-SAFE ®
Brake is faulty. BASP LUS or the distance warning sig-
nal may also have failed.
X Visit a qualified specialist workshop. 6
Restraint
sys. mal‐
function Consult
workshop G
Risk of injury
There is a malfunction in the SRS (Supplemental Restraint Sys-
tem). The 6warning lamp also lights up in the instrument clus-
ter.
X Visit a qualified specialist workshop. Display messages
207On-board computer and displays Z 

Driving systems
Display messages Possible causes/consequences and
M Solutions
À
Attention Assist:
Drowsiness detec‐
ted Based on specific criteria, ATTENTION ASSIST has determined that
the driver is tired or paying less attention
.Awarning 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 has failed.
X
Visi taqualified specialist workshop. Speed Limit Assist
currently unavail‐
able See Owner's
Manual Speed Limit Assist is deactivated and temporarily inoperative.
Possible causes:
R
the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
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 Engage the electric parking brake.
X Clean the windscreen.
If the system detects that the camera is fully operational, the dis-
play message disappears.
Speed Limit Assist is operational again. Speed Limit Assist:
Unavailable in
this country Speed Limit Assist is only available in certain countries.
X
Drive on.
Speed Limit Assist is available again when you drive in a country
in which its use is approved. Speed Limit Assist
inoperative Speed Limit Assist is faulty.
X
Visit a qualified specialist workshop. ë
Off The HOLD function is deactivated. the vehicle is skidding.
Aw
arning tone also sounds.
X Reactivate the HOLD function later (Y page 165). Display messages
213On-board computer and displays Z 

Display messages Possible causes/consequences and
M Solutions
The HOLD function is deactivated. Whe
nthe brake pedal is firmly
depressed, an activation condition is not fulfilled.
Aw arning tone also sounds.
X Check the activation conditions for the HOLD function
(Y page 165). Radar sensor deac‐
tivated autom. See
Owner's Manual Vehicles with a navigation system: the vehicle is close to a radio
telescope facility and is therefore prohibited from transmitting any
radar signals. The radar sensor system has switched off automat-
ically (Y
page 312).
DISTRONI CPLUS (Y page 156) is deactivated automatically if it is
activated. Awarning tone also sounds.
BAS PLUS (Brake Assist PLUS) (Y page 54)and PRE-SAFE ®
Brake
(Y page 59) are then also not available.
X Drive on.
Once you have moved fa renough away from the radio telescope,
the above functions are available again. Vehicles with Becker
®
MAP PILOT: if the Becker ®
MAP PILOT is
not connected, the rada rsensor system is deactivated automati-
cally.
BAS PLUS, DISTRONIC PLUS and PRE-SAFE ®
Brake are not avail-
able.
X Connect the Becker ®
MAP PILOT; see the separate operating
instructions. Radar sensor
deactivated See
Owner's Manual The radar sensor system is deactivated.
X
Check whether or not the radar sensor system may be activated
(Y page 312).
X Switch on the radar sensor system (Y page 194).Parking Guidance
inoperative Parking Guidance is malfunctioning (
Ypage 170).
X Restart the engine.
If the display message continues to be displayed:
X Visit a qualified specialist workshop. 214
Display messagesOn-board computer and displays 

Display messages Possible causes/consequences and
M Solutions
DISTRONIC PLUS
currently unavail‐
able See Owner's
Manual DISTRONIC is deactivated and temporarily inoperative. Possible
causes:
R
the DISTRONIC PLUS cover in the radiator grille is dirty.
R function is impaired due to heavy rain or snow.
R the sensors in the bumpers are dirty.
R the rada rsensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation.
R the system is outside the operating temperature range.
R The on-board voltage is too low.
Aw arning tone also sounds.
If the display message does no tdisappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Engage the electric parking brake.
X Clean the DISTRONIC PLUS cover in the radiator grille
(Y page 257).
X Clean the bumpers (Y page 257).
X Restar tthe 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 faulty. BAS PLUS and PRE-SAFE
®
Brake may
also have failed.
Aw arning tone also sounds.
X Visi taqualified specialist workshop. DISTRONIC PLUS
override 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
--- km/h An activation condition for DISTRONIC PLUS is not fulfilled.
X
Check the activation conditions for DISTRONIC PLUS
(Y page 156). DISTRONIC PLUS and
SPEEDTRONIC
inoperative DISTRONIC PLUS and SPEEDTRONIC are faulty. A warning tone
also sounds.
X
Visit a qualified specialist workshop. 216
Display messagesOn-board computer and displays 

Vehicle
Display messages Possible causes/consequences and
M Solutions
To start engine,
shift to either P
or N You have attempted to start the engine with the transmission in
position
Ror D.
X Shift the transmission to position Por N. P
Select Park (P) A malfunction has occurred while the HOLD function or DIS-
TRONIC PLUS is active.
At
one may also sound at regular intervals. The tone becomes
louder if you attempt to lock the vehicle.
You cannot start the engine.
X Shift the transmission to position P.
You can restart the engine. N The boot lid is open.
X
Close the boot lid. M G
Risk of accident
The bonnet is open. Awarning tone also sounds.
X Pull ove rand stop the vehicle safely as soo nas possible, paying
attention to road and traffic conditions.
X Engage the electric parking brake.
X Close the bonnet. Active bonnet mal‐
function See Own‐
er's Manual The active bonnet (pedestrian protection) is not active due to a
malfunction or because it has already been triggered
(Y
page 248).
X Visit a qualified specialist workshop. C At least one door is open.
Awarning tone also sounds.
X Close all doors. J
Close boot separa‐
tor The boot separato
ris open.
X Close the boot separator (Y page 80).220
Display messagesOn-board computer and displays 

Display messages Possible causes/consequences and
M Solutions
The roo
fhas been opened and closed several times in arow. The
roof drive has been switched off automatically for safety reasons.
You can open and close the roof again after approximately
10 minutes.
X Switch off the ignition and turn it back on.
X Repeat the opening or closing procedure (Y page 79).¥
Top
up washer fluid The washer fluid level in the washer fluid reservoir has dropped
below the minimum.
X
Top up the washer fluid (Y page 252).Key
Display messages Possible causes/consequences and
M Solutions
+
Key does not
belong to vehicle You have put the wrong key in the ignition lock.
X
Use the correct key. +
Replace key The key needs to be replaced.
X
Visit a qualified specialist workshop. +
Change key batter‐
ies The batteries of the KEYLESS-GO key are discharged.
X
Change the batteries (Y page 68).+
Key not detec‐
ted (red display mes-
sage) The KEYLESS-GO key is not in the vehicle.
Aw
arning tone also sounds.
If the engine is switched off, you can no longer loc kthe 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 Engage the electric parking brake.
X Locate the KEYLESS-GO key. 222
Display messagesOn-board computer and displays 

Display messages Possible causes/consequences and
M Solutions
The KEYLESS-GO key is no
tdetected while the engine is running
because there is interference from a strong source of radio waves.
Aw arning tone also sounds.
X Pull ove rand stop the vehicle safely as soo nas possible, paying
attention to road and traffic conditions.
X Engage the electric parking brake.
X Operate the vehicle with the key in the ignition lock if necessary. +
Key not detected
(White display mes-
sage) The KEYLESS-GO key cannot be detected at present.
X
Change the location of the key with the KEYLESS-GO functions
in the vehicle.
If the KEYLESS-GO key is still not detected:
X Operate the vehicle with the key in the ignition lock if necessary. +
Key still in vehi‐
cle The KEYLESS-GO key has been detected inside the vehicle during
locking.
X
Remove the KEYLESS-GO key from the vehicle. +
Remove starting
button, then
insert key KEYLESS-GO is temporarily malfunctioning or is defective.
Awarn-
ing tone also sounds.
X Insert the key into the ignition lock and turn it to the desired
position.
X Visi taqualified specialist workshop. +
Close doors to
lock vehicle At least one door is open.
Awarning tone also sounds.
X Close all doors and loc kthe vehicle again. Display messages
223On-board computer and displays Z 

Safety systems
Problem Possible causes/consequences and
M Solutions
J
The red brake system
warning lamp comes on
while the engine is run-
ning. A warning tone
also sounds.
G
Risk of accident
There is insufficient brake fluid in the fluid reservoir.
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 Engage the electric parking brake.
X Consult a qualified specialist workshop immediately.
X Observe the additional display messages in the multifunction
display.
Do not top up the brake fluid. This does not correct the error. !
The yellow ABS warning
lamp is lit while the
engine is running. G
Risk of accident
ABS (Anti-lock Brake System) has been deactivated due to a fault.
For this reason, BAS (Brake Assist), BAS PLUS, ESP ®
(Electronic
Stability Program), PRE-SAFE ®
,P RE-SAFE ®
Brake ,the HOLD func-
tion, hill start assist and the adaptive brake lights are also deac-
tivated, for example.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
ATTENTION ASSIST is deactivated.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. 226
Warning and indicator lamps in the instrument clusterOn-board computer and displays