Display messages
Possible causes/consequences and
M
MSolutions DISTRONIC
DISTRONIC
PLUS
PLUScur‐
cur‐
rently
rently unavailable
unavailable
See Owner's Manual
See Owner's Manual DISTRONIC PLUS is temporarily inoperative.
Possible causes:
R the function is impaired due to heavy rain or snow
R the sensors in the radiator trim and 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 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
A warning tone also sounds.
Once the causes listed above no longer apply, the display message goes out.
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 to prevent it from rolling away (Y page 180).
X Clean the sensors in the radiator grille and the bumper
(Y page 337).
X Restart the engine. DISTRONIC PLUS DISTRONIC PLUS
inoperative inoperative DISTRONIC PLUS is faulty.
The following may have also failed:
R BAS PLUS
R PRE-SAFE ®
Brake
A warning tone also sounds.
X Visit a qualified specialist workshop. DISTRONIC DISTRONIC
PLUS
PLUSsus‐
sus‐
pended
pended 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
DISTRONIC PLUS
- - - km/h - - - km/h An activation condition for DISTRONIC PLUS is not fulfilled.
X Check the activation conditions for DISTRONIC PLUS
(Y page 191). DISTRONIC
DISTRONIC
PLUS
PLUSand
and
SPEEDTRONIC inop‐
SPEEDTRONIC inop‐
erative erative DISTRONIC PLUS and SPEEDTRONIC are faulty.
A warning tone also sounds.
X Visit a qualified specialist workshop. 278
Display
messagesOn-board computer and displays
Display messages
Possible causes/consequences and
M
MSolutions Without changing
Without changing
gear, gear,
consult workshop consult workshop You cannot change the transmission position due to a malfunction.
A warning tone also sounds.
If transmission position Dis selected:
X Drive to a qualified specialist workshop without shifting the
transmission from position D.
If transmission position R,Nor Pis selected:
X Consult a qualified specialist workshop. Only select Park Only select Park
(P) (P)
when vehicle is when vehicle is
stationary stationary The vehicle is moving.
X
Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Shift the transmission to position P.N CLS Coupé: the boot lid is open.
X Close the boot lid. A CLS Shooting Brake: the tailgate is open.
G WARNING
When the engine is running, exhaust gases can enter the vehicle
interior if the tailgate is open.
There is a risk of poisoning.
X Close the tailgate. Mor
? The bonnet is open. A warning tone also sounds.
G WARNING
The open bonnet may then block your view when the vehicle is in
motion.
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.
X Secure the vehicle to prevent it from rolling away (Y page 180).
X Close the bonnet. C At least one door is open. A warning tone also sounds.
X Close all doors. Display
messages
283On-board computer and displays Z
Display messages
Possible causes/consequences and
M
MSolutions _
Rear left seat Rear left seat
backrest not backrest not
locked locked
orRear
Rear
right seat back‐
right seat back‐
rest not locked rest not locked The backrest in the rear is not engaged on the left-hand and/or
right-hand side. A warning tone also sounds.
X Push the backrest back until it engages. _
Front left seat Front left seat
backrest not backrest not
locked locked
orFront
Front
right seat back‐
right seat back‐
rest not locked rest not locked The driver's or front-passenger seat backrest is not engaged. A
warning tone also sounds.
X Push the backrest back until it engages. j
Check trailer Check trailer
hitch lock hitch lock The trailer tow hitch is not correctly engaged.
A warning tone also sounds.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Apply the parking brake.
X Engage the trailer coupling's ball coupling in the end position
(Y page 234). &
inoperative Bat‐ inoperative Bat‐
tery low tery low The on-board voltage is too low. The auxiliary heating has switched
itself off or cannot be switched on (Y page 150).
X Drive for a considerable distance.
The battery charges. The auxiliary heating is operational again as
soon as the on-board electrical system voltage is sufficient. &
inoperative inoperative
Refuel
Refuel
vehicle
vehicle There is too little fuel in the fuel tank. The auxiliary heating cannot
be switched on (Y page 150).
X Refuel at the nearest filling station. &
inoperative See inoperative See
Owner's Man. Owner's Man. The auxiliary heating has a temporary malfunction or is faulty.
X When the vehicle is on a level surface and the engine has cooled
down, make up to four attempts to switch on the auxiliary heat- ing, waiting several minutes between each attempt
(Y page 150).
X If the auxiliary heating does not switch on, consult a qualified
specialist workshop. 284
Display
messagesOn-board computer and displays
Display messages
Possible causes/consequences and
M
MSolutions Â
Key not detected Key not detected
(red display message) The KEYLESS-GO key is not in the vehicle.
A warning tone also sounds.
If the engine is switched off, you can no longer lock the 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 Secure the vehicle against rolling away (Y page 180).
X Locate the KEYLESS-GO key. The KEYLESS-GO key is not detected while the engine is running
because there is interference from a strong source of radio waves.
A warning tone also sounds.
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 180).
X Operate the vehicle with the key in the ignition lock if necessary. Â
Key not detected 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. Â
Key still in vehi‐ Key still in vehi‐
cle cle The KEYLESS-GO key has been detected inside the vehicle during
locking.
X Remove the KEYLESS-GO key from the vehicle.
X Lock the vehicle again. Â
Remove starting Remove starting
button, then button, then
insert key insert key The KEYLESS-GO key is not continually detected.
KEYLESS-GO is temporarily malfunctioning or is defective. A warn-
ing tone also sounds.
X Insert the key into the ignition lock and turn it to the desired
position.
X Visit a qualified specialist workshop. Â
Close doors to Close doors to
lock vehicle lock vehicle At least one door is open. A warning tone also sounds.
X Close all doors and lock the vehicle again. 286
Display
messagesOn-board computer and displays
Warning and indicator lamps in the instrument cluster
Safety
Seat belts Problem
Possible causes/consequences and
M
MSolutions ü
Only for certain coun-
tries: the red seat belt
warning lamp lights up
for 6 seconds after the
engine starts.
The seat belt warning lamp reminds the driver and front passenger
to fasten their seat belts.
X Fasten your seat belt (Y page 46).ü
Only for certain coun-
tries: the red seat belt
warning lamp lights up
after the engine starts.
In addition, a warning
tone sounds for up to
6 seconds.
The driver's seat belt is not fastened.
X Fasten your seat belt (Y page 46).
The warning tone ceases. ü
The red seat belt warn-
ing lamp lights up after
the engine starts, as
soon as the driver's or
the front-passenger
door is closed.
The driver or passenger has not fastened their seat belt.
X Fasten your seat belt (Y page 46).
The warning lamp goes out. There are objects on the front-passenger seat.
X Remove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out. ü
The red seat belt warn-
ing lamp flashes and an
intermittent audible
warning sounds. The driver or passenger has not fastened their seat belt. At the
same time, you are driving faster than 25 km/h or have briefly
driven faster than 25 km/h.
X Fasten your seat belt (Y page 46).
The warning lamp goes out and the intermittent warning tone
ceases. There are objects on the front-passenger seat. At the same time,
you are driving faster than 25 km/h or have briefly driven faster
than 25 km/h.
X Remove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out and the intermittent warning tone
ceases. Warning and indicator lamps in the instrument cluster
287On-board computer and displays Z
Safety systems
Problem
Possible causes/consequences and
M
MSolutions J
The yellow brake sys-
tem warning lamp
lights up while the
engine is running.
G
WARNING
The brake system is malfunctioning and the braking characteris-
tics may be affected.
There is a risk of an accident.
X If the multifunction display shows a display message, please
observe this.
X Drive on carefully.
X Visit a qualified specialist workshop. J
The red brake system
warning lamp comes on
while the vehicle is
moving. A warning tone
also sounds. You are driving with the parking brake applied.
X Release the parking brake.
The warning lamp goes out and the warning tone ceases. J
The red brake system
warning lamp is lit while
the engine is running. A
warning tone also
sounds. G
WARNING
The brake boosting effect is malfunctioning and the braking char- acteristics may be affected.
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 180).
X Consult a qualified specialist workshop.
X Observe the additional display messages in the multifunction
display. 288
Warning and indicator lamps in the instrument clusterOn-board computer and displays
Problem
Possible causes/consequences and
M
MSolutions J
The red brake system
warning lamp is lit while
the engine is running. A
warning tone also
sounds. There is insufficient brake fluid in the brake fluid reservoir.
G WARNING
Braking efficiency 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 180).
X Do not top up the brake fluid. Topping up will not rectify the fault.
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) has been deactivated due to a fault.
Therefore, BAS (Brake Assist System), BAS PLUS, ESP ®
(Electronic
Stability Program), PRE ‑SAFE®
, PRE‑SAFE ®
Brake, the HOLD func-
tion, hill start assist, ESP ®
trailer stabilisation and the adaptive
brake lights, for example, are also deactivated.
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 affec-ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of 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 trans-
mission, will be unavailable. Warning and indicator lamps in the instrument cluster
289On-board computer and displays Z
Problem
Possible causes/consequences and
M
MSolutions !
The yellow ABS warning
lamp is lit while the
engine is running. ABS is temporarily unavailable. Therefore, BAS, BAS PLUS, ESP
®
,
EBD (electronic brake force distribution), PRE‑ SAFE®
,
PRE‑SAFE ®
Brake, the HOLD function, hill start assist, ESP ®
trailer
stabilisation and the adaptive brake lights, for example, are also
deactivated.
Possible causes:
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, for example, if you brake hard.
The steerability and braking characteristics may be severely affec-ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is a risk of an accident.
X Carefully drive on a suitable stretch of road, making slight steer-
ing movements at a speed above 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. 290
Warning and indicator lamps in the instrument clusterOn-board computer and displays