2016 MERCEDES-BENZ CLA COUPE ECU

Display messages
Possible causes/consequences and
M
MSolutions !
Parking brake inop‐ Parking brake inop‐
erative erative The yellow
!warning lamp lights up. The red !indicator lamp
flashes for about ten seconds after the electric parking brake has been applied or released. It then goes out or remains lit.
The electric parking brake is malfunctioning, e.g. because of over-
voltage or undervoltage.
X Rectify the cause of the overvoltage or undervoltage, e.g. by charg-
ing the battery or restarting the engine.
X Apply or release the electric parking brake.
If the electric parking brake still cannot be applied or released: X Turn the ignition off and then back on.
X Apply or release the electric parking brake.
If the electric parking brake still cannot be released:
X Consult a qualified specialist workshop.
If the electric parking brake still cannot be applied:
X Consult a qualified specialist workshop. The red
!indicator lamp flashes and the yellow !warning lamp
is lit.
The electric parking brake cannot be applied manually.
X Vehicles with manual transmission: engage first gear.
X Vehicles with automatic transmission: shift the transmission to
position P.
X Consult a qualified specialist workshop. J
Brake immediately Brake immediately Vehicles with manual transmission: a malfunction has occurred while
the HOLD function was activated.
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 155).
You can restart the engine. 222
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions J
Check brake fluid Check brake fluid
level level There is insufficient brake fluid in the brake fluid reservoir.
In addition, the red Jwarning lamp lights up on the instrument
cluster and a warning tone sounds.
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.
X Secure the vehicle against rolling away (Y page 155).
X Consult a qualified specialist workshop.
X Do not top up the brake fluid. This does not correct the fault. #
Check Check
brake
brakepad
padwear
wear The brake pads/linings have reached their wear limit.
X Consult a qualified specialist workshop. G
Inoperative
Inoperative One or more main features of the Mercedes-Benz Contact system are
malfunctioning.
X Consult a qualified specialist workshop. Active
Active
Brake
BrakeAssist
Assist
Functions
Functions currently
currently
limited
limited See
SeeOwner's
Owner's
Manual
Manual Active Brake Assist is temporarily inoperative.
Possible causes:
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.
Once the causes listed above no longer apply, the display message
goes out.
Active Brake Assist is operational again.
If the display message does not disappear:
X Stop the vehicle, paying attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 155).
X Restart the engine. Active Brake Active Brake
Assist: Assist:
System
Systeminop‐
inop‐
erative
erative Active Brake Assist is unavailable due to a malfunction. The situation-
dependent braking assistance function may also have failed.
X Consult a qualified specialist workshop immediately. PRE-SAFE inopera‐
PRE-SAFE inopera‐
tive See Owner's tive See Owner's
Manual Manual
Important PRE-SAFE
®
functions have failed. All other occupant safety
systems, e.g. airbags, remain available.
X Consult a qualified specialist workshop immediately. Display
messages
223On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions Radar
Radar
sensors
sensors dirty
dirty
See Owner's Manual
See Owner's Manual The radar sensor system is malfunctioning.
Possible causes:
R Dirt on sensors
R Heavy rain or snow
R Driving on inter-urban roads without traffic or infrastructure, e.g. in
desert-like areas
At least one driving system or driving safety system is malfunctioning
or is temporarily unavailable:
R Active Brake Assist
R Distance Pilot DISTRONIC
A warning tone also sounds.
Once the cause of the problem is no longer present, the driving and
driving safety systems will be available again. The display message
disappears.
If the display message does not disappear:
X Stop the vehicle, paying attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 155).
X Switch off the engine.
X Clean all sensors (Y page 289).
X Restart the engine.
The display message disappears. ü If this symbol appears in the multifunction display, a seat belt tongue
has been inserted into a rear seat belt buckle.
Further information on the status indicator for the rear seat belts
(Y page 44). ý If this symbol appears in the multifunction display, a seat belt tongue
has not been inserted in a rear seat belt buckle.
G WARNING
A seat belt which is not worn correctly, or which has not been engaged
in the seat belt buckle correctly, cannot provide the intended level of protection.
This poses an increased risk of injury.
X If necessary, ask the occupants in the rear to fasten their seat belts
(Y page 43).
Further information on the status indicator for the rear seat belts
(Y page 44). 224
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions Front-passenger
Front-passenger
airbag airbag
disabled
disabled See
See
Owner's Manual
Owner's Manual The front-passenger front airbag is disabled during the journey
although:
R an adult
or
R a person of the corresponding stature is on the front-passenger seat
If additional forces are applied to the seat, the weight the system
detects may be too low.
G WARNING
The front-passenger front airbag does not deploy during an accident.
This poses 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 155).
X Switch the ignition off.
X Have the occupant on the front-passenger seat step out of the
vehicle.
X Make sure that the seat is unoccupied, close the front-passenger
door and switch on the ignition.
X Observe the PASSENGER AIR BAG indicator lamps in the centre
console and the multifunction display and check the following:
Seat unoccupied and ignition switched on:
R A self-diagnosis is carried out. The PASSENGER AIR BAG OFF and
PASSENGER AIR BAG ON indicator lamps light up simultaneously
for approximately six seconds
R The PASSENGER AIR BAG OFF indicator lamp must then light up
and remain lit after the self-diagnosis. If the indicator lamp is on,
the automatic front-passenger front airbag deactivation system
has disabled the front-passenger front airbag (Y page 47)
R The Front-passenger airbag enabled See Owner's Man‐
Front-passenger airbag enabled See Owner's Man‐
ual ual orFront-passenger airbag disabled See Owner's
Front-passenger airbag disabled See Owner's
Manual
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 on the multi-
function display.
If these conditions are met, the front-passenger seat can be occupied again. Whether the PASSENGER AIR BAG OFF or ON indicator lamp
remains lit or goes out depends on how the automatic front-passenger front airbag deactivation system classifies the occupant.
If the conditions are not met, the system is not operating correctly.
X Consult a qualified specialist workshop immediately.
Further information on the automatic front-passenger front airbag
deactivation feature (Y page 47).226
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions Front-passenger
Front-passenger
airbag enabled See airbag enabled See
Owner's Manual Owner's Manual The front-passenger front airbag is enabled during the journey
although:
R a child, a small adult or an object weighing less than the system
weight threshold is located on the front-passenger seat
or
R the front-passenger seat is not occupied
The system may detect objects or forces that are placing additional
weight on the seat.
G WARNING
The airbag may deploy unintentionally.
This poses 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 155).
X Switch the ignition off.
X Open the front-passenger door.
X Remove the child and child seat from the front-passenger seat.
X Make sure that no objects are present that are applying additional
weight to the seat.
The system might otherwise detect the additional weight and inter-pret the seat occupant's weight as greater than it actually is.
X Make sure that the seat is unoccupied, close the front-passenger
door and switch on the ignition.
X Observe the PASSENGER AIR BAG indicator lamps in the centre
console and the multifunction display and check the following:
Seat unoccupied and ignition switched on:
R A self-diagnosis is carried out. The PASSENGER AIR BAG OFF and
PASSENGER AIR BAG ON indicator lamps light up simultaneously
for approximately six seconds
R The PASSENGER AIR BAG OFF indicator lamp must then light up
and remain lit after the self-diagnosis. If the indicator lamp is on,
the automatic front-passenger front airbag deactivation system
has disabled the front-passenger front airbag (Y page 47)
R The Front-passenger airbag enabled See Owner's Man‐
Front-passenger airbag enabled See Owner's Man‐
ual ual orFront-passenger airbag disabled See Owner's
Front-passenger airbag disabled See Owner's
Manual
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 on the multi-
function display.
If these conditions are met, the front-passenger seat can be occupied again. Whether the PASSENGER AIR BAG OFF or ON indicator lamp
remains lit or goes out depends on how the automatic front-passenger
front airbag deactivation system classifies the occupant.
If the conditions are not met, the system is not operating correctly. Display
messages
227On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions b
Reversing light Reversing light The reversing lamp is faulty.
X Check whether you are permitted to replace the bulb yourself
(Y page 111).
or
X Consult a qualified specialist workshop. b
Left tail lamp Left tail lamp
or
Right tail lamp
Right tail lamp The left or right-hand tail lamp is faulty.
X Consult a qualified specialist workshop. b
Left daytime driv‐ Left daytime driv‐
ing lamp ing lamp
orRight
Right
daytime
daytime driving
drivinglamp
lamp The left or right-hand daytime driving lamp is faulty.
X Check whether you are permitted to replace the bulb yourself
(Y page 111).
or
X Consult a qualified specialist workshop. b
Malfunction Malfunction
See
SeeOwn‐
Own‐
er's Manual
er's Manual The exterior lighting is faulty.
X Consult a qualified specialist workshop. Vehicles with trailer tow hitch: a fuse may have blown.
X Stop the vehicle, paying attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 155).
X Check the fuses (Y page 308).
X If necessary, replace the blown fuse. Observe the warning notes as
you do so.
If the multifunction display still shows the display message: X Consult a qualified specialist workshop. b
AUTO lights inoper‐ AUTO lights inoper‐
ative ative The light sensor is faulty.
X
Consult a qualified specialist workshop. b
Switch off lights Switch off lights The lights are still switched on when you leave the vehicle. A warning
tone also sounds.
X Turn the light switch to the Ãposition. b
Switch on headlamps Switch on headlamps You are driving without dipped-beam headlamps.
X
Turn the light switch to the Lorà position. 230
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions ?
Coolant Stop vehi‐ Coolant Stop vehi‐
cle Switch engine cle Switch engine
off off The coolant is too hot.
A warning tone also sounds.
G WARNING
Never drive with an overheated engine. Driving when your engine has
overheated can cause any fluids that may have leaked into the engine compartment to catch fire.
In addition, steam from an overheated engine can cause serious
burns, which can occur just by opening the bonnet.
There is a risk of injury.
X Stop the vehicle immediately, paying attention to road and traffic
conditions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 155).
X Wait until the engine has cooled down.
X Make sure that the air supply to the engine radiator is not blocked,
e.g. by frozen slush.
X Do not start the engine again until the display message goes out and
the coolant temperature is below 120 †. The engine may otherwise be damaged.
X Pay attention to the coolant temperature gauge.
If the temperature increases again:
X Consult a qualified specialist workshop immediately.
Under normal operating conditions and with the specified coolant
level, the coolant temperature may rise to 120 †. #
See Owner's Manual See Owner's Manual The battery is no longer being charged.
A warning tone also sounds.
Possible causes:
R faulty alternator
R torn poly-V-belt
R a malfunction in the electronics
! Do not continue driving. The engine could otherwise overheat.
X Stop the vehicle immediately, paying attention to road and traffic
conditions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 155).
X Consult a qualified specialist workshop. 232
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions #
Stop vehicle See Stop vehicle See
Owner's Manual Owner's Manual The battery is no longer being charged and the battery charge level is
too low.
A warning tone also sounds.
X Stop the vehicle immediately, paying attention to road and traffic
conditions, and switch off the engine.
X Safeguard the vehicle against rolling away (Y page 155).
X Observe the instructions in the #See SeeOwner's
Owner's Manual
Manualdisplay
message.
X Consult a qualified specialist workshop. 4
Check Check
eng.
eng.oil
oillev.
lev.
when
when next
nextrefuelling
refuelling The engine oil level has dropped to the minimum level.
A warning tone also sounds.
! Avoid long journeys when there is too little coolant in the cooling
system. Otherwise the engine will be damaged.
X Check the oil level when next refuelling, at the latest (Y page 282).
X If necessary, top up the engine oil (Y page 283).
If you have to top up the engine oil frequently:
X Contact a qualified specialist workshop and have the engine
checked.
Information on approved engine oils can be obtained from any quali-
fied specialist workshop or on the Internet at http://bevo.mercedes-
benz.co m. 4
Add 1 litre engine Add 1 litre engine
oil when next refu‐ oil when next refu‐
elling elling The engine oil level has dropped to the minimum level.
! Avoid long journeys when there is too little coolant in the cooling
system. Otherwise the engine will be damaged.
X Check the oil level when next refuelling, at the latest (Y page 282).
X If necessary, top up the engine oil (Y page 283).
If you have to top up the engine oil frequently:
X Contact a qualified specialist workshop and have the engine
checked.
Information on approved engine oils can be obtained from any quali-
fied specialist workshop or on the Internet at http://bevo.mercedes-
benz.com. 4
Engine oil level Engine oil level
Stop Stop
vehicle
vehicle Switch
Switch
engine off
engine off The engine oil level is too low. There is a risk of engine damage.
X Stop the vehicle immediately, paying attention to road and traffic
conditions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 155).
X Check the engine oil level (Y page 282).
X If necessary, top up the engine oil (Y page 283). Display messages
233On-board computer and displays Z