Page 248 of 382

Display messages Possible causes/consequences and
0050
0050Solutions 0049
Check Rear Left Check Rear Left
Sidemarker Sidemarker
Lamp Lamp
orCheck Rear
Check Rear
Right Sidemarker
Right Sidemarker
Lamp Lamp The rear left or right side marker lamp is defective.
X
Visit a qualified specialist workshop. 0049
Check Check
Left
LeftDaytime
Daytime
Running
Running
Light Light orCheck
Check
Right Daytime
Right Daytime
Running Light Running Light The left-hand or right-hand daytime running lamp is faulty.
X
Visit a qualified specialist workshop. 0049
Active Headlamps Active Headlamps
Inoperative Inoperative The active light function is defective.
X
Visit a qualified specialist workshop. 0049
Malfunction See Malfunction See
Operator's Manual Operator's Manual The exterior lighting is defective.
X
Visit a qualified specialist workshop. 0049
Malfunction See Malfunction See
Operator's Manual Operator's Manual The exterior lighting is defective.
X
Visit a qualified specialist workshop. 0049
Auto Auto
Lamp
LampFunction
Function
Inoperative
Inoperative The light sensor is defective.
X
Visit a qualified specialist workshop. 0049
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 0058.246
Display
messagesOn-board computer and displays
Page 263 of 382

Display messages Possible causes/consequences and
0050
0050Solutions 00AF
Key Not Detected Key Not Detected
(white display
message) The KEYLESS-GO key cannot be detected at present.
X
Change the location of the SmartKey with the KEYLESS-GO
functions in the vehicle.
If the KEYLESS-GO key is still not detected:
X Operate the vehicle with the SmartKey in the ignition lock. 00AF
Key Detected in Key Detected in
Vehicle Vehicle The KEYLESS-GO key has been detected inside the vehicle during
locking.
X
Remove the KEYLESS-GO key from the vehicle. 00AF
Remove 'Start' Remove 'Start'
Button and Insert Button and Insert
Key Key The KEYLESS-GO key can continuously not be detected.
KEYLESS-GO is temporarily malfunctioning or is defective. A
warning tone also sounds.
X
Insert the SmartKey into the ignition lock and turn it to the
desired position.
X Visit a qualified specialist workshop. 00AF
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. Warning and indicator lamps in the instrument cluster
Seat belts
Problem Possible causes/consequences and
0050 0050Solutions 00E9
After starting the
engine, the red seat
belt warning lamp lights
up for 6 seconds.
The seat belt warning lamp reminds the driver and front passenger
to fasten their seat belts.
X
Fasten your seat belt (Y page 58).00E9
After starting the
engine, the red seat
belt warning lamp lights
up. In addition, a
warning tone sounds
for up to six seconds.
The driver's seat belt is not fastened.
X
Fasten your seat belt (Y page 58).
The warning tone ceases. Wa
rning and indi cator lamps in the instrument cluster
261On-board computer and displays Z
Page 264 of 382

Problem Possible causes/consequences and
0050
0050Solutions 00E9
The red seat belt
warning lamp lights up
after the engine starts,
as soon as the driver's
or the front-passenger
door is closed.
The driver or front passenger has not fastened their seat belt.
X
Fasten your seat belt (Y page 58).
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. 00E9
The red seat belt
warning lamp flashes
and an intermittent
audible warning
sounds.
The driver or front passenger has not fastened their seat belt. The
car is being driven faster than 15 mph (25 km/h) or has briefly
been driven faster than 15 mph (25 km/h).
X
Fasten your seat belt (Y page 58).
The warning lamp goes out and the intermittent warning tone
ceases. There are objects on the front-passenger seat. The car is being
driven faster than 15 mph (25 km/h) or has briefly been driven
faster than 15 mph (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. 262
Warning and indicator lamps in the instrument clusterOn-board computer and displays
Page 270 of 382

Engine
Problem Possible causes/consequences and
0050
0050Solutions 00B9
The yellow Check
Engine warning lamp
lights up while the
engine is running.
There may be a malfunction, for example:
R
in the engine management
R in the fuel injection system
R in the exhaust system
R in the ignition system
R in the fuel system
The emission limit values may be exceeded and the engine may
be in emergency mode.
X Have the vehicle checked as soon as possible at a qualified
specialist workshop.
i In some states, you must immediately visit a qualified
specialist workshop as soon as the yellow Check Engine warning
lamp lights up. This is due to the legal requirements in effect in
these states. If in doubt, check whether such legal regulations
apply in the state in which you are currently driving. 00B6
The yellow reserve fuel
warning lamp flashes
while the vehicle is in
motion. In addition,
the
00B9 Check Engine
warning lamp may light
up. The fuel system pressure is too low. The fuel filler cap is not closed
correctly or the fuel system is leaking.
X Observe the additional display messages in the multifunction
display.
X Check that the fuel filler cap is correctly closed.
X If the fuel filler cap is not correctly closed: close the fuel filler
cap.
X If the fuel filler cap is closed: visit a qualified specialist
workshop. 00B6
The yellow reserve fuel
warning lamp lights up
while the engine is
running.
The fuel level has dropped into the reserve range.
X
Refuel at the nearest gas station. 268
Warning and indicator lamps in the instrument clusterOn-board computer and displays
Page 271 of 382
Problem Possible causes/consequences and
0050
0050Solutions 00AC
The red coolant
warning lamp lights up
while the engine is
running and the coolant
temperature gauge is
at the start of the scale.
The temperature sensor for the coolant temperature gauge is
defective.
The coolant temperature is no longer being monitored. There is a
risk of engine damage if the coolant temperature is too high.
X
Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions. Do not continue
driving under any circumstances.
X Secure the vehicle against rolling away (Y page 164).
X Consult a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
269On-board computer and displays Z
Page 273 of 382

Problem Possible causes/consequences and
0050
0050Solutions X
Make sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.
X Check the coolant level and add coolant (Y page 304). Observe
the warning notes.
X If you need to add coolant more often than usual, have the
engine coolant system checked.
X At coolant temperatures below 248 ‡ (120 †) drive to the
nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic. Driving systems
Problem Possible causes/consequences and
0050 0050Solutions 00BA
The red distance
warning lamp lights up
while the vehicle is in
motion.
G
WARNING
The distance to the vehicle in front is too small for the speed
selected.
There is a risk of an accident.
X Increase the distance. 00BA
The red distance
warning lamp lights up
while the vehicle is in
motion. A warning tone
also sounds.
G
WARNING
You are approaching a vehicle or a stationary obstacle in your line
of travel at too high a speed.
There is a risk of an accident.
X Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to
brake or take evasive action.
More information about DISTRONIC PLUS (Y page 175) and
PRE-SAFE ®
Brake (Y page 72). Warning and indicator lamps in the instrument cluster
271On-board computer and displays Z
Page 288 of 382
X
Insert the plug of the electronic device into
115 V power socket 0043.
Indicator lamp 0044lights up.
X To switch off: remove the connector from
115 V socket 0043.
Ensure that you do not pull on the cord. 286
FeaturesStowage and features
Page 298 of 382

Programming
Programming buttons
Observe the "Important safety notes"
(Y
page 295). Integrated garage door opener in the rear-view
mirror
Garage door remote control
0083is not part of
the integrated garage door opener.
X The first time before programming, clear
the integrated garage door opener memory
(Y page 298).
X Turn the SmartKey to position 2in the
ignition lock.
X Press and hold one of buttons 0044to0085 on
the integrated garage door opener.
After a short time, indicator lamp 0043lights
up yellow.
i Indicator lamp 0043lights up yellow as soon
as button 0044,0087or0085 is programmed for
the first time. If the selected button has
already been programmed, indicator
lamp 0043will only light up yellow after ten
seconds have elapsed.
X Release button 0044,0087or0085. Indicator
lamp 0043flashes yellow.
X Point garage door remote control 0083
towards buttons 0044to0085 on the rear-view
mirror at a distance of 2 to 8 inches (5 to
20 cm).
i The required distance between remote
control 0083and the integrated garage door
opener depends on the garage door drive
system. Several attempts might be necessary. You should test every position
for at least 25 seconds before trying
another position.
X Press and hold button 0084on remote control
0083 until indicator lamp 0043lights up green.
If indicator lamp 0043lights up green or
flashes, then programming has been
successful.
X Release button 0084on remote control 0083for
the garage door drive system.
X If indicator lamp 0043lights up red: repeat
the programming procedure for the
corresponding button on the rear-view
mirror. When doing so, vary the distance
between remote control 0083and the rear-
view mirror.
i If the indicator lamp flashes green after
successful programming, the garage door
system is using a rolling code. After
programming, you must synchronize the
garage door opener integrated in the rear-
view mirror with the receiver of the garage
door system.
Synchronizing the rolling code
Observe the "Important safety notes"
(Y page 295).
Your vehicle must be within reach of the
garage door or exterior gate drive. Make sure
that neither your vehicle nor any persons/
objects are present within the sweep of the
door or gate.
X Turn the SmartKey to position 2in the
ignition lock.
X Press the program button of the door or
gate drive (see the door or gate drive
operating instructions, e.g. under
"programming of additional remote
controls"). 296
FeaturesStowage and features