
Problems with PARKTRONIC
Problem Possible causes/consequences and
0050
0050Solutions Only the red segments
in the PARKTRONIC
warning displays are lit.
A warning tone also
sounds for approx-
imately 2 seconds.
PARKTRONIC is deacti-
vated after approx-
imately 20 seconds.
The indicator lamp of
the
0069 button lights
up and the red seg-
ments in the
PARKTRONIC warning
display go out. PARKTRONIC has malfunctioned and has switched itself off.
X
If problems persist, have PARKTRONIC checked at a qualified
specialist workshop. The PARKTRONIC
warning displays
implausible distances.
For example, all the
segments may be lit
even though there is no
obstacle present. The PARKTRONIC sensors are dirty or iced up.
X
Clean the PARKTRONIC sensors (Y page 270).
X Turn the key to position 2again in the ignition lock. The license plate or other parts attached near the sensors may
not be secured correctly.
X
Check the license plate and attachment parts near the sensors
for correct seating. An external radio or ultrasonic source may be causing interfer-
ence.
X
Check PARKTRONIC functions in a different location. Rear view camera
Important safety notes !
Objects that are not at ground level
appear further away than they actually are,
for example:
R the bumper of the vehicle parked behind
R the drawbar of a trailer
R the ball coupling of a trailer tow hitch
R the tail-end of a truck
R slanted posts Only use the camera guide lines for orien-
tation. Do not get any closer to objects than
the lowest horizontal guide line. You may
otherwise damage your vehicle and/or the
object.
The rear view camera is only an aid. It cannot
replace your own awareness of the immedi-
ate surroundings. You are responsible for
safe maneuvering and parking. When maneu-
vering and parking, make sure that there are
no persons, animals or objects in the maneu-
vering area. Driving systems
171Driving and parking Z 

Observe the following when towing a trailer:
R Practice driving around bends, stopping
and backing up at a place where there is no
traffic. This enables you to gain experience
and get used to the new handling charac-
teristics.
R Before driving, check:
-that the trailer tow hitch and ball cou-
pling are secure
- that the safety switch for a braked trailer
is functioning properly
- that the safety chains are secure and not
damaged
- that the electrical connections are
secure
- that the lights are working
- that the wheels are in good order and the
tire pressure is correct
R Adjust the exterior mirrors to provide an
unobstructed view of the rear section of the
trailer.
R If the trailer has electronically controlled
brakes, pull the vehicle/trailer combina-
tion away carefully. Brake manually using
the brake controller and check that the
brakes are working.
R Secure the load on the trailer according to
the applicable specifications and current
standards on securing loads
(Y page 244).
R When driving with a trailer, check at regular
intervals that the load is secured and that
the brakes and lights are working.
R Bear in mind that the handling will be less
stable when towing a trailer than when driv-
ing without one. Avoid sudden steering
movements.
R The vehicle/trailer combination is heavier,
accelerates more slowly and has a
decreased gradient climbing capability and
a longer braking distance.
It is more susceptible to crosswinds and
requires cautious steering.
R If possible, do not brake suddenly, but
rather moderately at first so that the trailer can activate its brakes. Then increase the
force on the brake pedal.
R If the automatic transmission repeatedly
shifts between gears when driving on
inclines, restrict the shift range. Select shift
range 4,3,2or 1.
Driving in a low gear and at a low speed
reduces the risk of damaging the engine.
R When driving on a downhill gradient, shift
to a low gear and take advantage of the
engine's braking effect.
Avoid continuous brake application as this
may overheat the vehicle brakes and, if
installed, the trailer brakes.
R If the coolant temperature increases dra-
matically while the air-conditioning system
is switched on, switch off the air-condition-
ing system.
Coolant heat can also be dissipated by
switching the airflow and the temperature
of the heater/air conditioning to the maxi-
mum level. Open the windows if necessary.
R When overtaking, pay particular attention
to the extended length of your vehicle/
trailer combination.
Due to the length of your vehicle/trailer
combination you need an additional dis-
tance before you can return to your original
lane. Uncoupling a trailer
G
WARNING
If you uncouple a trailer with the overrun
brake engaged, you could trap your hand
between the vehicle and the trailer drawbar.
There is a risk of injury.
Do not uncouple a trailer if the overrun brake
is engaged.
! Do not disconnect a trailer with an
engaged overrun brake. Otherwise, your
vehicle could be damaged by the rebound-
ing of the overrun brake. Towing a trailer
177Driving and parking Z 

Useful information
This Operator's Manual describes all models
as well as standard and optional equipment
of your vehicle that were available at the time
of going to print. Country-specific variations
are possible. Note that your vehicle may not
be equipped with all of the described func-
tions. This also applies to systems and func-
tions relevant to safety.
Read the information on qualified specialist
workshops (Y page 26). Important safety notes
G
WARNING
If you are driving and reach through the steer-
ing wheel to operate the adjustment knob,
you could lose control of the vehicle. There is
a risk of an accident and injury.
Only operate the adjustment knobs when the
vehicle is stationary. Do not reach through the
steering wheel when driving. G
WARNING
If you operate information systems and com-
munication equipment integrated in the vehi-
cle while driving, you will be distracted from
traffic conditions. You could also lose control
of the vehicle. There is a risk of an accident.
Only operate the equipment when the traffic
situation permits. If you are not sure that this
is possible, park the vehicle paying attention
to traffic conditions and operate the equip-
ment when the vehicle is stationary. G
WARNING
If the instrument cluster has failed or mal-
functioned, you may not recognize function
restrictions in systems relevant to safety. The
operating safety of your vehicle may be
impaired. There is a risk of an accident.
Drive on carefully. Have the vehicle checked
at a qualified specialist workshop immedi-
ately. If uncertainties regarding the operating safety
of the vehicle arise when continuing the jour-
ney, stop the vehicle, paying attention to road
and traffic conditions. Instrument cluster
Overview
0043
Instrument cluster on vehicles without
steering wheel buttons
0044 Instrument cluster in vehicles with steer-
ing-wheel buttons
0087 0074/0075 adjustment button, 0079menu but-
ton, 0045reset button, 0098service button
(engine oil level check)
You will find a full overview of the instrument
cluster in the "At a glance" section
(Y page 34).
The display in the instrument cluster is acti-
vated when you:
R open the driver's door
R turn the key to position 2in the ignition lock
R press the 0045reset button
R switch on the lights
The display switches off automatically after
approximately 30 seconds if:
R the vehicle lighting is not switched on.
R the key is in position 0in the ignition lock. 182
Instrument clusterOn-board computer and displays 

Instrument lighting
When the lights are switched on, you can
adjust the brightness of the instrument clus-
ter lighting using the 0074and 0075buttons.
X To brighten: press the0074button.
X To dim: press the 0075button.
i Vehicles with automatic headlamp mode:
the instrument lighting also adapts to auto-
matic headlamp mode. Tachometer
! Do not drive in the overrevving range, as
this could damage the engine. H
Environmental note
Avoid driving at high engine speeds. This
unnecessarily increases the fuel consumption
of your vehicle and harms the environment as
a result of increased emissions.
The red band in the tachometer indicates the
engine's overrevving range.
To protect the engine, the fuel supply is inter-
rupted when the red band is reached. Outside temperature
You should pay special attention to road con-
ditions when temperatures are around the
freezing point.
On vehicles without steering wheel buttons
(Y page 184) and on vehicles with steering
wheel buttons (Y page 189), the outside tem-
perature display is in the display.
Changes in the outside temperature are dis-
played after a short delay. Speedometer
The speed can also be shown in the display.
You can find information on the digital speed-
ometer for vehicles without steering wheel
buttons under (Y page 184) and for vehicles with steering wheel buttons under
(Y
page 189).
i In some countries, a warning sounds
when the vehicle reaches the maximum
speed limit, e.g. at 75 mph ( 120 km/h). Trip odometer
X To reset: make sure that the display is
showing the trip odometer if you have a
vehicle with steering wheel buttons
(Y page 189).
X Press and hold the 0045reset button until the
trip odometer is reset to 0.0 0.0. Fuel gage
0043
Fuel gage on vehicles without steering
wheel buttons
0044 Fuel gage on vehicles with steering wheel
buttons
0087 Fuel filler flap location indicator 007F: the
fuel filler flap is on the left-hand side. Fuel
filler flap location indicator 0080: the fuel
filler flap is on the right-hand side
0085 Reserve fuel warning lamp (Y page 227) Instrument cluster
183On-board computer and displays Z 

Display messages Possible causes/consequences and
0050
0050Solutions flashes for 5 seconds, the
00B0indicator lamp also flashes and
then lights up constantly.
Lane Keeping Assist is deactivated and temporarily inoperative.
Possible causes are:
R There are no lane markings present.
R The camera's functionality is impaired due to heavy rain, snow
or fog.
R The camera cannot recognize the road markings:
- It is too dark.
- The lane markings are worn or are covered, for example, by
dirt or snow.
R The windshield is dirty in the camera's field of vision.
X Stop the vehicle paying attention to road and traffic conditions.
X Secure the vehicle to prevent it from rolling away
(Y page 151).
X Clean the windshield (Y page 269), particularly in the camera's
field of vision.
If the 00B0 indicator lamp goes out, Lane Keeping Assist is
operational again.
If the problem persists, visit a qualified specialist workshop. 0099
dEF Chk dEF Chk In addition, the yellow
00B9Check Engine indicator lamp and the
yellow 00E2DEF indicator lamp light up and a warning tone
sounds.
The DEF reducing agent is contaminated, diluted or is not compli-
ant with ISO 22241.
After the first message and under normal operating conditions,
you can drive on for up to approximately 50 miles (80 km). Then
a warning tone sequence sounds and the engine can only be
started another 16 times.
X Have the DEF tank cleaned and refilled at a qualified specialist
workshop as soon as possible. 202
Display
messagesOn-board computer and displays 

Display messages Possible causes/consequences and
0050
0050Solutions 0099
dEF Chk dEF Chk In addition, the yellow
00E2DEF indicator lamp lights up and a
warning tone sounds.
The DEF supply has dropped below 1.5 US gal (5.5 l).
After the message appears for the first time, and under normal
driving conditions, the remaining DEF supply will last for approx-
imately 1000 miles (1600 km).
After that, the 0.8 US gal (3.0 l) reserve mark is reached. A warning
tone sequence sounds and the engine can then only be started
another 16 times.
X add DEF supply (Y page 149).
The 00E2 DEF indicator lamp disappears after no more than
20 seconds after the vehicle has stopped or you have switched
on the ignition or started the engine after refueling. 0099
StArtS RExx StArtS RExx In addition, the yellow
00B9Check Engine indicator lamp and the
yellow 00E2DEF indicator lamp light up and a warning tone
sounds. A warning tone sequence sounds.
After the message appears for the first time, the engine can only
be started another 16 times.
The number of remaining engine starts XX XX(1616 to0
0) is shown in the
message every time the engine is started. When the number of
remaining engine starts is 0 0the engine management prevents the
vehicle being driven at a speed exceeding 5 mph (8 km/h). The
Idle Mode Idle Mode message appears in the multifunction display: The DEF reducing agent is contaminated, diluted or is not compli-
ant with ISO 22241.
X
Have the DEF tank cleaned and refilled at a qualified specialist
workshop as soon as possible. The exhaust gas aftertreatment is malfunctioning or an emission
relevant malfunction has occurred. This malfunction or defect can
damage the exhaust gas aftertreatment.
X
Visit a qualified specialist workshop immediately. Display
messages
203On-board computer and displays Z 

Display messages Possible causes/consequences and
0050
0050Solutions 0099
StArtS IdLE StArtS IdLE In addition, the yellow
00E2DEF indicator lamp lights up and a
warning tone sequence sounds.
The DEF supply has dropped below the 0.8 US gal (3.0 l) reserve
mark.
After the message appears for the first time, the remaining DEF
supply will last for approximately 1000 miles (1600 km). The
engine can then only be started another 16 times.
The number of remaining engine starts XX
XX (1616 to0 0) is shown in the
message every time the engine is started. If the number displayed
is 0 0, the yellow 00B9Check Engine indicator lamp also lights up
and you can only drive the vehicle at a maximum 5 mph
(8 km/h).
X Add at least 2.0 US gal (7.6 l) of DEF (Y page 149).
The 00E2 DEF indicator lamp disappears after no more than
20 seconds after the vehicle has stopped or you have switched
on the ignition or started the engine after refueling. Err Err flashes for 5 seconds, the
00CEindicator lamp also flashes and
then goes out.
Highbeam Assist is deactivated and temporarily not operational
or Highbeam Assist is malfunctioning.
Possible causes are:
R The camera's functionality is impaired due to heavy rain, snow
or fog.
R The windshield is dirty in the camera's field of vision.
X Stop the vehicle paying attention to road and traffic conditions.
X Secure the vehicle to prevent it from rolling away
(Y page 151).
X Clean the windshield (Y page 269), particularly in the camera's
field of vision.
If the 00CE indicator lamp goes out, Highbeam Assist is opera-
tional again.
If the problem persists, visit a qualified specialist workshop. 204
Display
messagesOn-board computer and displays 

Engine
Display messages Possible causes/consequences and
0050
0050Solutions Exhaust Filter:
Exhaust Filter:
Drive at high Drive at high
engine speed. See engine speed. See
Oper. Manual Oper. Manual The automatic regeneration of the diesel particle filter is not suf-
ficient or has malfunctioned.
X
Drive at an engine speed of above 2000 rpm until the display
message disappears.
If the display message does not go out after approximately
20 minutes, have the malfunction rectified immediately at a
qualified specialist workshop. Check Diesel Check Diesel
Exhaust Fluid See Exhaust Fluid See
Operator's Manual Operator's Manual The Diesel Exhaust Fluid (DEF) supply has dropped below
1.5 US gal (5.5 l).
After the message appears for the first time, and under normal
driving conditions, the remaining DEF supply will last for approx-
imately 1000 miles (1600 km).
After that, the 0.8 US gal (3.0 l) reserve mark is reached. A warning
tone sequence sounds and the engine can then only be started
another 16 times.
X Add DEF supply (Y page 149).
After topping up, the system check takes approximately
20 seconds. The display message then disappears. Check Diesel Check Diesel
Exhaust Fluid See Exhaust Fluid See
Operator's Manual Operator's Manual If the yellow
00B9Check Engine indicator lamp lights up as well,
the DEF reducing agent is contaminated, diluted or not compliant
with ISO 22241.
After the first message and under normal operating conditions,
you can drive on for up to approximately 50 miles (80 km). Then
a warning tone sequence sounds and the engine can only be
started another 16 times.
Have the DEF tank cleaned and refilled at a qualified specialist
workshop as soon as possible. Display messages
213On-board computer and displays Z