2012 MERCEDES-BENZ E-CLASS CABRIOLET check engine

or winding roads). You may otherwise
cause an accident.
R on slippery roads. The drive wheels may
lose their grip when braking or accelerating
and the vehicle may skid.
R when there is low visibility, e.g. due to fog,
heavy rain or snow.
General notes Cruise control maintains a constant road
speed for you. It brakes automatically in order
to avoid exceeding the set speed. You must
select a low gear in good time on long and
steep downhill gradients, especially if the
vehicle is laden or towing a trailer. On vehicles
with automatic transmission, select shift
range 1,2or 3.B y doing so, you will make
use of the braking effec tofthe engine. This
relieves the load on the brake system and
prevents the brakes from overheating and
wearing too quickly.
Use cruise control only if road and traffic con-
ditions make it appropriate to maintain a
steady speed for a prolonged period. You can
store any road speed above 30 km/h.
Cruise control lever :
To activate or increase speed
; LIM indicator lamp
= To activate at the current speed/last
stored speed
? To activate or reduce speed A
To switch between cruise control and var-
iable SPEEDTRONIC
B To deactivate cruise control
You can operate cruise control and variable
SPEEDTRONIC with the cruise control lever.
The LIM indicator lamp on the cruise control
lever indicates which system you have selec-
ted:
R LIM indicator lamp off: cruise control is
selected.
R LIM indicator lamp on: variable SPEED-
TRONIC is selected.
When you activate cruise control, the stored
speed is shown in the multifunction display
for five seconds. In the multifunction display,
the segments between the stored speed and
the maximum speed light up.
Activation conditions To activate cruise control, all of the following
activation conditions must be fulfilled:
R
the parking brake must be released.
R you must be driving faster than 30 km/h.
R ESP ®
must be switched on, but not inter-
vening.
R the transmission must be in position D.
R the cruise control function must be selec-
ted (Y page 183).
Selecting cruise control X
Check whether LIM indicator lamp :is off.
If it is off, cruise control is already selected. Driving systems
183Driving and parking Z

:
Yellow indicator lamp/red warning lamp
If Blind Spot Assist is switched on, indicator
lamp :in the exterior mirrors lights up yel-
low up to a speed of 30 km/h. At speeds
above 30 km/h, the indicator lamp goes out
and Blind Spot Assist is operational.
If a vehicle is detected within the monitoring
range of Blind Spot Assist at speeds above
30 km/h, warning lamp :on the corre-
sponding side lights up red. This warning
always occurs when a vehicle enters the blind
spot monitoring rang efrom behind or from
the side .When you overtake a vehicle, the
warning only occurs if the difference in speed
is less than 12 km/h.
The yellow indicator lamp goes out if reverse
gear is engaged. Blind Spot Assist is then
deactivated.
The brightness of the indicator/warning
lamps is adjusted automatically according to
the ambient light.
Collision warning
If a vehicle is detected in the monitoring range
of Blind Spot Assist and you switch on the
corresponding turn signal, a double warning
tone sounds. Red warning lamp :flashes. If
the turn signal remains on, detected vehicles
are indicated by the flashing of red warning
lamp :.There are no further warning tones.
Switching on Blind Spot Assist
X Make sure that the radar sensor system
(Y page 245) and Blind Spot Assist (Y
page 241) are activated in the on-board
computer.
X Turn the key to position 2in the ignition
lock.
Warning lamps :in the exterior mirrors
light up red for approximately
1.5 seconds and then turn yellow.
Towing atrailer
If you attach a trailer, make sure tha tyou have
correctly established the electrical connec-
tion. This can be accomplished by checking
the trailer lighting. Blind Spot Assist is then
deactivated. The indicator lamp lights up yel-
low in the exterior mirrors and the message:
Blind Spot Assist currently unavail‐
able See Owner's Manual appears in the
multifunction display.
i You can deactivate the indicator lamps in
the exterior mirrors.
To do so, switch off Blind Spot Assist if:
R the key is in position 2in the ignition
lock.
R the engine is not running.
R the electrical connection to the trailer
has been established.
Lane Keeping Assist Important safety notes
G
WARNING
Lane Keeping Assist does not keep your vehi-
cle in its lane. It is only an aid and may detect
the lane markings on the road incorrectly or
not at all.
The system may be impaired or may not func-
tion if:
R there is poor visibility, e.g. due to insuffi-
cient illumination of the road, or due to
snow, rain, fog or spray.
R there is glare, e.g. from oncoming traffic,
the sun, or reflection from other vehicles. 212
Driving systemsDriving and parking

X
Press the abutton.
The multifunction display shows Speed
Limit Assist.
X Press the :button.
The curren tselection is displayed.
X To activate or deactivate: pressa.
If the Speed Limit Assist message function
is activated, a detected speed limit is auto-
matically displayed for five seconds. Other
items in the multifunction display are not
shown during this time.
If Speed Limit Assist is operational and the
message function is activated, the multifunc-
tion display shows the Äsymbol when the
ignition is switched on.
Showing the distance display X
Press the =or; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9or: button to select
Distance display .
X Press the abutton.
The DISTRONIC PLUS distance display
appears in the multifunction display
(Y page 195).
If the Sensors deactivated message
appears, the radar sensor system is deacti-
vated.
X Check whether or not the radar sensor sys-
tem is permitted to be activated
(Y page 382).
X Switch on the radar sensor system
(Y page 245).
Deactivating/activating ESP ®G
WARNING
If you deactivate ESP ®
, ESP ®
no longer sta-
bilises the vehicle. There is an increased risk
of skidding and an accident.
Only deactivate ESP ®
in the situations descri-
bed in the following. For further information about ESP
®
, see
(Y page 67).
X Start the engine.
X Press the =or; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9or: button to select
ESP .
X Press the abutton.
The curren tselection is displayed.
X To activate/deactivate: press thea
button again.
ESP ®
is deactivated if the åwarning lamp
in the instrument cluster lights up continu-
ously when the engine is running.
If the ä warning lamp and the åwarn-
ing lamp are lit continuously, ESP ®
is not
available due to a malfunction.
It may be best to deactivate ESP ®
in the fol-
lowing situations:
R when using snow chains
R in deep snow
R on sand or gravel
Observe the information on warning lamps
(Y page 278).
Observe the information on display messages
(Y page 250).
Activating/deactivating the PRE-SAFE ®
Brake PRE-SAFE
®
Brake is only available in vehicles
with DISTRONIC PLUS.
X Press the =or; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9or: button to select
PRE-SAFE Brake .
X Press the abutton.
The curren tselection is displayed.
X To activate/deactivate: press thea
button again.
When PRE-SAFE ®
Brake is activated, the mul-
tifunction display shows the Äsymbol as 240
Menus and submenusOn-board computer and displays

Display messages Possible causes/consequences and
M Solutions
J
Check brake fluid
level There is insufficien
tbrake fluid in the brake flui dreservoir.
In addition, the red Jwarning lamp lights up in the instrument
cluster and a warning tone sounds.
G WARNING
The 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 .Donot continue driving
under any circumstances.
X Secure the vehicle against rolling away (Y page 177).
X Consult a qualified specialist workshop.
X Do not top up the brake fluid. This does not correct the error. #
Check brake pad
wear The brake pads/linings have reached their wear limit.
X Visit a qualified specialist workshop. PRE-SAFE
inoperative See
Owner's Manual Important functions of PRE-SAFE
®
have failed. All other occupant
safety systems, e.g. airbags, remain available.
X Visit a qualified specialist workshop immediately. PRE-SAFE
Functions cur‐
rently limited See
Owner's Manual PRE-SAFE
®
Brake 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.
Once the causes listed above no longer apply, the display message
goes out.
PRE-SAFE ®
Brake 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 against rolling away (Y page 177).
X Clean the sensors in the radiator trim and in the bumpers
(Y page 317).
X Restart the engine. Display messages
253On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
b
Switch off lights The lights are still switched on when you leave the vehicle. A
warning tone also sounds.
X Tur nthe light switch to Ã. Adaptive Main-beam
Assist inoperative Adaptive Highbeam Assist is faulty.
X
Visit a qualified specialist workshop. Adaptive Main-beam
Assist currently
unavailable See
Owner's Manual Adaptive Highbeam Assist is deactivated and temporarily inoper-
ative. 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.
X Cleant he windscreen.
If the system detects that the camera is fully operational again,
the Adaptive Main-beam Assist available again message
is displayed.
Adaptive Highbeam Assist is operational again. Engine
Display messages Possible causes/consequences and
M Solutions
+
Top
up coolant See
Owner's Manual The coolant level is too low.
!
Avoid making long journeys with too little coolant in the engine
cooling system. The engine will otherwise be damaged.
X Top up the coolant, observing the warning notes before doing
so (Y page 310).
X If the coolant needs topping up more often than usual, have the
engine coolant system checked at a qualified specialist work-
shop. ? The fan motor is faulty.
X
If the coolant temperature is below 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving in
mountainous terrain and stop-start traffic. Display messages
259On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
# The battery is no
tbeing charged.
Aw arning tone also sounds.
Possible causes:
R faulty alternator
R torn poly-V-belt
R a malfunction in the electronics
X Stop the vehicle immediately, paying attentio ntoroad and traf-
fic conditions, and switch off the engine.
X Secure the vehicle against rolling away (Y page 177).
X Open the bonnet.
X Check whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not continue driving. The engine could otherwise overheat.
X Consult a qualified specialist workshop.
If the poly-V-belt is OK:
X Visit a qualified specialist workshop. 4
Check eng. oil
lev. when next
refuelling The engine oil level has dropped to the minimum level.
Aw
arning tone also sounds.
X Chec kthe oil level when next refuelling, at the latest
(Y page 309).
X If necessary, top up the engine oil (Y page 309).
X Have the engine checked at a qualified specialist workshop if
the engine oil needs topping up more often than usual. 8
Reserve fuel level The fuel level has dropped into the reserve range.
Operation of the auxiliary heating is deactivated when the fuel level
drops into the reserve range.
X
Refuel at the nearest filling station. C There is only a very small amount of fuel in the fuel tank.
The auxiliary heating cannot be operated.
X
Refuel at the nearest filling station without fail. Display messages
261On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
DISTRONIC PLUS cur‐
rently unavailable
See Owner's Manual DISTRONIC PLU
Sis 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.
Aw arning tone also sounds.
Once the causes listed abov eno 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 against rolling away (Y page 177).
X Clean the sensors in the radiator trim and in the bumpers
(Y page 317).
X Restart the engine. 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
inactive 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 188). DISTRONIC PLUS and
SPEEDTRONIC DISTRONIC PLUS and SPEEDTRONIC are faulty. A warning tone
also sounds.
X Visit a qualified specialist workshop. Cruise control and
SPEEDTRONIC inop‐
erative SPEEDTRONIC and cruise control are malfunctioning.
Aw arning tone also sounds.
X Visi taqualified specialist workshop. Display messages
267On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions
j
Check trailer
hitch lock The trailer tow hitch is no
tcorrectly engaged.
Aw arning tone also sounds.
X Stop the vehicle immediately, paying attentio ntoroad and traf-
fic conditions, and switch off the engine.
X Apply the parking brake.
X Allow the trailer tow hitch ball coupling to engage in the end
position (Y page 222). &
inoperative Bat‐
tery low The on-board voltage is too low. The auxiliary heating has switched
itself off or cannot be switched on (Y
page 149).
X Drive for a longer distance.
The battery is being charged. The auxiliary heating is operational
again as soon as the on-board electrical system voltage is suf-
ficient. &
inoperative
Refuel
vehicle There is too little fuel in the fuel tank.T
he auxiliary heating cannot
be switched on (Y page 149).
X Refuel at the nearest filling station. &
inoperative See
Owner's Man. The auxiliary heating has a temporary malfunction or is faulty.
X
When the vehicle is on alevel 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 149).
X If the auxiliary heating does not switch on, consult a qualified
specialist workshop. J
Close boot separa‐
tor Cabriolet: the boot separator is open.
X
Close the boot separator (Y page 99).Ð
Power
steering mal‐
function See Own‐
er's Manual The power steering assistance is faulty.
Aw
arning tone also sounds.
G WARNING
You will need to use more force to steer.
There is a ris kofaccident.
X Check whethe ryou are able to apply the extra force required.
X If you are able to steer safely: carefully drive on to a qualified
specialist workshop.
X If you are unable to steer safely: do not drive on. Contact the
nearest qualified specialist workshop. 272
Display messagesOn-board computer and displays