ECU MERCEDES-BENZ S-CLASS SEDAN 2012 Owner's Guide

residues crystallize after time and
contaminate the affected surfaces.
! DEF is not a fuel additive and must not be
added to the fuel tank. If DEF is added to
the fuel tank, this can lead to engine
damage.
! Only screw on the DEF refill bottle hand-
tight. It could otherwise be damaged.
The filler neck for DEF is located under the
"Minispare" emergency spare wheel in the
trunk floor.XSwitch off the ignition.XOpen the trunk.XLift the trunk floor up ( Y page 438).XTurn the "Minispare" emergency spare
wheel fastening in the direction of the
arrow and remove it.XRemove the "Minispare" emergency spare
wheel.XTurn DEF cap : counter-clockwise and
remove it.XTurn DEF filler cap ; counter-clockwise
and open it.
Filler cap ; is secured with a plastic strap.XUnscrew the covering cap from DEF refill
bottle =.XPlace DEF refill bottle = on the filler neck
as shown and screw on clockwise hand-
tight.XPress DEF refill bottle = down.
The DEF tank is filled. This may take up to
one minute.
i To add between service intervals, fill the
DEF tank with approximately 1 gal (3.8 l) of
DEF. 1 gal (3.8 l) of DEF is equivalent to
approximately 2 DEF refill bottles. Then
have the DEF supply checked at a qualified
specialist workshop and completely refilled
if necessary.
XRelease DEF refill bottle =.
Refilling stops when the DEF refill bottle is
no longer pressed down. The DEF refill
bottle can be removed when it has been
only partially emptied.326RefuelingDriving and parking

up : or down ; beyond the pressure
point.
The last speed stored is increased or
decreased every time the cruise control
lever is pushed up : or down ;.
i
Cruise control is not deactivated if you
depress the accelerator pedal. For
example, if you accelerate briefly to
overtake, cruise control adjusts the
vehicle's speed to the last speed stored
after you have finished overtaking.
Deactivating cruise control
There are several ways to deactivate cruise
control:
XBriefly press the cruise control lever
forwards =.
or
XBrake.
Cruise control is automatically deactivated if:
R you engage the electric parking brake.
R you are driving at less than 20 mph
(30 km/h)
R ESP ®
intervenes or you deactivate ESP ®
.
R you shift the transmission to position N
while driving.
If cruise control is deactivated, you will hear
a warning tone. You will see the Cruise
Control Off message in the multifunction
display for approximately five seconds.
i When you switch off the engine, the last
speed stored is cleared.
DISTRONIC PLUS
Important safety notes
DISTRONIC PLUS regulates the speed and
automatically helps you maintain the
distance to the vehicle detected in front.
DISTRONIC PLUS brakes automatically so
that the set speed is not exceeded.
On long and steep downhill gradients,
especially if the vehicle is laden, you must
select shift range 1, 2 or 3 in good time. By
doing so, you will make use of the braking
effect of the engine, which relieves the load
on the brake system and prevents the brakes
from overheating and wearing too quickly.
If DISTRONIC PLUS detects a slower-moving
vehicle in front, your vehicle is braked in order
to maintain the preset distance to the vehicle
in front.GWARNING
HYBRID vehicles: It is imperative that you read
the HYBRID Supplemental Operating
Instructions included in your vehicle literature
portfolio. You may otherwise not receive all
necessary safety information and warning for
the operation of your vehicle.
GWARNING
The DISTRONIC PLUS requires familiarity with
its operational characteristics. We strongly
recommend that you review the following
information carefully before operating the
system.
GWARNING
When DISTRONIC brakes, the brake pedal is
pulled back (i.e. operated automatically). The
area around the pedal must not be blocked by
obstacles:
R do not place any objects in the footwell.
R ensure that floormats and carpets are fixed
securely. In particular, do not place several
floormats on top of one another.
R do not place your foot under the brake
pedal, as it could become trapped.
Non-compliance could lead you to cause an
accident in which you and/or others could be
seriously injured.
GWARNING
The DISTRONIC PLUS is a convenience
system. Its speed adjustment reduction
capability is intended to make cruise control
336Driving systemsDriving and parking

If these conditions are fulfilled, your vehicle
is accelerated. Acceleration will be
interrupted if changing lanes takes too long
or if the distance between your vehicle and
the vehicle in front becomes too small.
i When changing lanes, DISTRONIC PLUS
monitors the left lane on left-hand drive
vehicles and the right lane on right-hand
drive vehicles.GWARNING
DISTRONIC PLUS and Active Blind Spot Assist
are only aids designed to assist driving.
They do not relieve you of the responsibility
of paying attention. The driver remains fully
responsible for the vehicle's distance from
other vehicles, the vehicle's speed and for
braking in good time. Always pay attention to
traffic conditions and your surroundings.
Otherwise, you may fail to recognize dangers
in time, cause an accident and injure yourself
and others.
Stopping
GWARNING
Never get out of the vehicle when DISTRONIC
PLUS is activated.
DISTRONIC PLUS must also never be
operated, activated or deactivated by a
passenger or from outside the vehicle.
DISTRONIC PLUS does not replace the
electric parking brake and must not be used
for parking.
The DISTRONIC PLUS braking effect is
canceled and the vehicle can start moving if:
R DISTRONIC PLUS is deactivated using the
cruise control lever.
R you accelerate.
R there is a malfunction in the system or an
interruption in the power supply, e.g.
battery failure.
R the electrical system in the engine
compartment, the battery or the fuses are
tampered with.
R the battery is disconnected.
If you wish to leave the vehicle or park it,
deactivate DISTRONIC PLUS and secure the
vehicle against rolling away.
If DISTRONIC PLUS detects that the vehicle
in front is stopping, it brakes your vehicle until
it is stationary.
Once your vehicle is stationary, it remains
stationary and you do not need to depress the
brake.
i After a time, the electric parking brake
secures the vehicle and relieves the service
brake.
i Depending on the specified minimum
distance, your vehicle will come to a
standstill at a sufficient distance behind the
vehicle in front. The specified minimum
distance is set using the control on the
cruise control lever.
Setting a speedGWARNING
Keep in mind that it may take a brief moment
until the vehicle has made the necessary
adjustments.
Increase or decrease the set vehicle speed to
a value that the prevailing road conditions and
legal speed limits permit. Otherwise, sudden
and unexpected acceleration or deceleration
of the vehicle could cause an accident and/
or serious injury to you and others.
XPress the cruise control lever up : for a
higher speed or down ; for a lower speed.XTo adjust the speed in 1 mph
increments (1 km/h increments): briefly
press the cruise control lever up : or
down ; to the pressure point.
The last speed stored is increased or
decreased every time the cruise control
lever is pushed up : or down ;.XTo adjust the speed in 5 mph
increments (10 km/h increments):
briefly press the cruise control leverDriving systems341Driving and parkingZ

When you deactivate DISTRONIC PLUS, the
DISTRONIC PLUS Off message is shown in
the multifunction display for approximately
five seconds.
i The last speed stored remains stored until
you switch off the engine.
DISTRONIC PLUS is automatically
deactivated if:
R you engage the electric parking brake or if
the vehicle is automatically secured with
the electric parking brake
R you are driving slower than 15 mph
(25km/h) and there is no vehicle in front,
or if the vehicle in front is no longer
detected.
R ESP ®
intervenes or you deactivate ESP ®
.
R the transmission is in the P, R or N position.
R you switch off the radar sensor system
( Y page 389).
R you pull the cruise control lever towards
you in order to pull away and the front-
passenger door or one of the rear doors is
open.
R the vehicle has skidded.
If DISTRONIC PLUS is deactivated, you will
hear a warning tone. The DISTRONIC PLUS
Off message is shown in the multifunction
display for approximately five seconds.GWARNING
DISTRONIC PLUS is deactivated and releases
the brakes if the vehicle is slowed down to a
speed below 20 mph ( 30km/h) by the system,
provided that DISTRONIC PLUS does not
detect a vehicle directly in front. At this point,
the driver must apply the brakes in order to
slow down further and bring the vehicle to a
standstill.
Tips for driving with DISTRONIC PLUS
Important safety notes
The following contains descriptions of certain
road and traffic conditions in which you must
be particularly attentive. In such situations,
brake if necessary. DISTRONIC PLUS is then
deactivated.GWARNING
The DISTRONIC PLUS works to maintain the
speed selected by the driver unless a moving
obstacle proceeding directly ahead of it in the
same travel direction is detected (e.g.
following another vehicle ahead of you at your
set distance).
This means that:
R Your vehicle can pass another vehicle after
you have changed lanes.
R While in a sharp turn or if the preceding
vehicle is in a sharp turn, the DISTRONIC
PLUS could lose sight of the preceding
vehicle. Your vehicle could then accelerate
to the previously selected speed.
The DISTRONIC PLUS regulates only the
distance between your vehicle and those
directly ahead of it. It may not register
stationary objects in the road, e.g.:
R a stopped vehicle in a traffic jam
R a disabled vehicle
R an oncoming vehicle
The driver must always be alert, observe all
traffic and intercede as required by means of
steering or braking the vehicle.
GWARNING
The DISTRONIC PLUS should not be used in
snowy or icy road conditions.
Cornering, going into and coming out of a
bend
344Driving systemsDriving and parking

HOLD function
General notes
The HOLD function can assist the driver in the
following situations:
R when pulling away, especially on steep
slopes
R when maneuvering on steep slopes
R when waiting in traffic
The vehicle is kept stationary without the
driver having to depress the brake pedal.
The braking effect is canceled and the HOLD
function deactivated when you depress the
accelerator pedal to pull away.
GWARNING
HYBRID vehicles: It is imperative that you read
the HYBRID Supplemental Operating
Instructions included in your vehicle literature
portfolio. You may otherwise not receive all
necessary safety information and warning for
the operation of your vehicle.
Activation conditions
You can activate the HOLD function if:
R the vehicle is stationary.
R the driver's door is closed or your seat belt
is fastened.
R the electric parking brake is released.
R the hood is closed.
R the transmission is in position R, N or D.
The trunk lid must be closed in position R.
R DISTRONIC PLUS is deactivated.
Activating the HOLD function
XMake sure that the activation conditions
are met.XDepress the brake pedal.XQuickly depress the brake pedal further
until ë appears in the instrument
cluster.
The HOLD function is activated. You can
release the brake pedal.i If depressing the brake pedal the first
time does not activate the HOLD function,
wait briefly and then try again.GWARNING
The vehicle's brakes are applied when the
HOLD function is activated. For this reason,
deactivate the HOLD function if the vehicle is
to be set in motion by other means (e.g. in a
car wash or by towing).
Deactivating the HOLD function
The HOLD function is deactivated
automatically if:
R you accelerate and the transmission is in
position D or R.
R you shift the transmission to position P.
R you apply the brakes again with a certain
amount of pressure until ë disappears
from the instrument cluster.
R you secure the vehicle using the electric
parking brake.
R you activate DISTRONIC PLUS.
i After a time, the electric parking brake
secures the vehicle and relieves the service
brake.
GWARNING
Never get out of the vehicle when the HOLD
function is activated.
The HOLD function must never be operated
or deactivated by a passenger or from outside
the vehicle.
The HOLD function does not replace the
electric parking brake and must not be used
for parking.
The braking effect of the HOLD function is
canceled and the vehicle could roll away if:
R the HOLD function is deactivated by
depressing the accelerator pedal or the
brake pedal.
R there is a malfunction in the system or an
interruption in the power supply, e.g.
battery failure.
346Driving systemsDriving and parking

Rthe electrical system in the engine
compartment, the battery or the fuses are
tampered with.
R the battery is disconnected.
If you leave the vehicle or park it, deactivate
the HOLD function and secure the vehicle
against rolling away.
AIRMATIC
Vehicle level
Important safety notes
Your vehicle regulates its height
automatically. All-round level control ensures
the best possible suspension and constant
ground clearance, even with a laden vehicle.
When you drive fast, the vehicle is lowered
automatically to improve driving safety and to
reduce fuel consumption.
The following vehicle levels are possible on
vehicles without 4MATIC:
R Normal
R raised: the vehicle is raised by about 1 in
(25 mm) when compared with the normal
level
R lowered: the vehicle is lowered by about
0.60 in (15 mm) when compared with the
normal level
The following vehicle levels are possible on
vehicles with 4MATIC:
R normal: in Comfort mode, the vehicle is
raised by about 0.40 in (10 mm) when
compared with Sport mode
R raised: in Comfort mode, the vehicle is
raised by about 0.60 in (15 mm) and in
Sport mode by about 1 in (25 mm) when
compared with normal level
R lowered: the vehicle is lowered by about
0.40 in (10mm) when compared with the
normal level
The "Normal" and "Raised" vehicle levels can
be set manually.
The "Lowered” vehicle level is set
automatically:
R in vehicles without 4MATIC at speeds
above 60 mph (100 km/h)
R in vehicles with 4MATIC at speeds above
50 mph (80 km/h).
Setting the vehicle level
Select the "Normal" setting for normal road
surfaces and "Raised" for driving with snow
chains or on particularly poor road surfaces.
Your selection remains stored even if you
remove the SmartKey from the ignition lock.GWARNING
To help avoid personal injury, keep hands and
feet away from wheel housing area, and stay
away from under the vehicle when lowering
the vehicle chassis.
Setting raised level
XStart the engine.
If indicator lamp ; is not lit:
XPress button :.
Indicator lamp ; lights up. The vehicle
height is adjusted to raised level.
The Vehicle Rising message appears in
the display.
The "Raised level" setting is canceled if you:
R drive at speeds above 75 mph (120 km/h)
R drive for about three minutes at speeds
above 50 mph (80 km/h).
The "Raised level" remains active when you
are not driving within these speed ranges.
Driving systems347Driving and parkingZ

Display messagesPossible causes/consequences and M SolutionsThe red F (USA only)/ ! (Canada only) indicator lamp
flashes, the yellow F (USA only)/ ! (Canada only) warning
lamp lights up and a warning tone sounds.
The electric parking brake is malfunctioning and the braking effect
is restricted.
While the vehicle is in motion:XRelease the electric parking brake handle.
While the vehicle is stationary:
XSwitch off the ignition and turn it back on.XRelease the electric parking brake.
If the display message continues to be displayed:
XShift the transmission to P.XUse the folding wheel chock (Y page 476) from the vehicle tool
kit to secure the vehicle against rolling away.XConsult a qualified specialist workshop.F (USA only)
! (Canada only)
Parking Brake See
Oper. ManualThe yellow F (USA only)/ ! (Canada only) warning lamp
lights up. Additionally, the red F (USA only)/ ! (Canada
only) indicator lamp may light up.
The electric parking brake is malfunctioning.
To release:XPull the electric parking brake handle.
or
XPull away carefully.XVisit a qualified specialist workshop.
To apply:
XSwitch the ignition off.XPull the electric parking brake lever for at least ten seconds,
until the display message disappears.
If the display message continues to be displayed:
XShift the transmission to P.XUse the folding wheel chock (Y page 476) from the vehicle tool
kit to secure the vehicle against rolling away.XConsult a qualified specialist workshop.Display messages395On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsThe yellow F (USA only)/ ! (Canada only) warning lamp
lights up. The red F (USA only)/ ! (Canada only) indicator
lamp flashes for approximately ten seconds after the electric
parking brake has been applied or released. It then goes out or
remains lit.
The electric parking brake has overheated.XAllow the vehicle to cool down. Do not engage or release the
electric parking brake during this time.XUse the folding wheel chock (Y page 476) from the vehicle tool
kit to secure the vehicle against rolling away.XWhen the vehicle has cooled down: switch the ignition off and
on again, then engage or release the electric parking brake.F (USA only)
! (Canada only)
Parking Brake
InoperativeThe yellow F (USA only)/ ! (Canada only) warning lamp
lights up. The red F (USA only)/ ! (Canada only) indicator
lamp flashes for approximately 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.XSwitch the ignition off and on, and then engage the electric
parking brake.
If it is not possible to engage the electric parking brake:
XShift the transmission to P.XUse the folding wheel chock (Y page 476) from the vehicle tool
kit to secure the vehicle against rolling away.XConsult a qualified specialist workshop.F (USA only)
! (Canada only)
Turn On the
Ignition to
Release the
Parking BrakeThe red F (USA only)/ ! (Canada only) indicator lamp lights
up.
You attempted to release the electric parking brake while the
ignition was switched off.XSmartKey: turn the SmartKey to position 1 in the ignition lock.XKEYLESS-GO: switch on the ignition.Display messages397On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsFront Passenger
Airbag Enabled
See Oper. ManualThe front-passenger air bag is enabled during the journey, even
though:
R a child, a small adult or an object weighing less than the
system's weight threshold is located on the front-passenger
seat.
R the front-passenger seat is unoccupied.
The system may detect objects or forces applying additional
weight on the seat.XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XApply the parking brake.XSwitch the ignition off.XOpen the front-passenger door.XRemove the child and the child restraint system from the front-
passenger seat.XIf necessary, secure the child in a child restraint system on a
suitable rear seat.XMake sure that there are no objects on the seat adding to the
weight.
The system may otherwise detect the additional weight and
interpret the seat occupant's weight as greater than it actually
is.XKeep the seat unoccupied, close the front-passenger door and
switch on the ignition.
Observe the 42 (Y page 54) indicator lamp and the
multifunction display and check the following:
Seat unoccupied and ignition switched on:
R the 42 indicator lamp must light up and remain lit.
When the indicator lamp is on, OCS (Y page 54) has deactivated
the front-passenger air bag.
R the Front Passenger Airbag Enabled See Oper. Manual
or Front Passenger Airbag Disabled See Oper. Manual
display messages must not appear in the multifunction display.
Wait for a period of at least 60 seconds until the necessary
system checks have been completed and to make sure that the
display messages do not appear in the multifunction display.
If the conditions are not fulfilled, the system is not operating
correctly.
XVisit a qualified specialist workshop immediately.Display messages401On-board computer and displaysZ

ProblemPossible causes/consequences and M Solutions7
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.GRisk of injury
The driver or front passenger has not fastened their seat belt.
XFasten your seat belt ( Y page 61).
The warning lamp goes out.GRisk of injury
There are objects on the front-passenger seat.
XRemove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out.7
The red seat belt
warning lamp flashes
and an intermittent
audible warning
sounds.GRisk of injury
The driver or front passenger has not fastened their seat belt. In
addition, you are driving faster than 15 mph (25 km/h) or you have
briefly driven faster than 15 mph (25 km/h).
XFasten your seat belt ( Y page 61).
The warning lamp goes out and the intermittent warning tone
ceases.GRisk of injury
There are objects on the front-passenger seat. In addition, you are
driving faster than 15 mph (25 km/h) or you have briefly driven
faster than 15 mph (25 km/h).
XRemove 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 cluster423On-board computer and displaysZ