ECU MERCEDES-BENZ R-Class 2011 W251 Workshop Manual

Immediately rinse acid
splashes off with clean
water. Consult a doctor if
necessary.Wear eye protection.Keep children away.Observe this Operator's
Manual.HEnvironmental note
Do not dispose of batteries in the household
rubbish. Dispose of defective batteries in an
environmentally responsible manner. Take
them to an authorized Mercedes-Benz Center
or to a special collection point for old
batteries.
GWarning
Failure to follow these instructions can result
in severe injury or death.
Never lean over batteries while connecting.
You might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking etc.
GWarning
Do not place any metal objects on the battery
as this could result in a short circuit.
Use leak-proof batteries only to avoid the risk
of acid burns in the event of an accident.
Take care that you do not become statically
charged, e.g. by wearing synthetic clothing or
rubbing against textiles. For this reason, you
also should not pull or push the battery over
carpets or other synthetic materials.
Never touch the battery first. First, touch the
outside body of the vehicle in order to release
any possible electrostatic charges.
Do not rub the battery with rags or cloths. The
battery could explode if touched due to
electrostatic charge or due to spark
formation.
! Switch off the engine and remove the
SmartKey before disconnecting the
terminal clamps from the battery. On
vehicles with KEYLESS-GO, make sure that
the ignition is switched off. Check that all
the indicator lamps in the instrument
cluster are off. You may otherwise destroy
electronic components, such as the
alternator.
! Like other batteries, the vehicle battery
may discharge over time if you do not use
the vehicle. In this case, have the battery
disconnected at a qualified specialist
workshop, e.g. an authorized Mercedes-
Benz Center. You can also charge the
battery with a charger recommended by
Mercedes-Benz. Contact an authorized
Mercedes-Benz Center for further
information.
The battery, breather hose and cover of the
positive terminal clamp must be installed
securely during operation.
i Remove the SmartKey if you park the
vehicle and do not require any electrical
consumers. The vehicle will then use very
little energy, thus conserving battery
power.
Mercedes-Benz recommends that you do not
carry out work on batteries yourself, e.g.
removing, charging or replacing. Always have
this work performed at a qualified specialist
workshop, e.g. an authorized Mercedes-Benz
Center.Battery309Roadside AssistanceBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 309Z

Towing away
Important safety guidelines
GWarning
With the engine not running, there is no power
assistance for the brake and steering
systems. In this case, it is important to keep
in mind that a considerably higher degree of
effort is necessary to brake and steer the
vehicle. Adapt your driving accordingly.
If possible, have the vehicle transported by a
suitable vehicle with both axles raised,
instead of having it towed.
If it is not possible to load the vehicle due to
external conditions, tow the vehicle with both
axles on the ground the shortest distance
possible to a place where it is possible to load
the vehicle.
! When towing, pull away slowly and
smoothly. If the tractive power is too high,
the vehicles could be damaged.
! Do not use the towing eye for recovery,
as this could damage the vehicle. If in
doubt, recover the vehicle with a crane.
! You must not start the vehicle by tow-
starting. This could otherwise damage the
automatic transmission.
! Do not tow with sling-type equipment.
This could damage the vehicle.
! Only secure the tow rope or tow bar at the
towing eyes, or the trailer tow hitch, if
available. You could otherwise damage the
vehicle.
! When towing vehicles with KEYLESS-GO,
use the key instead of the Start/Stop
button. Otherwise, the automatic
transmission may shift to position P when
the driver's or front-passenger door are
opened, which could lead to damage to the
transmission.
! The vehicle must not be towed with raised
front or rear axles. This could otherwise
damage the transmission.
The battery must be connected and charged
when towing. Otherwise, you cannot switch
on the ignition and select N with the
automatic transmission.
i Switch the automatic door lock off before
towing ( Y page 208). Otherwise, you could
lock yourself out of the vehicle when
pushing or towing the vehicle.
Installing the towing eye
Vehicles with a trailer tow hitch: if possible,
fasten the towing mechanism to the trailer
tow hitch ( Y page 193).
XRemove the towing eye and the lug wrench
(if supplied) from the vehicle tool kit
( Y page 294).GWarning
In order to avoid possible serious burns or
injury, use extreme caution when removing
the rear cover, because the rear exhaust pipe
is extremely hot.
The mountings for the removable towing eyes
are located in the bumpers. They are at the
front and at the rear, behind the covers.
XPress the mark on cover : inwards, in the
direction of the arrow.Towing away313Roadside AssistanceBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 313Z

Recovering a vehicle that has become
stuck
Take great care when recovering a vehicle
whose drive wheels have become embedded
in loose earth or mud, particularly if the
vehicle is laden.
When recovering the vehicle, do not use jerky
movements and do not pull it at an angle. The
chassis could otherwise be damaged.
Never attempt to recover a vehicle with a
trailer attached.
Pull out the vehicle backwards, if possible
using the tracks it made when it became
stuck.
Transporting the vehicle
The towing eyes or trailer tow hitch can be
used to pull the vehicle onto a trailer or
transporter if you wish to transport it.
XTurn the SmartKey to position 2
( Y page 149) in the ignition lock.XShift the automatic transmission to
position N.
As soon as the vehicle has been loaded:
XPrevent the vehicle from rolling away by
applying the parking brake.XShift the automatic transmission to
position P.XSwitch off the ignition.XSecure the vehicle.
!
Only lash the vehicle down by the wheels
or wheel rims, not by parts of the vehicle
such as axle or steering components.
Otherwise, the vehicle could be damaged.
Fuses
Important safety guidelines
The fuses in your vehicle serve to close down
faulty circuits. If a fuse blows, all the
components on the circuit and their functions
will fail.GWarning
Only use fuses approved by Mercedes-Benz
with the specified amperage for the system in
question and do not attempt to repair or
bridge a blown fuse. Using other than
approved fuses or using repaired or bridged
fuses may cause an overload leading to a fire,
and/or cause damage to electrical
components and/or systems. Have the cause
determined and remedied by an authorized
Mercedes-Benz Center.
Blown fuses must be replaced with fuses of
the same rating, which you can recognize by
the color and value. The fuse ratings are listed
in the fuse allocation chart. An authorized
Mercedes-Benz Center will be happy to
advise you.
i If a fuse has blown, visit a breakdown
service or an authorized Mercedes-Benz
Center.
If the newly inserted fuse also blows, have the
cause traced and rectified at a qualified
specialist workshop, e.g. an authorized
Mercedes-Benz Center.
! Only use fuses that have been approved
for Mercedes-Benz vehicles and which
have the correct fuse rating for the system
concerned. Otherwise, components or
systems could be damaged.
Before changing a fuse
XPark the vehicle and apply the parking
brake.XSwitch off all electrical consumers.XRemove the key from the ignition lock.Fuses315Roadside AssistanceBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 315Z

The fuses are located in various fuse boxes:
R fuse box on the front-passenger side of the
dashboard
R fuse box in the engine compartment on the
right-hand side of the vehicle, when viewed
in the direction of travel
R fuse box in the stowage well under the
trunk floor
The fuse allocation chart is located in the
vehicle tool kit ( Y page 294) in the stowage
compartment under the trunk floor.
Fuse box in the cockpit
! Do not use a pointed object such as a
screwdriver to open the cover in the
dashboard. You could damage the
dashboard or the cover.
XTo open: pull cover : upwards in the
direction of the arrow and remove it.XTo close: clip in cover : on top of the
dashboard.XFold cover : inwards until it engages.
Fuse box in the engine compartment
XOpen the hood ( Y page 278).XRemove any existing moisture from the
fuse box using a dry cloth.XTo open: open clamp :.XFold up cover ; and remove it.XTo close: check whether the rubber seal is
lying correctly in cover ;.XInsert cover ; at the front of the fuse box
into the retainer.XFold down cover ; and close clamp :.
!
The cover must be seated properly,
otherwise moisture or dirt could impair the
function of the fuses.
XClose the hood ( Y page 279).
Fuse box in the cargo compartment
XOpen the tailgate.XTo open: open the trunk floor and secure
it ( Y page 294).XFold cover : to the left in the direction of
the arrow.316FusesRoadside Assistance
BA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 316

Underinflated tires can:
R wear excessively and/or unevenly
R adversely affect fuel economy
R fail from being overheated
R adversely affect handling
Overinflated tires can:GWarning
Follow recommended tire inflation pressures.
Do not overinflate tires. Overinflated tires can
adversely affect handling and ride comfort,
wear unevenly, increase stopping distance,
and result in sudden deflation (blowout)
because they are more likely to become
punctured or damaged by road debris,
potholes etc.
Overinflated tires can:
R adversely affect handling
R wear excessively and/or unevenly
R be more likely to become damaged
R adversely affect ride comfort
R increase stopping distance
Checking tire pressures
Important safety guidelines
GWarning
Follow recommended tire inflation pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly, adversely
affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires can
adversely affect handling and ride comfort,
wear unevenly, increase stopping distance,
and result in sudden deflation (blowout)
because they are more likely to become
punctured or damaged by road debris,
potholes etc.
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard on the
driver's door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout. Overloading the tires can also result
in handling or steering problems, or brake
failure.
Check the tire pressure at least once a month.
Only check and correct tire pressures when
the tires are cold ( Y page 322).
Checking the tire pressures manually
In order to determine and adjust the tire
pressures, proceed as follows:
XRemove the valve cap of the tire you wish
to check.XPress the tire pressure gauge securely onto
the valve.XRead the tire pressure and compare it with
the recommended value on the Tire and
Loading Information placard on the
B-pillar on the driver's side of your vehicle.XIf necessary, increase the tire pressure to
the recommended value ( Y page 322).XIf the tire pressure is too high, release air
by pressing down the metal pin in the valve
using the tip of a pen, for example. Then,
check the tire pressure again using the tire
pressure gauge.XScrew the valve cap onto the valve.XRepeat the steps for the other tires.
Tire pressure loss warning system
(Canada only)
Important safety guidelines
While the vehicle is in motion, the tire
pressure loss warning system monitors the
set tire pressure using the rotational speed of
the wheels. This enables the system to detect
significant pressure loss in a tire. If the speed
of rotation of a wheel changes as a result of
a loss of pressure, a corresponding warning
Tire pressures325Tires and wheelsBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 325Z