ESP MERCEDES-BENZ R-Class 2012 W251 Repair Manual

XStart the engine.XClose all doors and the tailgate.XApply the trailer's parking brake.GWARNING
Vehicles with AIRMATIC: As soon as you
disconnect the electrical connection between
the trailer and the vehicle, the vehicle will
lower. To help avoid personal injury, make
sure no one is near the wheel housing or
underneath the vehicle before the electrical
connection is disconnected.
When you decouple the trailer, the vehicle is
temporarily raised because the springs are
relieved of load. Be especially careful during
this process, as you could otherwise injure
yourself and/or others. Make sure that any
persons remaining in the vehicle do not press
the switches for vehicle level control or the
ADS.
XRemove the trailer cable and decouple the
trailer.XSwitch off the engine.
Permissible trailer loads and drawbar
noseweights
Weight specifications
The Gross Trailer Weight (GTW) is the
combined weight of the trailer together with
the cargo and equipment loaded on the
trailer. Permissible gross weight: 3500 lb
(1588 kg).
The permissible Trailer drawbar Weight
Rating (TWR) is the maximum weight
permitted on the trailer drawbar: 350 lb
(158 kg) limit for Mercedes-Benz-approved
trailer couplings.
Loading a trailer
R When loading a trailer, please note that
neither the permissible gross trailer weight
nor the permissible Gross Vehicle Weight
Rating (GVWR) may be exceeded. The
permissible Gross Vehicle Weight Rating
(GVWR) is specified on the type plate
located on the B-pillar on the driver's side
of your vehicle.
You can find the maximum permissible
values on the type plates of your vehicle
and the trailer. Always observe the lowest
respective value when determining the
maximum weight with which you can load
the vehicle and the trailer.
R The drawbar noseweight acting on the ball
coupling has to be added to the rear axle
weight in order to prevent the permissible
Gross Axle Weight Rating (GAWR) from
being exceeded. The permissible Gross
Vehicle Weight Rating (GVWR) is specified
on the type plate located on the B-pillar on
the driver's side of your vehicle.
i Mercedes-Benz recommends loading the
trailer so that the drawbar noseweight
remains between 8% and 10% of the
permissible gross trailer weight.
i The weight of additional accessories,
passengers, and cargo reduces the
permissible trailer load and drawbar
noseweight for your vehicle.
Checking the vehicle and trailer weight
R To check that the weights of the towing
vehicle and the trailer comply with the
maximum permissible values, have the
vehicle/trailer combination (including the
driver, passengers, and cargo with a fully
laden trailer) weighed on a calibrated
weighbridge.
R Check the gross axle weight rating of the
front and rear axle, the Gross Trailer Weight
(GTW), and the drawbar noseweight.
Trailer power supply
The trailer power socket of your vehicle is
designed for connecting the 7-pin connector
supplied as part of the Mercedes-Benz-
approved trailer coupling.
194Trailer towingDriving and parking

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops ( Y page 24).
Important safety notes
You will find an illustration of the instrument
cluster in the "At a glance" section
( Y page 29).
GWARNING
A driver's attention to the road and traffic
conditions must always be his/her primary
focus when driving.
For your safety and the safety of others,
selecting features through the multifunction
steering wheel should only be done by the
driver when traffic and road conditions permit
it to be done safely.
Bear in mind that at a speed of just 30 mph
(approximately 50 km/h ), your vehicle is
covering a distance of 44 feet (approximately
14 m) every second.
GWARNING
No messages will be displayed if either the
instrument cluster or the multifunction
display is inoperative.
As a result, you will not be able to see
information about your driving conditions,
such as
R speed
R outside temperature
R warning/indicator lamps
Rmalfunction/warning messages
R failure of any systems
Driving characteristics may be impaired.
If you must continue to drive, do so with added
caution. Contact an authorized Mercedes-
Benz Center as soon as possible.GWARNING
Malfunction and warning messages are only
indicated for certain systems and are
intentionally not very detailed. The
malfunction and warning messages are
simply a reminder with respect to the
operation of certain systems. They do not
replace the owner's and/or driver's
responsibility to maintain the vehicle's
operating safety. Have all required
maintenance and safety checks performed on
the vehicle. Bring the vehicle to an authorized
Mercedes-Benz Center to address the
malfunction and warning messages.
Displays and operation
Tachometer
The red band in the tachometer indicates the
engine's overrevving range.
! Do not drive in the overrevving range, as
this could damage the engine.
The fuel supply is interrupted to protect the
engine when the red band is reached.
Outside temperature display
The outside temperature display is in the
multifunction display ( Y page 200).
GWARNING
The outside temperature indicator is not
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose.
Indicated temperatures just above the
freezing point do not guarantee that the road
198Displays and operationOn-board computer and displays

surface is free of ice. The road may still be icy,
especially in wooded areas or on bridges.
Changes in the outside temperature are
displayed after a short delay.
Speedometer with segments
The segments in the speedometer indicate
which speed range is available.
DISTRONIC ( Y page 173) activated:
One or two segments in the set speed range
light up.
DISTRONIC detects a vehicle in front:
The segments between the speed of the
vehicle in front and the stored speed light up.
Operating the on-board computer
The on-board computer is activated as soon
as you turn the SmartKey to position 1 in the
ignition lock.
You can control the multifunction display and
the settings in the on-board computer using
the buttons on the multifunction steering
wheel.
:Multifunction display;~
Rejects or ends a call
Exits phone book/redial memory
6
Makes or accepts a call
Switches to the redial memory
WX
Selects submenus in the Settings
menu
Changes values
Adjusts the volume
?
Switches on the Voice Control
System; see the separate operating
instructions=VU
Selects a menu: scrolls back and
forth
A
Switches off the Voice Control
System; see the separate operating
instructions&*
Press briefly:
Scrolls back and forth within a menu
In the Audio menu: selects a stored
station, an audio track or a video
scene
In the Telephone menu: switches to
the phone book and selects a name
or a telephone number&*
Press and hold:
In the Audio menu: selects the
previous/next station or selects an
audio track using rapid scrolling
In the Telephone menu: starts rapid
scrolling through the phone bookDisplays and operation199On-board computer and displaysZ

Display messages
General information
GWARNING
All categories of messages contain important information which should be taken note of and,
where a malfunction is indicated, addressed as soon as possible at an authorized Mercedes-Benz
Center.
Failure to repair the condition noted may cause damage not covered by the Mercedes-Benz
Limited Warranty, or result in property damage or personal injury.
Display messages appear in the multifunction display.
Display messages with graphic displays may be shown in simplified form in the Operator's
Manual and may differ from the messages shown in the multifunction display.
Please respond in accordance with the display messages and follow the additional notes in
this Operator's Manual.
Certain display messages are accompanied by an audible warning tone or a continuous tone.
Hiding display messages
You can hide some display messages with a low priority.
XPress the V, U , & or * button on the steering wheel to select another display.
or
XPress the . reset button on the instrument cluster ( Y page 29).
The display message is cleared.
Display messages with a high priority are shown in red.
You cannot hide display messages of the highest priority. The multifunction display shows
these messages continuously until the causes for the messages have been remedied.
Message memory menu
The on-board computer saves certain display messages. You can call up the display messages
in the message memory menu.
The message memory menu is only shown if any display messages have been stored.
XPress the V or U button repeatedly, until either the original menu or the message
memory menu is shown.
If there are display messages, the multifunction display shows, for example, 2 Messages.XPress the & or * button to scroll through the display messages.
When the ignition is switched off, all display messages are deleted apart from some high-
priority display messages. Once the causes of the high-priority display messages have been
rectified, the corresponding display messages are also deleted.
Display messages213On-board computer and displaysZ

Safety systemsDisplay messagesPossible causes/consequences and M Solutions!÷
Unavailable See
Operator's ManualGRisk of accident
ABS (Anti-lock Braking System), ESP ®
(Electronic Stability
Program), BAS (Brake Assist), PRE-SAFE ®
, hill start assist and
ESP ®
trailer stabilization are temporarily not available.
In addition, the ÷, å and ! warning lamps light up in
the instrument cluster.
The self-diagnosis function might not be complete, for example.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XCarefully drive a suitable distance making slight steering
movements at a speed above 12 mph (20 km/h).
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
XDrive on carefully.XVisit a qualified specialist workshop.GRisk of accident
ABS, ESP ®
, BAS, PRE-SAFE ®
, hill start assist and ESP ®
trailer
stabilization are temporarily not available.
In addition, the ÷, å and ! warning lamps light up in
the instrument cluster.
For example, the on-board voltage may be insufficient.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XDrive on carefully.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
XDrive on carefully.XVisit a qualified specialist workshop.214Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutions!÷
Inoperative See
Operator's ManualGRisk of accident
ABS, ESP ®
, BAS, PRE-SAFE ®
, hill start assist and ESP ®
trailer
stabilization are not available due to a malfunction.
The $ (USA only)/ J (Canada only), ÷, å and !
warning lamps in the instrument cluster also light up.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XDrive on carefully.XVisit a qualified specialist workshop immediately.÷
Unavailable See
Operator's ManualGRisk of accident
ESP ®
, PRE-SAFE ®
and BAS, hill start assist and ESP ®
trailer
stabilization are temporarily not available.
In addition, the ÷ and å warning lamps light up in the
instrument cluster.
The self-diagnosis function might not be complete, for example.
The brake system continues to function normally, but without the
functions listed above.
XCarefully drive on a suitable stretch of road, making slight
steering movements, at a speed above 20 km/h.
If the display message disappears, ESP ®
is available again.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
XDrive on carefully.XVisit a qualified specialist workshop.ESP ®
, PRE-SAFE ®
and BAS, hill start assist and ESP ®
trailer
stabilization are temporarily not available.
In addition, the ÷ and å warning lamps light up in the
instrument cluster.
For example, the on-board voltage may be insufficient.
The brake system continues to function normally, but without the
functions listed above.XDrive on carefully.XVisit a qualified specialist workshop immediately.Display messages215On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsIf the display message is shown while the vehicle is in motion and
the ÷ warning lamp flashes, the electronic traction system is
deactivated. Otherwise, the brakes on the drive wheels could
overheat.XLet the brakes cool down until the display message disappears
and the ÷ warning lamp goes out.
The electronic traction system is active again.÷
Inoperative See
Operator's ManualGRisk of accident
ESP ®
, PRE-SAFE ®
and BAS, hill start assist and ESP ®
trailer
stabilization are not available due to a malfunction.
In addition, the ÷ and å warning lamps light up in the
instrument cluster.
The brake system continues to function normally, but without the
functions listed above.
XDrive on carefully.XVisit a qualified specialist workshop immediately.T !
÷
Inoperative See
Operator's ManualGRisk of accident
EBD (electronic brake force distribution), ABS, ESP ®
, BAS,
PRE-SAFE ®
, hill start assist and ESP ®
trailer stabilization are not
available due to a malfunction.
In addition, the ÷, å and ! warning lamps light up in
the instrument cluster and a warning tone sounds.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XDrive on carefully.XVisit a qualified specialist workshop immediately.#
Brake WearThe brake pads/linings have reached their wear limit.XVisit a qualified specialist workshop.216Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutions$ (USA
only) ! (Canada
only)
Release Parking
BrakeYou are driving with the parking brake applied. A warning tone also
sounds.XRelease the parking brake$ (USA
only) J (Canada
only)
Check Brake Fluid
LevelGRisk of accident
There is not enough brake fluid in the brake fluid reservoir.
Additionally, the red $ (USA only)/ J (Canada only)
warning lamp lights up in the instrument cluster and a warning
tone sounds.
XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.XEngage the parking brake.XConsult a qualified specialist workshop.XDo not add brake fluid. This will not correct the malfunction.GWARNING
Driving with the message Check Brake Fluid Level displayed can result in an accident. Have
your brake system checked immediately.
Do not add brake fluid before checking the brake system. Overfilling the brake fluid reservoir can
result in spilling brake fluid on hot engine parts and the brake fluid catching fire. You can be
seriously burned.
Display messages217On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsG
Tele Aid
InoperativeUSA only: one or more of the main functions in the mbrace system
are malfunctioning.
Canada only: one or more of the main functions of the TELEAID
system are malfunctioning.XUSA only: have the mbrace system checked at a qualified
specialist workshop.XCanada only: have the TELEAID system checked at a qualified
specialist workshop.PRE-SAFE
Inoperative See
Operator's ManualGRisk of injury
Important functions of PRE-SAFE ®
have failed. All other occupant
safety systems, e.g. air bags, remain available.
XVisit a qualified specialist workshop immediately.+
Restraint Sys.
Malfunction
Service RequiredGRisk of injury
There is a malfunction in the SRS (Supplemental Restraint
System).
XVisit a qualified specialist workshop immediately.GWARNING
In the event a malfunction of the SRS is indicated as outlined above, the SRS may not be
operational.
For your safety, we strongly recommend that you contact an authorized Mercedes-Benz Center
immediately to have the system checked. Otherwise the SRS may not be activated when needed
in an accident, which could result in serious or fatal injury, or it might deploy unexpectedly and
unnecessarily which could also result in injury.
218Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M SolutionsFront Passenger
Airbag Enabled
See Operator's
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.XEngage the parking brake.XSwitch off the ignition.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 no objects are exerting force on the seat, e.g.:
R trapped books, bags, etc. lying on, behind or beside the seat
R head restraints pressing against the headliner
The system may otherwise detect these forces 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 44) 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 44) has deactivated
the front-passenger air bag.
R the Front Passenger Airbag Enabled See Operator's
Manual or Front Passenger Airbag Disabled See
Operator's 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 these conditions are met, the front-passenger seat can be
occupied again. Whether the 42 indicator lamp
remains lit or goes out depends on how OCS classifies the
occupant.
If the conditions are not met, the system is not operating correctly.
Display messages219On-board computer and displaysZ