2012 MERCEDES-BENZ R-Class page 1

GWARNING
If the 42 indicator lamp remains lit with an adult occupant on the front-passenger
seat even after performing the above corrective steps, do not have any passenger use the front-
passenger seat until the system has been repaired.
Lights
i Display messages about LEDs:
This display message will only appear if all LEDs have failed.
Display messagesPossible causes/consequences and M Solutionsb
Low Beam Left
or Low Beam RightThe left or right-hand low-beam headlamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
Trailer Tail Lamp
Left or Trailer
Tail Lamp RightThe left or right-hand trailer tail lamp is faulty.XCheck whether you are permitted to change the bulb yourself.
or
XVisit a qualified specialist workshop.b
Trailer Turn
Signal Left or
Trailer Turn
Signal RightThe left or right-hand trailer turn signal lamp is defective.XCheck whether you are permitted to change the bulb yourself.
or
XVisit a qualified specialist workshop.b
Trailer Brake LampThe trailer brake lamp is defective.XCheck whether you are permitted to change the bulb yourself.
or
XVisit a qualified specialist workshop.b
Turn Signal Rear
Left or Turn Signal
Rear RightThe rear left-hand or rear right-hand turn signal is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.222Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutionsb
Turn Signal Front
Left or Turn Signal
Front RightThe front left-hand or front right-hand turn signal is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
Turn Signal Left
Mirror or Turn
Signal Right MirrorThe turn signal in the left-hand or right-hand exterior mirror is
defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
3rd Brake LampThe high-mounted brake lamp is faulty.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
Brake Lamp Left
or Brake Lamp RightThe left or right-hand brake lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
High Beam Left
or High Beam RightThe left or right-hand high beam is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
License Plate Lamp
Left or License
Plate Lamp RightThe left or right-hand license plate lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.Display messages223On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutionsb
Front Foglamp Left
or Front Foglamp
RightThe left-hand or right-hand front fog lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
Foglamp Rear Left
or Foglamp Rear
RightThe left-hand or right-hand rear fog lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
Standing Lamp
Front Left
or Standing Lamp
Front RightThe front left or front right standing lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
Reverse Lamp Left
or Reverse Lamp
RightThe left or right-hand backup lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
Marker Lamp Front
Left or Marker Lamp
Front RightThe left or right front side marker lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
Tail Lamp Left
or Tail Lamp RightThe left or right-hand tail lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.b
Daytime Running
Light Left
or Daytime Running
Light RightThe left or right-hand daytime running lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 119).
or
XVisit a qualified specialist workshop.224Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutionsb
AUTO Light
InoperativeThe light sensor is defective.XVisit a qualified specialist workshop.
USA only:
XSwitch off the daytime running lamps in the on-board computer
( Y page 206).XSwitch the lights on and off using the light switch.b
Switch Off LightsThe lights are still switched on when you leave the vehicle. A
warning tone also sounds.XTurn the light switch to $ or à .
or
XIf the rear fog lamp is switched on: press the light switch in to
the stop.
Engine
Display messagesPossible causes/consequences and M Solutions+
Top Up Coolant See
Operator's ManualThe coolant level is too low.XAdd coolant, observing the warning notes when doing so
( Y page 285).XIf the coolant needs to be refilled more often than usual, have
the engine coolant system checked at a qualified specialist
workshop.GWARNING
Do not spill antifreeze on hot engine parts. Antifreeze contains ethylene glycol which may burn
if it comes into contact with hot engine parts. You could be seriously burned.
! The coolant level is too low. Avoid making long journeys with too little coolant in the cooling
system. The engine will otherwise be damaged.
The display messages and the corresponding symbol that indicate that the coolant level is
too low must not be ignored.
Display messages225On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutions?The engine fan is defective.XAt coolant temperatures under 248 ‡ (120 †), drive to the next
qualified specialist workshop.XAvoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic.#The battery is not being charged.
Possible causes are:
R a defective alternator
R a torn poly-V-belt
R a malfunction in the electronicsXPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.XOpen the hood.XCheck whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not continue driving. The engine could otherwise overheat.
XConsult a qualified specialist workshop.
If the poly-V-belt is OK:
XVisit a qualified specialist workshop.#
Battery /
Alternator Stop
VehicleThe battery is defective.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.4
Check engine oil
level at next
refuelingThe oil level is too low.XCheck the oil level ( Y page 283).XIf necessary, add engine oil ( Y page 284).XHave the engine checked for leaks if the engine oil needs to be
refilled more often than usual.
Information on approved engine oils can be obtained from any qualified specialist workshop
or on the Internet at http://www.mbusa.com (USA only).
! The oil level is too low. Avoid long journeys with too little engine oil. There is a risk of
engine damage.
The display messages and the corresponding symbol that indicate that the oil level is too
low must not be ignored.
Display messages227On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutions8
Reserve FuelThe fuel level has dropped into the reserve range.XRefuel at the nearest gas station.CThere is only a very small amount of fuel in the fuel tank.XRefuel at the nearest gas station without fail.8
Gas Cap OpenThe fuel system pressure is too low. The fuel filler cap is not closed
correctly or the fuel system is leaking.XCheck that the fuel filler cap is correctly closed.
If the fuel filler cap is not correctly closed:
XClose the fuel filler cap.
If the fuel filler cap is correctly closed:
XVisit a qualified specialist workshop.8
Ultra Low-sulfur
Diesel Fuel OnlyVehicles with a diesel engine: the fuel level has fallen below the
reserve range.XRefuel at the nearest gas station.XOnly use commercially available vehicular ULTRA-LOW SULFUR
HIGHWAY DIESEL FUEL (ULSD, 15 ppm SULFUR MAXIMUM).¸
Replace air filterVehicles with a diesel engine: the engine air filter is dirty and must
be replaced.XVisit a qualified specialist workshop.·
Clean Fuel FilterVehicles with a diesel engine: there is water in the fuel filter. The
water must be drained off.XVisit a qualified specialist workshop.Ø
Check Additive See
Operator's ManualThe DEF tank is empty.XHave the DEF tank filled as soon as possible at a qualified
specialist workshop ( Y page 161).Ø
Remaining Starts:
16The DEF level has fallen to a minimum.XHave the DEF tank filled immediately at a qualified specialist
workshop. ( Y page 161)228Display messagesOn-board computer and displays

Driving systemsDisplay messagesPossible causes/consequences and M Solutions°
Vehicle Rising
Wait brieflyThe vehicle level is too low when the vehicle is stationary.XDo not pull away.
The vehicle level is set when the display message disappears.°
STOP Car Too LowGRisk of accident
You have pulled away while the vehicle level is still too low or
AIRMATIC is defective.
AIRMATIC sets the vehicle to the selected level after a short
period. While the display message is displayed:
XMake only slight steering movements. Otherwise, the front
fender or the tires could be damaged if the steering movement
is too large.XListen for scraping sounds.XDo not drive faster than 50 mph (80 km/h).
If the display message continues to be displayed:
XHave the vehicle checked at a qualified specialist workshop.°
Level Selection
Not PermittedYou cannot change the vehicle level because you are exceeding
the permissible speed for the selected vehicle level.XDrive more slowly and then select the desired vehicle level again
( Y page 180).°
Compressor Cooling
DownYou have selected a higher vehicle level. The compressor first
needs to cool down because of frequent level changes.XDrive in a manner appropriate for the current vehicle level.XMake sure that there is sufficient ground clearance.XAllow the compressor to cool down.
When the compressor has cooled down, the display message
disappears. The vehicle then continues rising to the selected
level.°
MalfunctionAIRMATIC is malfunctioning.XDo not drive faster than 50 mph (80 km/h).XMake sure that there is sufficient ground clearance.XHave the vehicle checked at a qualified specialist workshop.Display messages229On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsBlind Spot Assist
Currently
Unavailable, See
Operator's ManualBlind Spot Assist is temporarily inoperative if:
R the sensors are dirty.
R its function is impaired due to heavy rain or snow.
R the radar sensor system is outside the operating temperature
range.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations or other sources of electromagnetic radiation.
The yellow 9 indicator lamps also light up in the exterior
mirrors.
Blind Spot Assist is operational again and the display message
disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensors are fully available again.
R the radar sensor system is back within the operating
temperature range.
If the display message continues to be displayed:XClean the sensors ( Y page 291).XRestart the engine.Blind Spot Assist
InoperativeBlind Spot Assist is defective.
The yellow 9 indicator lamps also light up in the exterior
mirrors.XVisit a qualified specialist workshop.Cruise Control
InoperativeCruise control is defective.XVisit a qualified specialist workshop.Cruise Control
--- MPH A condition for activating cruise control has not been fulfilled.
You attempted to save a speed of less than 20 mph (30 km/h).XIf the situation allows, drive faster than 20 mph ( 30 km/h) and
save the speed.XCheck the activation conditions for cruise control
( Y page 170).DISTRONIC
--- MPH An activation condition for DISTRONIC is not fulfilled.XCheck the activation conditions for DISTRONIC ( Y page 173).DISTRONIC
OverrideDISTRONIC is no longer controlling the speed of the vehicle.XTake your foot off the accelerator pedal.230Display messagesOn-board computer and displays