MERCEDES-BENZ S-Class 2012 W221 Owner's Manual

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.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 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 50) 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 50) 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 messages399On-board computer and displaysZ

GWARNING
If the 42 indicator lamp remains off even after performing the above corrective
steps, do not have any children 12 years old and under and other small individuals use the front-
passenger seat until the system has been repaired.
Display messagesPossible causes/consequences and M SolutionsFront Passenger
Airbag Disabled
See Oper. ManualThe front-passenger air bag is deactivated during the journey even
though an adult or a person larger than a certain size is occupying
the front-passenger seat. If additional forces are applied to the
seat, the system may interpret the occupant's weight as lower
than it actually is.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.XHave the occupant get out of the vehicle.XKeep the seat unoccupied, close the front-passenger door and
switch on the ignition.
Observe the 42 (Y page 50) 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 50) 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 these conditions are fulfilled, 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 fulfilled, the system is not operating
correctly.
XVisit a qualified specialist workshop immediately.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.
400Display messagesOn-board computer and displays

Lights
i Display messages about LEDs:
This display message will only appear if all LEDs have failed.Display messagesPossible causes/consequences and M Solutionsb
Check Left
Cornering
Light or Check
Right Cornering
Light The left or right-hand cornering light is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Left Low
Beam or Check Right
Low Beam The left or right-hand low-beam headlamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Rear Left
Turn
Signal or Check
Rear Right Turn
SignalThe rear left-hand or rear right-hand turn signal is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Front Left
Turn
Signal or Check
Front Right Turn
SignalThe front left-hand or front right-hand turn signal is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Left Mirror
Turn
Signal or Check
Right Mirror Turn
SignalThe 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 282).
or
XVisit a qualified specialist workshop.Display messages401On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutionsb
Check Center Brake
LampThe high-mounted brake lamp is faulty.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Left Tail
and Brake
Lamp or Check Right
Tail and Brake LampThe left or right-hand tail lamp/brake lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Left High
Beam or Check Right
High BeamThe left or right-hand high beam is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Left License
Plate Lamp or Check
Right License
Plate LampThe left or right-hand license plate lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Left Fog
Lamp or Check Right
Fog LampThe left-hand or right-hand front fog lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Rear Left
Fog Lamp or Check
Rear Right Fog LampThe left-hand or right-hand rear fog lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Front Left
Parking
Lamp or Check Front
Right Parking LampThe front left or front right parking or standing lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.402Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutionsb
Check Left Reverse
Lamp or Check Right
Reverse LampThe left or right-hand backup lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Front Left
Sidemarker
Lamp or Check Front
Right Sidemarker
LampThe left or right front side marker lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Rear Left
Sidemarker
Lamp or Check Rear
Right Sidemarker
LampThe rear left or right side marker lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Left Daytime
Running
Light or Check
Right Daytime
Running Light The left or right-hand daytime running lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Active Headlamps
InoperativeThe active light function is defective.XVisit a qualified specialist workshop.b
Malfunction See
Oper. ManualThe exterior lighting is defective.XVisit a qualified specialist workshop.b
AUTO Lamp Function
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 385).XSwitch the lights on and off using the light switch.Display messages403On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutionsb
Please Switch Off
LightsThe lights are still switched on when you leave the vehicle. A
warning tone also sounds.XTurn the light switch to $ or c .
or
XIf the rear fog lamp is switched on: press the light switch in to
the stop.Adaptive High-beam
Assist inoperativeAdaptive Highbeam Assist is defective.XVisit a qualified specialist workshop.
Engine
Display messagesPossible causes/consequences and M Solutions+
Check Coolant
Level See Oper.
ManualThe coolant level is too low.XAdd coolant, observing the warning notes when doing so
( Y page 460).XIf coolant needs to be added 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.
404Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M Solutions?
Coolant Low Stop
Vehicle Turn
Engine OffThe coolant is too hot.XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.XMake sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.XWait until the display message disappears before restarting the
engine. Otherwise, there is a risk of engine damage.XPay attention to the coolant temperature display.XIf the temperature increases again, visit a qualified specialist
workshop immediately.The poly-V-belt may have torn.XPull 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 not damaged:
XWait until the display message disappears before restarting the
engine. Otherwise, there is a risk of engine damage.XPay attention to the coolant temperature display.XVisit a qualified specialist workshop.GWARNING
Driving when your engine is overheated can cause some fluids which may have leaked into the
engine compartment to catch fire. You could be seriously burned.
Steam from an overheated engine can cause serious burns which can occur just by opening the
engine hood. Stay away from the engine if you see or hear steam coming from it.
Stop the vehicle in a safe location away from other traffic. Turn off the engine, get out of the
vehicle and do not stand near the vehicle until the engine has cooled down.
! If the coolant temperature exceeds 248 ‡(120 †) do not continue driving. The engine will
otherwise be damaged.
Display messages405On-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 not damaged:
XVisit a qualified specialist workshop.4
Check Engine Oil
at Next RefuelingVehicles with an oil dipstick: the oil level has dropped to the
minimum level.XCheck the engine oil level at the latest when next refueling
( Y page 457).XIf necessary, add engine oil ( Y page 459).XIf engine oil needs to be added more often than usual, have the
engine checked at a qualified specialist workshop.4
Check Engine Oil
Level (Add 1 quart)
(USA only) Check
Engine Oil Level
(Add 1 Liter)
(Canada only)Vehicles without an oil dipstick: the engine oil level is too low.XCheck the oil level ( Y page 457).XIf necessary, add engine oil ( Y page 457).XIf engine oil needs to be added more often than usual, have the
engine checked at a qualified specialist workshop.
Information on approved engine oils can be obtained from any qualified specialist workshop
or on the Internet at http://www.mbusa.com (USA only).
406Display messagesOn-board computer and displays

! 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 messagesPossible causes/consequences and M Solutions4
Engine Oil Level
Low Stop Vehicle
Turn Engine OffVehicles without an oil dipstick: the engine oil level is too low.
There is a risk of engine damage.XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.XApply the parking brake.XAdd engine oil ( Y page 459) and check the oil level
( Y page 457).4
Engine Oil Level
Too HighVehicles without an oil dipstick: you have added too much engine
oil. There is a risk of damage to the engine or to the catalytic
converter.XHave the excess oil siphoned off at a qualified specialist
workshop. Observe the legal requirements.4
Engine Oil Level
Cannot Be MeasuredVehicles without an oil dipstick: the measuring system is
defective.XVisit a qualified specialist workshop.8
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 LooseThe 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).Display messages407On-board computer and displaysZ

Display messagesPossible causes/consequences and M Solutions¸·
Replace Air FilterVehicles with a diesel engine: the engine air filter is dirty and must
be replaced.XVisit a qualified specialist workshop.!
Check 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
Oper. ManualThe DEF tank is empty.XHave the DEF tank filled as soon as possible at a qualified
specialist workshop ( Y page 321).Ø
Remaining Starts:
16The DEF level has fallen to a minimum.XHave the DEF tank filled immediately at a qualified specialist
workshop. ( Y page 321)
Driving systems
Display messagesPossible causes/consequences and M SolutionsÀ
Attention Assist:
Pause!Based on specific criteria, ATTENTION ASSIST 21
has determined
that the driver is tired or paying less attention. A warning tone also
sounds.XIf necessary, take a break.
During long journeys, take regular breaks in good time so you get
enough rest.
À
Attention Assist
InoperativeATTENTION ASSIST 21
has failed.XVisit a qualified specialist workshop.Á
Night View Assist
InoperativeNight View Assist Plus is defective.XVisit a qualified specialist workshop.21 Not available on hybrid vehicles.408Display messagesOn-board computer and displays