2020 MERCEDES-BENZ S-CLASS SALOON LONG engine

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
ü Seat belt warning lamp
fl ashes *T
he red seat belt warning lamp flashes and an intermit tent wa rning tone sounds.
The driver or front passenger has not fastened his/her seat belt while theve hicle is in motion. #
Fasten your seat belt (/ page 45).
There are objects on the front passenger seat. #
Remo vethe objects from the front passenger seat.
ü
Seat belt warning lamp
lights up *T
he red seat belt warning lamp lights up once the engine has star ted.
In addition, an intermittent warning tone may sound.
The red seat belt warning lamp reminds the driver and front passenger tofasten their seat belts. #
Fasten your seat belt (/ page 45).
If yo u ha veplaced objects on the front passenger seat, there d seat belt warning lamp may remain lit. Ve
hicle Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
ï Tr ailer tow hit chwarning
lamp *T
hered trailer hitch warning lamp is lit.
The trailer hitch is not operational or is swivelling. &
WARNING Risk of an accident if the ball neck is not loc ked
The trailer may become de tach ed. 552
Display messages and warning/indicator lamps

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
Stop theve hicle immediately in accordance with the traf fic conditions. Do not continue driving. #
Uncouple the trailer and secure it against rolling away. #
Initiate a new swivel mo vement and do not re-couple the trailer until thewa rning/indicator lamp goes out. #
Notethe messages on the driver displa y.
If th e trailer hitch is swivelling: #
Wait until the ball neck has reached the operational position.
Ù
Po we rst eering warning
lamp (yellow) *T
he yellow po werst eering warning lamp is lit when the engine is running.
The po wer assi stance or thesteering itself is malfunctioning. #
Notethe messages on the driver displa y.
Ù Po we rst eering warning
lamp (red) *T
he red po werst eering warning lamp is lit while the engine is running.
The po wer assi stance or thesteering itself is malfunctioning. &
WARNING Risk of accident if steering capability is impaired
If th esteering does not function as intended, theve hicle's operating saf ety is jeopardised. #
Pull over and stop theve hicle safely as soon as possible, paying attention toroad and traf fic conditions. Do
not continue driving under any circums tances. Display messa
ges and warning/indicator lamps 553

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
Consult a qualified specialist workshop. #
Notethe messages on the driver displa y.
Ù Re ar axle steering warning
lamp (yellow) *T
he yellow rear axle steering warning lamp is lit while the engine is running.
The rear axle steering is malfunctioning. #
Notethe messages on the driver displa y.
Ù Re ar axle steering warning
lamp (red) *T
he redre ar axle steering warning lamp is lit while the engine is running.
The rear axle steering is malfunctioning. &
WARNING Risk of accident if steering capability is impaired
If th esteering does not function as intended, theve hicle's operating saf ety is jeopardised. #
Pull over and stop theve hicle safely as soon as possible, paying attention toroad and traf fic conditions. Do
not continue driving under any circums tances. #
Consult a qualified specialist workshop. #
Notethe messages on the driver displa y.554
Display messages and warning/indicator lamps

Engine
Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
ÿ Coolant warning lamp (red) *T
he red coolant warning lamp is lit while the engine is running.
Po ssible causes:
R The temp erature sensor is malfunctioning
R The coolant le vel is too low
R The air supply tothera diator is obstructed
R The radiator fan is faulty
R The engine coolant pump is faulty
If th ere is an additional warning tone, the coolant temp erature has exceeded 120°C. &
WARNING Risk of bu rns when opening the bonn et
If yo u open the bonn etwhen the engine has overheated or when there is a fire inthe engine compartment, the
fo llowing situations may occur:
R You could come into contact with hot gases.
R You could come into contact with other hot, escaping operating fluids. #
Before opening the bonn et, allow the engine tocool down. #
Intheeve nt of a fire inthe engine compartment, keep the bonn etclosed and call thefire service. Display messages and
warning/indicator lamps 555

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
Stop theve hicle immediately in accordance with the traf fic conditions and switch off the engine. Do not continue
driving. #
Notethe messages on the driver displa y.
If th e coolant temp erature display is at the lo wer end of thete mp erature scale: #
Consult a qualified specialist workshop.
If th e coolant temp erature display is at the upper end of thete mp erature scale: #
Exit theve hicle and keep a safe dis tance from it until the engine has cooled down. #
Make sure that the air supply tothera diator is not obstructed. #
Avoiding high loads on the engine, drive tothe nearest qualified specialist workshop. In doing so, ensure that the
coolant temp erature display remains below 120°C.
ÿ Coolant warning lamp (yel‐
low) *T
he yellow coolant warning lamp is lit while the engine is running.
Po ssible causes:
R The temp erature sensor is malfunctioning
R The charge air, transmission oil or bat tery cooling is faulty
R The radiator shutters are bloc ked or defective #
Avoiding high loads on the engine, drive tothe nearest qualified specialist workshop. 556
Display messages and warning/indicator lamps

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
; Engine diagnosis warning
lamp *T
he yellow engine diagno stics warning lamp is lit while the engine is running.
A malfunction has occu rred in the engine, theex haust sy stem or the fuel sy stem.
The emissions limit value may ha vebeen exceeded and the engine may be running in emergency operation mode. #
Have theve hicle checked as soon as possible at a qualified specialist workshop.
Ve hicles with a diesel engine: the fuel tank may ha vebeen run dr y. #
Start the engine thre eto four times af terre fuelling.
If th eye llow engine diagnosis warning lamp goes out, emer gency operation mode is cancelled. The vehicle need
not be checked.
#
Elect rical fault warning
lamp *T
hered elect rical fault warning lamp is lit.
There is a fault in the electrics. #
Notethe messages on the driver's displa y.
8
Fu elreser ve wa rning lamp
lights up *T
he yellow fuel reser vewarning lamp lights up while the engine is running.
The fuel supply has dropped into there ser verange. #
Refuel. Displ
aymessa ges and warning/indicator lamps 557

Brakes
Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
! Elect ric pa rking brake indi‐
cator lamp (red)
!
The elect ric pa rking brake
(yellow) indicator lamp *T
he red elect ric pa rking brake indicator lamp flashes or is lit.
The yellow elect ric pa rking brake indicator lamp also lights up in theev ent of a malfunction. #
Notethe messages on the driver's displa y.
J
Brake sy stem warning lamp
(yellow) *T
he yellow brake sy stem warning lamp is lit while the engine is running. &
WARNING Risk of an accident due toa brake sy stem malfunction
If th e brake sy stem is malfunctioning, braking characteristics may be impaired. #
Drive on carefull y. #
Have the brake sy stem checked immediately at a qualified specialist workshop. The hill
start assist may be malfunctioning. #
Adjust your speed and drive on carefull y,leaving a suitable dis tance totheve hicle in front. 558
Display messages and warning/indicator lamps

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
Ifth e driver's display sho wsa display message, obse rve it. #
Consult a qualified specialist workshop.
J Brake sy stem warning lamp
(red) *T
he red brake sy stem warning lamp is lit while the engine is running.
Po ssible causes:
R The brake forc e boosting is malfunctioning and the braking characteristics may be af fected.
R The reis insuf ficient brake fluid in the brake fluid reser voir. #
Notethe messages on the driver's displa y. &
WARNING Risk of accident and inju ryif brake forc e boosting is malfunctioning
If brake forc e boosting is malfunctioning, increased brake pedal forc e may be necessary for braking. The braking
ch aracteristics may be impaired. The braking dis tance can increase in emergency braking situations. #
Stop in a safe location immediately. Do not continue driving! #
Consult a qualified specialist workshop. &
WARNING Risk of an accident due tolow brake fluid le vel
If th e brake fluid le vel is too lo w,the braking ef fect and the braking characteristics may be impaired. #
Stop theve hicle as soon as possible, paying attention toroad and traf fic conditions. Do not continue driv‐
ing. Display messages and
warning/indicator lamps 559