2018 MERCEDES-BENZ A-CLASS SALOON check engine

Display messages
Possible causes/consequences and M
MSolutions &
WARNING Risk of an accident from driving wi thove rheated tyres
Overheated tyres may bur st, particularly at high speeds. #
Reduce speed so that the tyres cool down. #
Reduce speed so that the tyres cool down.
Check tyre pressures then
restart Run Flat Indicator *T
he tyre pressure loss warning sy stem generated a displ aymessa geand has not been restar ted since. #
When the tyre pressure is cor rect, restart the tyre pressure loss warning sy stem (/ page478).
Run Flat Indicator inopera-
tive *T
he tyre pressure loss warning sy stem is malfunctioning. #
Consult a qualified specialist workshop. Key
Display messages
Possible causes/consequences and M MSolutions
Á Key not detected (red dis‐
play message) *T
hekey cannot be de tected and may no longer be in theve hicle.
The key is no lon ger in theve hicle and you swit choff the engine:
R You can no lon gerst art the engine.
R You cannot centrally lock theve hicle. #
Ensure that theke y is in theve hicle. Display messages and
warning/indicator lamps 549

Display messages
Possible causes/consequences and M
MSolutions
ï Check trailer hitch lock
(white display message) *T
he trailer tow hit chis not operational when you are driving with a trailer. #
Stop theve hicle immediately, paying attention toroad and traf fic conditions, and switch off the engine. #
Uncouple the trailer and secure it against rolling away. #
Initiate a new swivelling procedure (/ page248). #
Ifth e ball neck is extended, press and hold the button on theta ilgate until the ball neck engages beneath the
bumper. #
When the display message disappears, couple up the trailer and drive on. &
WARNING Risk of an accident if the ball neck is not loc ked
If th e ball neck is not in the loc ked position, the trailer may come loose. #
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. #
Uncouple the trailer and secure it against rolling away. #
Initiate a new swivelling procedure and do not re-couple the trailer until the display message disappears. If
th e display message does not disappear, the trailer tow hit chis defective and the ball neck is not loc ked. #
Do not couple up the trailer. Drive on without the trailer. No tethere duced ground clearance due tothe
unlo cked ball nec k. #
Consult a qualified specialist workshop.
The trailer tow hit chis not operational when theve hicle is at a standstill. 552
Display messages and warning/indicator lamps

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
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. #
Obser vethe messages on the multifunction displa y. #
Consult a qualified specialist workshop.
! ABS warning lamp The
yellow ABS warning lamp is lit while the engine is running.
ABS is malfunctioning.
If th ere is an additional warning tone, EBD is malfunctioning.
Other driving sy stems and driving saf ety sy stems may also be malfunctioning. &
WARNING Thereisrisk of skidding if EBD or ABS is malfunctioning
If EBD or ABS is malfunctioning, the wheels could lock when braking
The steering capability and braking characteristics are thus se verely impaired. The braking dis tance may increase in
an emergency braking situation. In addition, other driving saf ety sy stems are switched off. #
Drive on carefull y. #
Have the brake sy stem checked immediately at a qualified specialist workshop. #
Drive on carefully. #
Obser vethe messages on the multifunction displa y. #
Consult a qualified specialist workshop. Display messages and
warning/indicator lamps 563

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
! Re d indicator lamp, elect ric
parking brake applied
!
Ye llow elect ric pa rking
brake indicator lamp is mal‐
functioning The
red elect ric pa rking brake indicator lamp flashes or is lit. The yellow indicator lamp is also lit if the electric parking
brake malfunctions. #
Obser vethe messages on the multifunction displa y.
J
Brake sy stem warning lamp
(yellow) The
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. #
Adjust your speed and continue todrive carefull y,leaving a suitable dis tance totheve hicle in front. #
Ifth e multifunction display sho wsa display message, please obse rveth is. 564
Display messages and warning/indicator lamps

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
Have there stra int sy stem checked and repaired immediately at a qualified specialist workshop. #
Drive on carefully. #
Obser vethe messages on the multifunction displa y. #
Consult a qualified specialist workshop immediatel y. Seat belt
Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
7 Seat belt warning lamp
lights up The
red seat belt warning lamp will light up once the engine has star ted.
In addition, a warning tone may sound.
The seat belt warning lamp reminds the driver and front passenger tofast entheir seat belts. #
Fasten your seat belt (/ page37).
If yo u ha veplaced objects on the front passenger seat, the seat belt warning lamp may remain lit.
7 Seat belt warning lamp
fl ashes The
red seat belt warning lamp flashes and an intermit tent wa rning tone sounds.
The driver or front passenger has not fastened their seat belt while theve hicle is in motion. #
Fasten your seat belt(/ page37).
There are objects on the front passenger seat. #
Remo vethe objects from the front passenger seat. Display messages and
warning/indicator lamps 567

Driving sy
stems Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
L Wa rning lamp for dis tance
wa rning function The
red dis tancewarning lamp lights up while theve hicle is in motion.
The dis tance totheve hicle in front is too small forth e speed selected.
If th ere is an additional warning tone, you are approaching an obs tacle at too high a speed. #
Be prepared tobrake immediatel y. #
Increase the dis tance.
Fu nction of Active Brake Assi st .Engine
Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
; Engine diagnosis warning
lamp The
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 eme rgency 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. 568
Display messages and warning/indicator lamps

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
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.
æ Fu elreser ve wa rning lamp The
yellow fuel reser ve wa rning lamp lights up while the engine is running.
The fuel supp lyhas dropped into there ser verange. #
Refuel.
#
Electrical fault warning
lamp The
red elect rical fault warning lamp is lit.
There is a fault in the electrics. #
Obser vethe messages on the multifunction displa y.
?
Coolant warning lamp The
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
If th ere is an additional warning tone, the coolant temp erature has exceeded 120 °C. Displ
aymessa ges and warning/indicator lamps 569

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions &
WARNING Danger of bu rns when opening the bonn et
If yo u open the engine bonn etwhen the engine has overheated or during a fire inthe engine compartment, you
could come into contact wi thhot gases or other escaping operating fluids. #
Before opening the bonn et, allow the engine tocool down. #
Intheeve nt of a fire inthe engine compartment, keep the engine bonn etclosed and call thefire service. #
Stop theve hicle immediately, paying attention toroad and traf fic conditions, and switch off the engine. Do not con‐
tinue driving under any circums tances. #
Obser vethe messages on the multifunction 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.
or #
Exit theve hicle and keep a safe dis tance from it until the engine has cooled down. #
Check the coolant le vel (/ page 435). #
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. 57 0
Displaymessa ges and warning/indicator lamps