2018 MERCEDES-BENZ CLA warning

Display messages
Possible causes/consequences and P Solutions
Radar Sensor s Dirty
See Operator' sM an ‐
ual The radar sensor system is malfunctioning .
Possibl ec auses are: R
Dirt on sensor sR
Heavy rain or snow R
Whe nd rivin goni nter-urban roads without traffic or infrastructure,
e.g. in desert-like area s
At least on ed rivin gs ystem or drivin gs afet ys ystem is malfunctioning
or is temporarily unavailable :R
Active Brake Assis tR
Distanc eP ilo tD ISTR ONI C
Aw arning tone also sounds.
Once th ec aus eoft he problem is no longer present, th ed rivin ga nd
drive safet ys ystems will be available again .T he display message dis-
appears.
If th ed isplay message does no td isappear :X
Pull ove ra nd stop th ev ehicl es afely as soo nasp ossible, payin g
attention to roa da nd traffic conditions.X
Secur et he vehicl ea gainst rollin ga way ( Y
page 141).X
Switc ho ff th ee ng ine.X
Clean all sensor s( Y
page 265).X
Restart th ee ng ine.
The display message disappears.
u SRS Malfunction Ser ‐
vic eR equired The restrain ts ystem is malfunctioning .T he u warning lamp also
lights up in th ei nstrumen tc luster.
G WARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th ee vent of an accident, may no tbet ri ggered .
There is an increased ris kofi njury.X
Visit aq ualified specialist workshop immediately.
Fo rf urther information about th er estrain ts ystem, see ( Y
page 40) .
u Front Lef tM alfunc‐
tio nS ervic e
Required or Front
Right Malfunction
Servic eR equired The restrain ts ystem is malfunctioning at th ef ront on th el ef torr ight .
The u warning lamp also lights up in th ei nstrumen tc luster.
G WARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th ee vent of an accident, may no tbet ri ggered .
There is an increased ris kofi njury.X
Visit aq ualified specialist workshop immediately.198
Display messages
On-boar dc omputer an dd isplays

Display messages
Possible causes/consequences and P Solutions
u Rea rL ef tM alfunc‐
tio nS ervic e
Required or Rea r
Right Malfunction
Servic eR equired The rear left-han dorr ight-hand restrain ts ystem is malfunctioning .
The u warning lamp also lights up in th ei nstrumen tc luster.
G WARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th ee vent of an accident, may no tbet ri ggered .
There is an increased ris kofi njury.X
Visit aq ualified specialist workshop immediately.
u Lef tS id eC urtai n
Airbag Malfunction
Servic eR equired or
Right Sid eC urtai n
Airbag Malfunction
Servic eR equired The left-han dorr ight-hand window curtai na ir bag is malfunctioning .
The u warning lamp also lights up in th ei nstrumen tc luster.
G WARNIN G
The lef torr ight window curtai na ir bag may either be triggered unin-
tentionally or, in th ee vent of an accident, may no tbet ri ggered .
There is an increased ris kofi njury.X
Visit aq ualified specialist workshop immediately. Display messages 19 9
On-boar dc omputer an dd isplays Z

Tires Display messages
Possible causes/consequence sa nd P Solutions
Check Tire Pressure
Soon Canad ao nly:
The tire pressure loss warning system ha sd et ecte das ig nificant loss
in pressure.
Aw ar ning tone also sounds.
Possibl ec auses: R
yo uh av ec hange dt he positions of the wheels and tire sori nstalled
new wheels and tires R
the tire pressure in one or mor et ire sh as dropped
G WARNING
Tire pressures tha ta re too lo wp os et he following hazards:R
the ym ay burst, especially as the load and vehicl es peed increase.R
the ym ay wear excessivel ya nd/or unevenly, which ma yg reatly
impai rt ire traction. R
the drivin gc haracteristics, as well as steerin ga nd braking ,m ay be
greatl yi mpaired.
There is ar is kofana ccident.X
Stop the vehicl ew it hou tm ak ing any sudden steerin gorb raking
maneuvers. Pa ya ttentio ntot he traffi cc onditions as yo udos o.X
Secure the vehicl ea gain st rolling away ( Y
page 141).X
Check the tire sa nd ,ifn ecessary ,f ollo wt he instructions for af lat
tire ( Y
page 271). X
Check the tire pressures and ,ifn ecessary ,c orrect the tire pressure.X
Restart the tire pressure loss warning system when the tire pres-
sure is correct ( Y
page 294).
Check Tire Pressure
The nR estar tR un
Fla tI ndicator Canad ao nly:
The tire pressure loss warning system generated ad isplay message
and ha sn ot been restarted since. X
Set the correct tire pressure in al lf ou rt ires.X
Restart the tire pressure loss warning system ( Y
page 294).
Run Fla tI ndicator
Inoperative Canad ao nly:
The tire pressure loss warning system is faulty. X
Visi taq uali fied specialis tw or kshop.
Please Correct Tire
Pressure USA only:
The tire pressure is too lo winatl east one of the tires, or the tire
pressure differenc eb et ween the wheels is too great.X
Check the tire pressures at the next opportunity ( Y
page 294).X
If necessary ,c orrect the tire pressure.X
Restart the tire pressure monitor ( Y
page 297).Displa ym essages 21 1
On-boar dc omputer an dd isplays Z

Warning and indicator lamps in the instrument cluster
General notes Some systems carry out as elf-diagnosis when the ignition is switched on. Therefore, some indicator
and warning lamps may light up or flas ht emporarily .T his behavior is non-critical.
These indicator and warning lamps only indicate am alfunction if they light up or flas ha fter starting
the engine or whilst driving.
Safety
Seat belts Warning/
indicator
lamp Q Signal type
Possibl ec auses/consequence sa nd P Solutions

Safety systems Warning/
indicator
lamp Q Signal type
Possible causes/consequences and P Solutions
'M
Q ' (USA only), M (Canada only): the red brake system warning lamp is lit
while the engine is running. Aw arning tone also sounds.
G WARNING
The brake boosting effect is malfunctioning and the braking characteristics may be
affected.
There is ar isk of an accident.X
Pull over and stop the vehicle safely as soon as possible, paying attention to road
and traffic conditions. Do not continue driving under any circumstances. X
Secure the vehicle against rolling away ( Y
page 141).X
Consult aq ualified specialist workshop.X
Observe the additional display messages in the multifunction display.
'M
Q ' (USA only), M (Canada only): the red brake system warning lamp is lit
while the engine is running. Aw arning tone also sounds.
There is not enough brake fluid in the brake fluid reservoir.
G WARNING
The braking effect may be impaired.
There is ar isk of an accident.X
Pull over and stop the vehicle safely as soon as possible, paying attention to road
and traffic conditions. Do not continue driving under any circumstances. X
Secure the vehicle against rolling away ( Y
page 141).X
Do not add brake fluid. Adding more will not correct the malfunction. X
Consult aq ualified specialist workshop.X
Observe the additional display messages in the multifunction display.Warning and indicator lamp sint he instrument cluster 219
On-board computer and displays Z

Warning/
indicator
lamp Q Signal type
Possibl ec auses/consequences and P Solutions
%
Q The yellow ABS warning lamp is lit while the engine is running.
ABS (Anti-lock Braking System) is deactivated due to am alfunction. Therefore,
BAS (Brake Assist), Active Brake Assist, ESP ®
(Electronic Stability Program), the
HOLD function and hil ls tart assist, for example, are als od eactivated.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions listed
above. The wheels coul dt herefore lock if you brake hard ,f or example.
The steerability and braking characteristics may be severely affected. The braking
distance in an emergency braking situation can increase.
If ESP ®
is not operational ,E SP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident. X
Observe the additiona ld isplay messages in the multifunction display.X
Drive on carefully. X
Visi taq ualified specialist worksho pi mmediately.
If the ABS control unit is faulty, there is als oap ossibility that other systems ,s uch
as the navigation system or the automatic transmission, wil ln ot be available.
%
Q The yellow ABS warning lamp is lit while the engine is running.
ABS is temporarily unavailable .T herefore, BAS, Active Brake Assist, ESP ®
,E BD
(electronic brake force distribution), the HOLD function and hil ls tart assist, for
example, are als od eactivated.
Possible causes are: R
Self-diagnosi sisn ot yet complete.R
The on-board voltag em ay be insufficient.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions listed
above. The front and rear wheels coul dt herefore lock if you brake hard ,f or exam-
ple.
The steerability and braking characteristics may be severely affected. The braking
distance in an emergency braking situation can increase.
If ESP ®
is not operational ,E SP ®
is unable to stabilize the vehicle.
There is ar isk of an accident.X
Carefully drive as uitable distance, making slight steering movements at as peed
above 12 mph (20 km/h).
The functions mentioned above are available again when the warning lamp goes
out.
If the warning lamp is still on: X
Observe the additiona ld isplay messages in the multifunction display.X
Drive on carefully. X
Visi taq ualified specialist worksho pi mmediately.220
Warning and indicator lamps in the instrument cluster
On-board computer and displays

Warning/
indicator
lamp Q Signal type
Possibl ec auses/consequences and P Solutions
%
Q The yellow ABS warning lamp is lit while the engine is running. Aw arning tone
als os ounds.
EBD is malfunctioning. Therefore, ABS, BAS, Active Brake Assist, ESP ®
,t he HOLD
function and hil ls tart assist, for example, are not available either.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions listed
above. The front and rear wheels coul dt herefore lock if you brake hard ,f or exam-
ple.
The steerability and braking characteristics may be severely affected. The braking
distance in an emergency braking situation can increase.
If ESP ®
is not operational ,E SP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident. X
Observe the additiona ld isplay messages in the multifunction display.X
Drive on carefully. X
Visi taq ualified specialist worksho pi mmediately.
%

Warning/
indicator
lamp Q Signal type
Possibl ec auses/consequences and P Solutions