Page 249 of 364

SmartKey
Display messages Possible causes/consequences and
M SolutionsÂ
Key Does Not
Belong to Vehicle You have put the wrong SmartKey in the ignition lock.
X
Use the correct SmartKey. Â
Take
Your Key from
Ignition The SmartKey is in the ignition lock.
X
Remove the SmartKey. Â
Obtain a New Key The SmartKey needs to be replaced.
X
Visit a qualified specialist workshop. Warning and indicator lamps in the
instrument cluster
Overview of warning and indicator
lamps
L Low-beam
headlamps
(Y page 99)
#! Turn signals (Y page 103)
K High-beam headlamps
(Y page 103)
N Fog lamps (Y page 101)
R Rear fog lamp (Y page 101)
ü Seat belts (Y page 248)
$ (USA) Brakes (Y page 249)
J (Canada) Brakes (yellow) (Y page 249)
! ABS (Y page 250)
÷ ESP®
(Y page 252)
å ESP®
OFF (Y page 252)
6 SRS (Y page 255)
; Check Engine (Y page 256)
8 Reserve fuel (Y page 256)
? Coolant (Y page 256)
· Distance warning signal
(Y page 258)
h Tire pressure monitor
(Y page 259) Warning and indicator lamps in the instrument cluster
247
On-board computer and displays Z
Page 250 of 364

Safety
Seat belts Problem Possible causes/consequences and
M Solutionsü
After starting the
engine, the red seat
belt
warning lamp lights
up for six seconds. The seat belt warning lamp reminds the driver and front passenger
to fasten their seat belts.
X
Fasten your seat belt ( Y page 50).ü
After starting the
engine, the red seat
belt
warning lamp lights
up. In addition, a
warning tone sounds
for up to six seconds. The driver's seat belt is not fastened.
X
Fasten your seat belt ( Y page 50).
The warning tone ceases. ü
The red seat belt
warning lamp lights up
after the engine starts,
as soon as the driver's
or the front-passenger
door is closed.
The driver or front passenger has not fastened their seat belt.
X
Fasten your seat belt ( Y page 50).
The warning lamp goes out. There are objects on the front-passenger seat.
X
Remove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out. ü
The red seat belt
warning lamp flashes
and an intermittent
audible warning
sounds.
The driver or front passenger has not fastened their seat belt. In
addition,
you are driving faster than 15 mph (25 km/h) or you have
briefly driven faster than 15 mph (25 km/h).
X Fasten your seat belt ( Y page 50).
The warning lamp goes out and the intermittent warning tone
ceases. There are objects on the front-passenger seat. In addition, you are
driving faster than 15 mph (25 km/h
) or you have briefly driven
faster than 15 mph (25 km/h).
X Remove the objects from the front-passenger seat and stow
them in a secure place.
The warning lamp goes out and the intermittent warning tone
ceases.248
Warning and indicator lamps in the instrument cluster
On-board computer and displays
Page 251 of 364

Safety systems
Problem Possible causes/consequences and
M Solutions$ (USA only)
J (Canada only)
USA only:
the red
brake system warning
lamp is lit while the
engine is running. A
warning tone also
sounds.
Canada only: the
yellow brake system
warning
lamp is lit while
the engine is running. A
warning tone also
sounds. G
WARNING
The brake boosting effect is malfunctioning and the braking
characteristics may be affected.
There is a risk 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 156).
X Consult a qualified specialist workshop.
X Observe the additional display messages in the multifunction
display. $ (USA only)
J (Canada only)
USA only:
the red
brake system warning
lamp is lit while the
engine is running. A
warning tone also
sounds.
Canada only: the
yellow brake system
warning
lamp is lit while
the engine is running. A
warning tone also
sounds. There is not enough brake fluid in the brake fluid reservoir.
G WARNING
The braking effect may be impaired.
There is a risk 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 156).
X Do not add brake fluid. Topping up will not remedy the
malfunction.
X Consult a qualified specialist workshop.
X Observe the additional display messages in the multifunction
display. Warning and indicator lamps in the instrument cluster
249
On-board computer and displays Z
Page 252 of 364

Problem Possible causes/consequences and
M Solutions!
The
yellow ABS warning
lamp is lit while the
engine is running. ABS (Anti-lock Brake System) is deactivated due to a malfunction.
BAS
(Brake Assist), ESP ®
(Electronic Stability Program), the HOLD
function, hill start assist, the adaptive brake lights and ESP ®
trailer
stabilization, for example, are therefore also deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for 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, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic
transmission, will not be available. 250
Warning and indicator lamps in the instrument cluster
On-board computer and displays
Page 253 of 364

Problem Possible causes/consequences and
M Solutions!
The
yellow ABS warning
lamp is lit while the
engine is running. ABS is temporarily unavailable. BAS, ESP
®
, EBD (electronic brake
force distribution), the HOLD function, hill start assist, ESP ®
trailer
stabilization and the adaptive brake lights, for example, are
therefore also deactivated.
Possible causes are:
R Self-diagnosis is not yet complete.
R The on-board voltage may be insufficient.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear wheels could therefore
lock if you brake hard, for 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, ESP ®
is unable to stabilize the vehicle.
There is a risk of an accident.
X Carefully drive a suitable distance making slight steering
movements at a speed 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 additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
251
On-board computer and displays Z
Page 254 of 364

Problem Possible causes/consequences and
M Solutions!
The
yellow ABS warning
lamp is lit while the
engine is running. A
warning tone also
sounds. EBD is malfunctioning. Therefore, ABS, BAS, ESP
®
, the HOLD
function, hill start assist, the adaptive brake lights and ESP ®
trailer
stabilization are also not available, for example.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear wheels could therefore
lock if you brake hard, for 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, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. !
The
yellow ABS warning
lamp is lit while the
engine is running. You have engaged the differential locks. ABS is deactivated.
X
Disengage the differential locks.
Subsequently ABS is reactivated. $ (USA only)
J (Canada only)
֌!
The yellow brake
warning lamp, the
yellow ESP
®
and
ESP ®
OFF warning
lamps and the yellow
ABS warning lamp are
lit while the engine is
running. ABS and ESP
®
are malfunctioning. Therefore, BAS, EBD, the HOLD
function, hill start assist, the adaptive brake lights and ESP ®
trailer
stabilization, for example, are also not available.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear wheels could therefore
lock if you brake hard, for 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, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop.252
Warning and indicator lamps in the instrument cluster
On-board computer and displays
Page 255 of 364

Problem Possible causes/consequences and
M Solutions÷
The yellow ESP
®
warning lamp flashes
while the vehicle is in
motion. ESP
®
or traction control has intervened because there is a risk of
skidding or at least one wheel has started to spin.
Cruise control or DISTRONIC PLUS is deactivated.
X When pulling away, only depress the accelerator pedal as far as
necessary.
X Ease off the accelerator pedal while the vehicle is in motion.
X Adapt your driving style to suit the road and weather conditions.
X Do not deactivate ESP ®
.
For exceptions, see: ( Y page 62).å
The yellow ESP
®
OFF
warning
lamp is lit while
the engine is running. ESP
®
is deactivated.
G WARNING
If ESP ®
is switched off, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Reactivate ESP ®
.
For exceptions, see: ( Y page 62).
X Adapt your driving style to suit the road and weather conditions.
If ESP ®
cannot be activated:
X Have ESP ®
checked at a qualified specialist workshop. ֌
The yellow ESP
®
and
ESP ®
OFF warning
lamps are lit while the
engine is running. ESP
®
,
BAS, the HOLD function, hill start assist, the adaptive brake
lights and ESP ®
trailer stabilization are not available due to a
malfunction.
G WARNING
The brake system continues to function normally, but without the
functions listed above.
The braking distance in an emergency braking situation can thus
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
253
On-board computer and displays Z
Page 256 of 364

Problem Possible causes/consequences and
M Solutions֌
The yellow ESP
®
and
ESP ®
OFF warning
lamps are lit while the
engine is running. ESP
®
, BAS, the HOLD function, hill start assist and ESP ®
trailer
stabilization are temporarily unavailable.
BAS and the adaptive brake lights may also have failed.
Self-diagnosis is not yet complete.
G WARNING
The brake system continues to function normally, but without the
functions listed above.
The braking distance in an emergency braking situation can thus
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Carefully drive a suitable distance making slight steering
movements at a speed 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 additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. å
The yellow ESP
®
OFF
warning
lamp is lit while
the engine is running. You have engaged the differential locks. ABS, ESP
®
, 4ETS and BAS
have been deactivated.
X Disengage the differential locks.
ESP ®
, 4ETS and BAS are subsequently reactivated.
X Observe the additional display messages in the multifunction
display.254
Warning and indicator lamps in the instrument cluster
On-board computer and displays