Page 328 of 462

Safety systems
ProblemPossible causes/consequences andMSolutions
$(USA only)
The red brake system
warning lamp comes on
while the engine is run-
ning.
A warning tone also
sounds.GWARNING
The brake boosting effect is malfunctioning and the braking char-
acteristics may be affected.
There is a risk of an accident.
XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.
XSecure the vehicle against rolling away (Ypage 189).
XConsult a qualified specialist workshop.
XObserve the additional display messages in the multifunction
display.
There is not enough brake fluid in the brake fluid reservoir.
GWARNING
The braking effect may be impaired.
There is a risk of an accident.
XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.
XSecure the vehicle against rolling away (Ypage 189).
XDo not add brake fluid. Adding more will not remedy the mal-
function.
XConsult a qualified specialist workshop.
XObserve the additional display messages in the multifunction
display.
326Warning and indicator lamps in the instrument cluster
On-board computer and displays
Page 329 of 462

ProblemPossible causes/consequences andMSolutions
!
The yellow ABS warning
lamp is lit while the
engine is running.ABS (Anti-lock Braking System) is deactivated due to a malfunc-
tion. Therefore, BAS (Brake Assist), BAS PLUS, COLLISION PRE-
VENTION ASSIST, ESP
®(Electronic Stability Program), ESP®trailer
stabilization, PRE‑SAFE®, PRE‑SAFE®Brake, HOLD function, hill
start assist, Crosswind Assist, STEER CONTROL, Active Lane
Keeping Assist and Active Blind Spot Assist are also deactivated.
In addition, the ÷andå warning lamps may light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
GWARNING
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 affec-
ted. 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.
XObserve the additional display messages in the multifunction
display.
XDrive on carefully.
XVisit 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 trans-
mission, will not be available.
Warning and indicator lamps in the instrument cluster327
On-board computer and displays
Z
Page 330 of 462

ProblemPossible causes/consequences andMSolutions
!
The yellow ABS warning
lamp is lit while the
engine is running.ABS is temporarily unavailable. Therefore, BAS, BAS PLUS, COL-
LISION PREVENTION ASSIST, ESP®, ESP®trailer stabilization, EBD
(electronic brake force distribution), PRE‑SAFE®,
PRE‑SAFE®Brake, the HOLD function, hill start assist, Crosswind
Assist, STEER CONTROL, Active Lane Keeping Assist and Active
Blind Spot Assist, for example, are also deactivated.
In addition, the ÷andå warning lamps may light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
Possible causes are:
RSelf-diagnosis is not yet complete.
Rthe on-board voltage may be insufficient.
GWARNING
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 affec-
ted. 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.
XCarefully drive a suitable distance, making slight steering move-
ments 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:
XObserve the additional display messages in the multifunction
display.
XDrive on carefully.
XVisit a qualified specialist workshop.
328Warning and indicator lamps in the instrument cluster
On-board computer and displays
Page 331 of 462

ProblemPossible causes/consequences andMSolutions
!
The yellow ABS warning
lamp is lit while the
engine is running.
A warning tone also
sounds.EBD is not available due to a malfunction. Therefore ABS, BAS, BAS
PLUS, ESP®, ESP®trailer stabilization, PRE‑SAFE®,
PRE‑SAFE®Brake, COLLISION PREVENTION ASSIST, HOLD func-
tion, hill start assist, Crosswind Assist, STEER CONTROL, Active
Lane Keeping Assist and Active Blind Spot Assist are also unavail- able.
In addition, the ÷andå warning lamps may light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
GWARNING
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 affec-
ted. 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.
XObserve the additional display messages in the multifunction
display.
XDrive on carefully.
XVisit a qualified specialist workshop.
Warning and indicator lamps in the instrument cluster329
On-board computer and displays
Z
Page 332 of 462

ProblemPossible causes/consequences andMSolutions
$(USA only)
֌!
The red brake warning
lamp, the yellow ESP
®
and ESP®OFF warning
lamp and the yellow
ABS warning lamp are
lit while the engine is
running.
ABS and ESP®are malfunctioning. Therefore BAS, BAS PLUS,
COLLISION PREVENTION ASSIST, ESP®trailer stabilization,
PRE‑SAFE®, PRE ‑SAFE®Brake, HOLD function, hill start assist,
Crosswind Assist, STEER CONTROL, Active Lane Keeping Assist
and Active Blind Spot Assist are also unavailable.
ATTENTION ASSIST is deactivated.
GWARNING
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 affec-
ted. 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.
XObserve the additional display messages in the multifunction
display.
XDrive on carefully.
XVisit a qualified specialist workshop.
÷
The yellow ESP
®warn-
ing 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.
XWhen pulling away, only depress the accelerator pedal as far as
necessary.
XEase off the accelerator pedal while the vehicle is in motion.
XAdapt your driving style to suit the road and weather conditions.
XDo not deactivate ESP®.
In rare cases (
Ypage 74), it may be best to deactivate ESP®.
Observe the important safety notes on ESP
®(Ypage 73).
330Warning and indicator lamps in the instrument cluster
On-board computer and displays
Page 333 of 462

ProblemPossible causes/consequences andMSolutions
å
The yellow ESP
®OFF
warning lamp is lit while
the engine is running.
ESP®is deactivated.
GWARNING
If ESP®is switched off, ESP®is unable to stabilize the vehicle.
Further driving systems or driving safety systems are thus restric-
ted, e.g. Active Blind Spot Assist. The system does not perform
course-correcting brake applications.
There is an increased risk of skidding and an accident.
XReactivate ESP®.
In rare cases (
Ypage 74), it may be best to deactivate ESP®.
Observe the important safety notes on ESP
®(Ypage 73).
XAdapt your driving style to suit the road and weather conditions.
If ESP
®cannot be activated:
XHave ESP®checked at a qualified specialist workshop.
֌
The yellow ESP
®and
ESP®OFF warning
lamps are lit while the
engine is running.
ESP®, BAS, BAS PLUS, COLLISION PREVENTION ASSIST, ESP®
trailer stabilization, PRE‑ SAFE®, PRE‑SAFE®Brake, the HOLD func-
tion, hill start assist, Crosswind Assist, STEER CONTROL, Active
Lane Keeping Assist and Active Blind Spot Assist are not available
due to a malfunction.
ATTENTION ASSIST is deactivated.
GWARNING
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.
XObserve the additional display messages in the multifunction
display.
XDrive on carefully.
XVisit a qualified specialist workshop.
Warning and indicator lamps in the instrument cluster331
On-board computer and displays
Z
Page 334 of 462

ProblemPossible causes/consequences andMSolutions
֌
The yellow ESP
®and
ESP®OFF warning
lamps are lit while the
engine is running.
ESP®, BAS, PRE-SAFE®, the HOLD function, hill start assist, Cross-
wind Assist and ESP®trailer stabilization are temporarily unavail-
able.
COLLISION PREVENTION ASSIST, BAS PLUS and
PRE ‑SAFE
®Brake may also have failed.
ATTENTION ASSIST is deactivated.
Self-diagnosis is not yet complete.
GWARNING
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.
XCarefully drive a suitable distance, making slight steering move-
ments 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:
XObserve the additional display messages in the multifunction
display.
XDrive on carefully.
XVisit a qualified specialist workshop.
332Warning and indicator lamps in the instrument cluster
On-board computer and displays
Page 335 of 462
ProblemPossible causes/consequences andMSolutions
F(USA only)
The red electric parking
brake indicator lamp
flashes or lights up
and/or
!
the yellow warning
lamp for the electric
parking brake lights up.XObserve the additional display messages in the multifunction
display.
6
The red restraint sys-
tem warning lamp is lit
while the engine is run-
ning.The restraint system is faulty.
GWARNING
The air bags or Emergency Tensioning Devices may either be trig-
gered unintentionally or, in the event of an accident, may not be
triggered.
There is an increased risk of injury.
XObserve the additional display messages in the multifunction
display.
XDrive on carefully.
XHave the restraint system checked immediately at a qualified
specialist workshop.
For further information about the restraint system, see
(
Ypage 44).
Warning and indicator lamps in the instrument cluster333
On-board computer and displays
Z