Page 305 of 434

Safety systems
Warning/
indicator
lamp 0051 0051
Signal type
Possible causes/consequences and 0050
0050Solutions 0027004D
0051
0027 (USA only), 004D(Canada only): the red 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 190).
X Consult a qualified specialist workshop.
X Observe the additional display messages in the multifunction display. 0027004D
0051
0027 (USA only), 004D(Canada only): the red 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 190).
X Do not add brake fluid. Adding more 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
303On-board computer and displays Z
Page 306 of 434

Warning/
indicator
lamp 0051
0051 Signal type
Possible causes/consequences and 0050
0050 Solutions 0025
0051
The yellow ABS warning lamp is lit while the engine is running.
ABS (Anti-lock Braking System) is deactivated due to a malfunction. Therefore,
BAS (Brake Assist), BAS PLUS, COLLISION PREVENTION ASSIST, ESP ®
(Electronic Stability Program), PRE-SAFE ®
, PRE-SAFE ®
PLUS, PRE-SAFE ®
Brake, the HOLD function, hill start assist and crosswind driving assistance,
for example, are also deactivated.
ATTENTION ASSIST is 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. 304
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Page 307 of 434

Warning/
indicator
lamp 0051 0051
Signal type
Possible causes/consequences and 0050
0050Solutions 0025
0051
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,
COLLISION PREVENTION ASSIST, ESP ®
, PRE-SAFE ®
, PRE-SAFE ®
PLUS, PRE-
SAFE ®
Brake, the HOLD function, hill start assist and crosswind driving
assistance, for example, are also unavailable.
ATTENTION ASSIST is deactivated.
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. 0027004D
00E50025
0051
0027 (USA only), 004D(Canada only): the red brake warning lamp, the
yellow ESP ®
warning lamp and the yellow ABS warning lamp are lit while the
engine is running.
ABS and ESP ®
are not available due to a malfunction. Therefore, BAS, BAS
PLUS, COLLISION PREVENTION ASSIST, EBD, PRE-SAFE ®
, PRE-SAFE ®
PLUS,
PRE-SAFE ®
Brake, the HOLD function, hill start assist and crosswind driving
assistance, for example, are also unavailable.
ATTENTION ASSIST is deactivated.
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. Warning and indicator lamps in the instrument cluster
305On-board computer and displays Z
Page 308 of 434

Warning/
indicator
lamp 0051
0051 Signal type
Possible causes/consequences and 0050
0050 Solutions 00E5
0051
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 ®
.
In rare cases (Y page 76), it may be best to deactivate ESP ®
. 00E5
0051
The yellow ESP ®
warning lamp is lit while the engine is running.
ESP ®
, BAS, BAS PLUS, COLLISION PREVENTION ASSIST, PRE-SAFE ®
,
PRE-SAFE ®
PLUS, PRE-SAFE ®
Brake, the HOLD function, hill start assist and
crosswind driving assistance are not available due to a malfunction.
ATTENTION ASSIST is deactivated.
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. 00BB
0051
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 ®
.
In rare cases (Y page 76), it may be best to deactivate ESP ®
.
X Adapt your driving style to suit the road and weather conditions.
If ESP ®
cannot be activated:
X Drive on carefully.
X Have ESP ®
checked at a qualified specialist workshop. 306
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Page 309 of 434

Warning/
indicator
lamp 0051 0051
Signal type
Possible causes/consequences and 0050
0050Solutions 00490024
0051
0049 (USA only), 0024(Canada only): the red indicator lamp for the electric
parking brake flashes or is lit and/or the yellow warning lamp for the electric
parking brake is lit.
X Observe the additional display messages in the multifunction display. 0075
0051
The red SRS warning lamp is lit while the engine is running.
There is a malfunction in the SRS (Supplemental Restraint System).
G WARNING
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in the event of an accident, may not be triggered.
There is an increased risk of injury.
X Observe the additional display messages in the multifunction display.
X Drive on carefully.
X Have SRS checked at a qualified specialist workshop immediately.
For further information about SRS, see (Y page 45).Warning and indicator lamps in the instrument cluster
307On-board computer and displays Z
Page 310 of 434

Engine
Warning/
indicator
lamp 0051 0051
Signal type
Possible causes/consequences and 0050
0050 Solutions 00B9
0051
The yellow Check Engine warning lamp lights up while the engine is running.
There may be a malfunction, for example:
R in the engine management
R in the fuel injection system
R in the exhaust system
R in the ignition system (for vehicles with gasoline engines)
R in the fuel system
The emission limit values may be exceeded and the engine may be in
emergency mode.
X Have the vehicle checked as soon as possible at a qualified specialist
workshop.
i In some states, you must immediately visit a qualified specialist workshop
as soon as the yellow Check Engine warning lamp lights up. This is due to
the legal requirements in effect in these states. If in doubt, check whether
such legal regulations apply in the state in which you are currently driving. 00B6
0051
The yellow reserve fuel warning lamp lights up while the engine is running.
The fuel level has dropped into the reserve range.
X Refuel at the nearest gas station. 00B6
0051
The yellow reserve fuel warning lamp flashes while the vehicle is in motion.
In addition, the 00B9Check Engine warning lamp may light up.
The fuel system pressure is too low. The fuel filler cap is not closed correctly
or the fuel system is leaking.
X Check that the fuel filler cap is correctly closed.
X If the fuel filler cap is not correctly closed: close the fuel filler cap.
X If the fuel filler cap is closed: visit a qualified specialist workshop.308
Warning and indicator lamps in the instrument clusterOn-board computer and displays
Page 311 of 434
Warning/
indicator
lamp 0051 0051
Signal type
Possible causes/consequences and 0050
0050Solutions 00AC
0051
The red coolant warning lamp lights up while the engine is running and the
coolant temperature gauge is at the start of the bar display.
The temperature sensor for the coolant temperature gauge is defective.
The coolant temperature is no longer being monitored. There is a risk of engine
damage if the coolant temperature is too high.
X Pull over and stop the vehicle safely and switch off the engine, paying
attention to road and traffic conditions. Do not continue driving under any
circumstances.
X Secure the vehicle against rolling away (Y page 190).
X Consult a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
309On-board computer and displays Z
Page 312 of 434

Warning/
indicator
lamp 0051
0051 Signal type
Possible causes/consequences and 0050
0050 Solutions 00AC
0051
The red coolant warning lamp comes on while the engine is running.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator may be blocked
or the electric engine radiator fan may be malfunctioning.
The coolant is too hot and the engine is no longer being cooled sufficiently.
X Observe the additional display messages in the multifunction display.
X Pull over and stop the vehicle safely and switch off the engine, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 190).
X Leave the vehicle and keep a safe distance from the vehicle until the engine
has cooled down.
X Check the coolant level and add coolant, observing the warning notes
(Y page 351).
X If you need to add coolant more often than usual, have the engine coolant
system checked.
X Make sure that the air supply to the engine radiator is not blocked, e.g. by
snow, slush or ice.
X Do not start the engine again until the coolant temperature is below
248 ‡ (120 †). Otherwise, the engine could be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in mountainous
terrain, and stop-and-go traffic. 00AC
0051
The red coolant warning lamp comes on while the engine is running. A
warning tone also sounds.
The coolant temperature has exceeded 248 ‡ (120 †). The airflow to the
engine radiator may be blocked or the coolant level may be too low.
G WARNING
The engine is not being cooled sufficiently and may be damaged.
Do not drive when your engine is overheated. This can cause some fluids which
may have leaked into the engine compartment to catch fire.
Steam from the overheated engine can also cause serious burns which can
occur just by opening the hood.
There is a risk of injury.
X Observe the additional display messages in the multifunction display.
X Pull over and stop the vehicle safely and switch off the engine, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 190).310
Warning and indicator lamps in the instrument clusterOn-board computer and displays