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Troubleshooting
245Problem Possible cause/consequence Suggested solutions
v
The yellow ESP ®
warning
lamp flashes while the
vehicle is in motion. G
Risk of accident
ESP ®
or traction control has
intervened because at least one
wheel has started to spin.
Cruise control or Distronic* is
deactivated. X
Only depress the accelerator pedal as far as necessary when pull-
ing away.
X Release the accelerator pedal while you are driving.
X Adapt your driving style to suit the road and weather conditions.
X Do not deactivate ESP ®
. Exceptions: (Y page 59).3
The red brake system
warning lamp comes on
while you are driving. You
will also hear a warning
tone. You are driving with the parking
brake applied. X
Release the parking brake.
The warning lamp goes out and the warning tone ceases. 3
The red brake system
warning lamp comes on
while the engine is run-
ning. You will also hear a
warning tone. G
Risk of accident
There is insufficient brake fluid in
the fluid reservoir. X
Do not continue driving under any circumstances.
X Consult a qualified specialist workshop immediately.
X Observe the additional messages in the multi-function display
(Y page 219).
X Under no circumstances should you top up the brake fluid. This will
not rectify the fault. l
The red distance warning
lamp* lights up while the
vehicle is in motion. G
Risk of accident
The distance to the vehicle in
front is too short for the speed
selected. X
Increase the distance. Practical advice
* optional
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Troubleshooting
246 Problem Possible cause/consequence Suggested solutions
l
The red distance warning
lamp* lights up while the
vehicle is in motion. You
will also hear a warning
tone. G
Risk of accident
You are approaching a vehicle in
front at too great a speed or Dis-
tronic*
has detected a stationary
obstacle in your line of travel. X
Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to brake
or take evasive action. D
The red coolant warning
lamp comes on while the
engine is running. There is insufficient coolant in the
expansion tank.
The coolant is too hot and the
engine is no longer being cooled
sufficiently. X
Stop the vehicle as soon as possible. Pay attention to the traffic
conditions as you do so.
X Allow the engine and coolant to cool.
X Check the coolant level. Observe the warning notes
(Y page 196). Top up the coolant if necessary.
X Have the coolant system checked at a qualified specialist work-
shop if the coolant needs topping up more often than usual. D
The red coolant warning
lamp comes on while the
engine is running. If the coolant level is correct, the
radiator fan may be faulty.
The coolant is too hot and the
engine is no longer being cooled
sufficiently. X
If the coolant temperature is less than 120†, you can continue
driving to the nearest qualified specialist workshop.
X In doing so, avoid heavy loads on the engine (e.g. driving in moun-
tainous terrain) and stop-and-go driving. Practical advice
* optional
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Troubleshooting
248 Problem Possible cause/consequence Suggested solutions
±
The yellow engine diagnos-
tics warning lamp comes
on
while the engine is run-
ning. There may be a malfunction:
R
in the fuel injection system
R in the exhaust system
R in
the ignition system (on vehi-
cles with a petrol engine)
The emission limit values may be
exceeded and the engine may be
running in emergency mode. X
Have the vehicle checked as soon as possible at a qualified spe-
cialist workshop. H
The yellow tyre pressure
monitor* warning lamp is
on. G
Risk of accident
The tyre pressure monitor* has
detected a sudden or significant
pressure loss in at least one of
the tyres. X
Stop the vehicle without making any sudden steering or braking
manoeuvres. Pay attention to the traffic conditions as you do so.
X Observe the additional messages in the multi-function display
(Y page 219).
The warning light will go out after the flat tyre has been changed
and you have been driving for a few minutes. 1
The red SRS warning lamp
is lit while the engine is
running. G
Risk of injury
The restraint systems are faulty.
The airbags or belt tensioners
may either be triggered uninten-
tionally
or, in the event of an acci-
dent, not be triggered at all. X
Visit a qualified specialist workshop immediately. Practical advice
* optional
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Troubleshooting
249Problem Possible cause/consequence Suggested solutions
<
The red seat belt warning
lamp lights up for 6 sec-
onds after the engine
starts up 28
. The seat belt warning lamp
reminds the driver and front
passenger to fasten their seat
belts. X
Fasten your seat belt ( Y page 88).<
After the engine starts you
will
hear a warning tone for
up to 6 seconds 28
. G
Risk of injury
The driver's seat belt is not fas-
tened. X
Fasten your seat belt ( Y page 88).
The warning tone ceases. <
The red seat belt warning
lamp lights up after start-
ing the engine, as soon as
the driver's door or the
front-passenger door is
closed. G
Risk of injury
The driver or front passenger has
not fastened their seat belt. X
Fasten your seat belt ( Y page 88).
The warning lamp goes out. G
Risk of injury
There are objects on the front-
passenger seat. X
Remove the objects from the front-passenger seat and stow them
safely.
The warning lamp goes out. 28
Only for certain countries. Practical advice
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Troubleshooting
251Warning tones
Problem Possible cause/consequence Suggested solutions
The anti-theft alarm system* is
suddenly triggered. You have opened the vehicle
using
the emergency key element
without deactivating the anti-
theft alarm system* first. X
Switch off the alarm (Y page 61). You hear a warning tone. A message appears in the multi-
function display. X
See the explanations for the display message ( Y page 219).You hear a warning tone. You are driving with the parking
brake applied. X
Release the parking brake. You hear a warning tone. You have opened the driver's
door and forgotten to switch off
the lights. X
Turn the light switch to M or U.You hear a warning tone.
G
Risk of injury
The driver or front passenger has
not fastened their seat belt. X
Fasten your seat belt ( Y page 88).You hear a continuous tone. You have switched off the engine
and opened the bonnet or the
driver's
door with Hold activated. X
Deactivate HOLD (Y page 145). Practical advice
* optional
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Troubleshooting
256 Problem Possible cause/consequence Suggested solutions
Vehicles with a petrol engine:
The engine is not running
smoothly and is misfiring. The engine electronics or a
mechanical component of the
engine control unit have been
damaged. X
Only depress the accelerator pedal slightly.
X Have the cause rectified immediately at a qualified specialist work-
shop.
Otherwise,
non-combusted fuel may get into the catalytic converter
and damage it. A coolant temperature of over
120 °C is displayed. The coolant
warning
lamp may also be on and
a warning tone may sound
(Y page 110). The coolant level is too low. The
coolant
is too hot and the engine
is no longer being cooled suffi-
ciently. X
Stop as soon as possible and allow the engine and the coolant to
cool down.
X Check the coolant level (Y page 196). Observe the warning notes
as you do so and top up the coolant if necessary. If the coolant level is correct, the
radiator fan may be faulty. The
coolant
is too hot and the engine
is no longer being cooled suffi-
ciently. X
If the coolant temperature is less than 120°C, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. when driving on
mountain roads and stop/start driving. Practical advice
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Troubleshooting
258 Parktronic*
Problem Possible cause/consequence Suggested solutions
Only the red segments in the
Parktronic
warning display are lit.
You also hear a warning tone for
approximately two seconds.
Parktronic is deactivated after
approximately 20 seconds and
the indicator lamp in the Park-
tronic button lights up. Parktronic has malfunctioned
and has switched itself off. X
If problems persist, have Parktronic checked at a qualified spe-
cialist workshop. Only the red segments in the
Parktronic
warning display are lit.
Parktronic is deactivated after
approximately 20 seconds. The Parktronic sensors are dirty
or there is interference. X
Clean the Parktronic sensors ( Y page 214).
X Switch the ignition back on. Only the red segments in the
Parktronic
warning display are lit.
Parktronic is deactivated after
approximately 20 seconds. The problem may be caused by an
external source of radio or ultra-
sound waves. X
See if Parktronic functions in a different location. Practical advice
* optional
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Page 265 of 329
Troubleshooting
262 Problem Possible cause/consequence Suggested solutions
The key cannot be turned in the
ignition lock. The key has been in position
0 for
a considerable time. X
Remove the key and reinsert it into the ignition lock.
X Check the starter battery and recharge it if necessary
(Y page 290).
X Start the engine. The on-board voltage is too low. X
Switch off non-essential consumers, e.g. seat heating* or interior
lighting, and try to turn the key again.
If this does not work:
X Check the starter battery and recharge it if necessary
(Y page 290).
or
X Jump-start the vehicle (Y page 291).
or
X Consult a qualified specialist workshop. Practical advice
* optional
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