Page 284 of 377

Troubleshooting
28
1 Problem Possible cause/consequence Suggested solutions
3
The red brake system
warning lamp lights up
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 236).
X Under no circumstances should you top up the brake fluid. This will
not rectify the fault. D
The red coolant warning
lamp lights up while the
engine is running and the
coolant temperature
gauge is at the start of the
scale. The sensor for the coolant tem-
perature gauge is faulty.
The coolant is too hot. The engine
is not being cooled sufficiently
and may be damaged. X
Do not continue driving under any circumstances .
X Consult a qualified specialist workshop. Practical advice
204_AKB; 2; 3, en-GB
mkalafa,
2007-06-26T23:11:51+02:00 - Seite 28
1 Z
Page 289 of 377
Troubleshooting
28
6 Warning tone
s 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. Key:
X
Press the Œor the ‹button.
or
X Insert the key into the ignition lock.
The alarm is deactivated.
KEYLESS GO* :
X Grasp the exterior door handle. The KEYLESS GO key* must be
outside the vehicle .
The alarm is deactivated.
or
X Press the KEYLESS GO button* on the dashboard. The KEYLESS
GO key* must be inside the vehicle.
The alarm is deactivated. You hear a warning tone. A message appears in the multi-
function display. X
See the explanations for the display message (Y page 236). You hear a warning tone. You are driving with the parkin
g
brake on. X
Release the parking brake. Practical advice
* optional
204_AKB; 2; 3, en-GB
mkalafa,
2007-06-26T23:11:51+02:00 - Seite 28
6
Page 294 of 377

Troubleshooting
29
1 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 signal may sound
(
Y page 123). The coolant level is too low. The
coolant is too hot and the engin
e
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 209). 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 engin
e
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
204_AKB; 2; 3, en-GB
mkalafa,
2007-06-26T23:11:51+02:00 - Seite 291
Page 296 of 377

Troubleshooting
29
3 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 230).
X Switch the ignition back on. Only the red segments in the
Parktronic warning display are lit.
Parktronic is deactivated afte
r
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
* optiona l
204_AKB; 2; 3, en-GB
mkalafa,
2007-06-26T23:11:51+02:00 - Seite 293