
Problem Possible causes/consequences and 
M Solutions$ (USA only)
J (Canada only)
The red brake system
warning 
lamp comes on
while the vehicle is
moving. A warning tone
also sounds. You are driving with the parking brake applied.
X
Release the parking brake.
The warning lamp goes out and the warning tone ceases. 6
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 Drive on carefully.
X Have SRS checked at a qualified specialist workshop
immediately.
For further information about SRS, see (Y page 41). Indicator and warning lamps in the instrument cluster
281
On-board computer and displays Z 

Engine
Problem Possible causes/consequences and 
M Solutions;
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 a gasoline engine)
R in the fuel system
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
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. Vehicles with a diesel engine: the fuel tank has been run dry
(Y page 172).
X
Start the engine three to four times after refueling.
If the yellow Check Engine warning lamp goes out, emergency
running mode is canceled. The vehicle need not be checked. 8
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. 8
The yellow reserve fuel
warning lamp flashes
while the vehicle is in
motion.
In addition, the ;
Check 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. 282
Indicator and warning lamps in the instrument cluster
On-board computer and displays 

Problem Possible causes/consequences and 
M Solutions?
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 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 175).
X Consult a qualified specialist workshop. Indicator and warning lamps in the instrument cluster
283
On-board computer and displays Z 

Problem Possible causes/consequences and 
M Solutions?
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 175).
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 331).
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
under 
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. ?
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 175).284
Indicator and warning lamps in the instrument cluster
On-board computer and displays 

Problem Possible causes/consequences and 
M SolutionsX
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 331).
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 At coolant temperatures under 248 ‡  (120 †), drive to the next
qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic. Driving systems
Problem Possible causes/consequences and 
M Solutions·
The red distance
warning lamp lights up
while the vehicle is in
motion. 
A warning tone
also sounds. You are approaching a vehicle or a stationary obstacle in your line
of travel at too high a speed.
X
Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to
brake or take evasive action.
Further information on DISTRONIC PLUS ( Y page 185).
Further information on PRE-SAFE ®
 Brake (Y page 72). Indicator and warning lamps in the instrument cluster
285
On-board computer and displays Z 

Tires
Problem Possible causes/consequences and 
M Solutionsh
USA only:
The 
yellow tire pressure
monitor warning lamp
(pressure loss/
malfunction) is lit.
Canada only:
The yellow tire pressure
monitor warning lamp
(pressure loss) is lit. The tire pressure monitor has detected a loss of pressure in at
least one of the tires.
G WARNING
With tire pressures which are too low, there is a risk of the
following hazards:
R they may burst, especially as the load and vehicle speed
increase.
R they 
may wear excessively and/or unevenly, which may greatly
impair tire traction.
R the driving characteristics, as well as steering and braking, may
be greatly impaired.
There is a risk of an accident.
X Stop the vehicle without making any sudden steering or braking
maneuvers. 
Pay attention to the traffic conditions as you do so.
X Secure the vehicle against rolling away ( Y page 175).
X Observe the additional display messages in the multifunction
display.
X If there is a flat tire, inspect the tires ( Y page 344).
X Check the tire pressure (Y page 370).
X If necessary, correct the tire pressure. h
USA only:
The 
yellow tire pressure
monitor warning lamp
(pressure loss/
malfunction) flashes for
approximately one
minute and then
remains lit. The tire pressure monitor is faulty.
G WARNING
The system is possibly unable to recognize or register low tire
pressure.
There is a risk of an accident.
X Observe the additional display messages in the multifunction
display.
X Visit a qualified specialist workshop.286
Indicator and warning lamps in the instrument cluster
On-board computer and displays 

Example: tire pressure table with tire dimensions
If 
a tire size precedes a tire pressure, the tire
pressure information following is only valid
for that tire size. The load conditions "partially
laden" and "fully laden" are defined in the
table for different numbers of occupants and
amounts of luggage. The actual number of
seats may differ. Some tire pressure tables show only the rim
diameters instead of the full tire size, e.g.
R18. The rim diameter is part of the tire size
and can be found on the tire sidewall
(Y page 378).
If the tire pressures have been set to the
lower values for lighter loads and/or lower
road speeds, the pressures should be reset
to the higher values:
R
if you want to drive with an increased load
and/or
R if you want to drive at higher road speeds.
i The tire pressures for increased loads
and/or higher road speeds, shown in the
tire pressure table, may have a negative
effect on driving comfort. If the tire pressure is not set correctly, this
can 
lead to an excessive build up of heat and
a sudden loss of pressure.
For more information, contact a qualified
specialist workshop. Important notes on tire pressure
G
WARNING
If the tire pressure drops repeatedly, the
wheel, valve or tire may be damaged. Tire
pressure that is too low may result in a tire
blow-out. There is a risk of an accident.
R Check the tire for foreign objects.
R Check 
whether the wheel is losing air or the
valve is leaking.
If you are unable to rectify the damage,
contact a qualified specialist workshop. G
WARNING
If you fit unsuitable accessories onto tire
valves, 
 the tire valves may be overloaded and
malfunction, which can cause tire pressure
loss. Due to their design, retrofitted tire
pressure monitors keep the tire valve open.
This can also result in tire pressure loss. There
is a risk of an accident.
Only screw the standard valve cap or other
valve caps approved by Mercedes-Benz for
your vehicle onto the tire valve.
Use a suitable pressure gauge to check the
tire pressure. The outer appearance of a tire
does not permit any reliable conclusion about
the tire pressure. On vehicles equipped with
the electronic tire pressure monitoring
system, the tire pressure can be checked
using the on-board computer.
The tire temperature and pressure increase
when the vehicle is in motion. This is
dependent on the driving speed and the load.
Therefore, you should only correct tire
pressures when the tires are cold. Tire pressure
367
Wheels and tires Z     

values indicated by a pressure gauge are
higher than those shown by the on-board
computer. 
In this case, do not reduce the tire
pressures.
The operation of the tire pressure monitor can
be affected by interference from radio
transmitting equipment (e.g. radio
headphones, two-way radios) that may be
being operated in or near the vehicle.
i USA only:
This device complies with part 15 of the
FCC Rules. Operation is subject to the
following two conditions:
1. This device may not cause interference,
and
2. this device must accept any interference
received, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
i Canada only:
This device complies with RSS-210 of
Industry Canada. Operation is subject to
the following two conditions:
1. This device may not cause interference,
and
2. this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
Checking tire pressure electronically X
Make sure that the SmartKey is in
position  2 (Y 
page 153) in the ignition lock.
X Press the = or ; button on the
steering wheel to select the Serv. menu. X
Press the 9 or : button to select
Tire Pressure.
X Press button a.
The 
 current tire pressure for each wheel will
be displayed in the multifunction display.
If the vehicle was parked for longer than
20 minutes the  Tire pressures will be 
displayed after driving a few 
minutes message is shown.
After a teach-in period, the tire pressure
monitor 
automatically recognizes new wheels
or new sensors. If a clear allocation of the tire
pressure values to the individual wheels is not
possible, the message is shown instead of the
tire pressure display. The tire pressures are
already being monitored.
i If an emergency spare wheel is mounted,
the system may continue to show the tire
pressure of the wheel that has been
removed for a few minutes. If this occurs,
note that the value displayed for the
position where the spare wheel is mounted
is not the same as the current tire pressure
of the emergency spare wheel.
Tire pressure monitor warning
messages If the tire pressure monitor detects a
significant 
pressure loss on one or more tires,
a warning message is shown in the
multifunction display. A warning tone also
sounds and the tire pressure warning lamp
lights up in the instrument cluster.
Each tire that is affected by a significant loss
of pressure is highlighted in the pressure
display.
X If the  Correct Tire Pressure message
appears 
 in the multifunction display, check
the tire pressure on all four wheels and
correct it if necessary.
i If the wheel positions on the vehicle are
interchanged, the tire pressures may be
displayed for the wrong positions for a
short time. This is rectified after a few 372
Tire pressure
Wheels and tires