2014 MERCEDES-BENZ CLS fuel pressure

Engine
ProblemPossible causes/consequences andSolutions
\n
The yellow Check
Enginewarning lamp
lightsupwhile the
engineisrunning.
Theremay beamalfunction, for example:
Rin theenginemanagement
Rin thefuel injection system
Rin theexhaust system
Rin theignition system
Rin thefuel system
The emission limit values may be exceeded and theenginemay
be runninginemergencymode.
XHavethevehicle checked as soon as possible ataqualified
specialist workshop.
iIn somestates, you must immediately visitaqualified
specialist workshopassoon as theyellow CheckEngine 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.

The yellow reserve fuel
warning lamp lights up
while the engine is
running.
The fuel level has dropped into the reserve range.
XRefuel at the nearest gas station.

The yellow reserve fuel
warning lamp flashes
while the vehicle is in
motion.
In addition, the\n
Check Enginewarning
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.
XCheck that the fuel filler cap is correctly closed.
XIf the fuel filler cap is not correctly closed:close the fuel filler
cap.
XIf the fuel filler cap is closed:visitaqualified specialist
workshop.

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.
XPull 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.
XSecure the vehicle against rolling away (Ypage 167).
XConsultaqualified specialist workshop.
Indicator and warning lampsinthe instrument cluster273
On-board computer and displays
Z

XPark the vehicle onalevel surface.
Only check the coolant level when the
vehicle is onalevel surface and the engine
has cooled down.
XTurn the SmartKey to position2in the
ignition lock (Ypage 147).
On vehicles with KEYLESS-GO, press the
Start/Stop button twice (Ypage 147).
XCheck the coolant temperature display in
the instrument cluster.
The coolant temperature must be below
158‡(70 †).
XTurn the SmartKey to position
0(Ypage 147) in the ignition lock.
XSlowly turn caphalfaturn counter-
clockwise to allow excess pressure to
escape.
XTurn capfurther counter-clockwise and
remove it.
If the coolant is at the level of marker bar
$in the filler neck when cold, there is
enough coolant in coolant expansion
tank.
If the coolant level is approximately 0.6 in
(1.5 cm) above marker bar$in the fuel
filler neck when warm, there is enough
coolant in expansion tank.
XIf necessary, add coolant that has been
tested and approved by Mercedes-Benz.
XReplace capand turn it clockwise as far
as it will go.
For further information on coolant,see
(Ypage 377).
Adding washer fluid to the windshield
washer system/headlampcleaning
system
GWARNING
Windshield washer concentrate is highly
flammable. If it comes intocontactwith hot
enginecomponentsorthe exhaust systemit
could ignite. There isariskoffire and injury.
Make sure that no windshield washer
concentrate is spilled nexttothe filler neck.
XTo open:pull capupwards by the tab.
XAdd the premixed washer fluid.
XTo close:press capontothe filler neck
until it engages.
The washer fluid reservoir is used for both the
windshield washer system and the headlamp
cleaning system.
If the washer fluid level drops below the
recommended minimum of1liter,amessage
appears in the multifunction display
promptingyou to refill the washer fluid
(Ypage 262).
Further information on windshield washer
fluid/antifreeze (Ypage 378).
Maintenance
ASSYST PLUS
Service messages
The ASSYSTPLUS service interval display
informsyou of the nextservice due date.
Maintenance309
Maintenance and care
Z

Useful information
iThis Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please notethat your vehicle may
not be equipped with all features
described. This also applies to safety-
related systemsand functions.
iRead the information on qualified
specialist workshops: (Ypage 26).
Important safetynotes
GWARNING
If wheels and tires of the wrong size are used,
the wheel brakes or suspension components
may be damaged. There isarisk of an
accident.
Always replacewheels and tires with those
that fulfill the specifications of the original
part.
When replacing wheels, make sure to use the
correct:
Rdesignation
Rmodel
When replacing tires, make sure to use the
correct:
Rdesignation
Rmanufacturer
Rmodel
GWARNING
Aflat tireseverely impairs the driving,
steeringand braking characteristics of the
vehicle. There isarisk of accident.
Tires without run-flat characteristics:
Rdo not drive withaflat tire.
Rimmediately replacethe flat tirewith your
emergencyspare wheel or spare wheel, or
consultaqualified specialist workshop.
Tires with run-flat characteristics:
Rpay attention to the information and
warningnotices on MOExtended tires (tires
with run-flat characteristics).
Accessories that are not approved for your
vehicle by Mercedes-Benzorthat are not
being used correctly can impair the operating
safety.
Before purchasing and using non-approved
accessories, visitaqualified specialist
workshop and inquire about:
Rsuitability
Rlegal stipulations
Rfactory recommendations
Information on the dimensions and types of
wheels and tires for your vehicle can be found
in the "Wheel/tire combinations" section
(Ypage 362).
Information on air pressure for the tires on
your vehicle can be found:
Ron the vehicle's Tire and Loading
Information placard on the B-pillar
(Ypage 345)
Ron the tire pressure label on the fuel filler
flap (Ypage 165)
Runder "Tire pressure" (Ypage 338)
Operation
Information on driving
If the vehicle is heavily loaded, check the tire
pressures and correct them if necessary.
While driving, pay attention to vibrations,
noises and unusual handling characteristics,
e.g. pulling to one side. This may indicate that
the wheels or tires are damaged. If you
suspect thatatire is defective, reduce your
speed immediately. Stop the vehicle as soon
as possible to check the wheels and tires for
damage. Hidden tire damage could also be
causing the unusual handling characteristics.
If you find no signs of damage, have the tires
334Operation
Wheels and tires

Check
Tirepressure specifications
Important safety notes
GWARNING
Tireswithtirepressuresthatare toolow or
toohigh are associated withthefollowing
hazards:
Rthey can burst, in particular if thevehicle is
heavily laden or when driven at high
speeds.
Rthetires can wear excessively and/or
unevenly, whichcan severely impairtire
traction.
Rthe driving, steeringand braking
characteristics may be severely impaired.
There isarisk of accident.
Follow recommended tireinflation pressures
and checkthe pressure of all the tires
including the spare wheel:
Rmonthly, at least
Rif the load changes
Rbefore beginningalong journey
Runder different operating conditions,e.g.
off-road driving
If necessary, correct the tire pressure.
iThe specifications on the sample Tire and
Loading Information placard and tire
pressure tables are examples. Tire
pressure specifications are vehicle-specific
and may deviate from the data shown here.
The tire pressure specifications that are
valid for your vehicle can be found on the
Tire and Loading Information placard and
tire pressure table on the vehicle.
General notes
The recommended tire pressures for the tires
mounted at the factory can be found on the
labelsdescribed here.
Operation with the emergency spare
wheel(Ypage 367).
Further information on tire pressures can be
obtained ataqualified specialist workshop.
Tire and Loading Information placard
Recommended tire pressures
The Tire and Loading Information placard is
on the B-pillar on the driver's side
(Ypage 345).
The Tire and Loading Information placard
contains the recommended tire pressures for
cold tires. The recommended tire pressures
are valid for the maximum permissible load
and up to the maximum permissible vehicle
speed.
Tire pressuretable
The tire pressure table is on the inside of the
fuel filler flap.
Example: tire pressure table for all tires permittedfor this vehicle by the factory
The tire pressure table contains the
recommended pressures for cold tires for
various operating conditions, i.e. differing
load and speed conditions.
338Check
Wheels and tires

The tires are cold:
Rif the vehicle has been parked without
direct sunlight on the tires for at least three
hours and
Rif the vehicle has been driven for less than
1mile (1.6 km).
The tire temperature changes depending on
the outside temperature, the vehicle speed
and the tire load. If the tire temperature
changes by 18‡(10 †), the tire pressure
changes by approximately 10 kPa (0.1 bar/
1.5 psi). Take this into account when
checking the pressure of warm tires. Only
correctthe tire pressure if it is too low for the
current operating conditions. If you check the
tire pressure when the tires are warm, the
resulting value will be higher than if the tires
were cold. This is normal. Do not reduce the
tire pressure to the value specified for cold
tires. The tire pressure would otherwise be
too low.
Observe the recommended tire pressures for
cold tires:
Ron the Tire and Loading Information placard
on the B-pillar on the driver's side
Rin the tire pressure table on the inside of
the fuel filler flap
Ron the yellow label on the emergency spare
wheel (depending on the vehicle
equipment)
Underinflated or overinflated tires
Underinflation
GWARNING
Tires with pressure that is too low can
overheat and burst asaconsequence. In
addition, they also suffer from excessive and/
or irregular wear, which can severely impair
the braking properties and the driving
characteristics. There isarisk of an accident.
Avoid tire pressures that are too low in all the
tires, including the spare wheel.
Underinflated tires may:
Roverheat, leading to tire defects
Rhave an adverse effect on handling
characteristics
Rwear quickly and unevenly
Rhave an adverse effect on fuel consumption
Overinflation
GWARNING
Tires with excessively high pressure can burst
because they are damaged more easily by
road debris, potholes etc. In addition, they
also suffer from irregular wear, which can
severely impair the braking properties and the
driving characteristics. There isarisk of an
accident.
Avoid tire pressures that are too high in all the
tires, including the spare wheel.
Overinflated tires may:
Rincrease the braking distance
Rhave an adverse effect on handling
characteristics
Rwear quickly and unevenly
Rhave an adverse effect on ride comfort
Rbe more susceptible to damage
Maximum tire pressures
Example: maximum permissible tire
pressure
Never exceed the maximum permissible tire
inflation pressure. Always observe the
recommended tire pressure for your vehicle
340Check
Wheels and tires

when adjustingthetirepressure
(Ypage 338).
iThe actual values for tires are vehicle-
specific and may deviatefromthe values in
the illustration.
Checking the tire pressures
Important safety notes
Observe the notes on tire pressure
(Ypage 338).
Information on air pressure for the tires on
your vehicle can be found:
Ron the vehicle's Tire and Loading
Information placard on the B-pillar
(Ypage 345)
Ron the tire pressure label on the fuel filler
flap (Ypage 165)
Rin the "Tire pressure" section
Runder "Tire pressure" (Ypage 338)
Checking tire pressures manually
To determine and set the correct tire
pressure, proceed as follows:
XRemove the valve cap of the tire that is to
be checked.
XPress the tire pressure gauge securely onto
the valve.
XRead the tire pressure and compare it with
the recommended value on the Tire and
Loading Information placard (Ypage 338).
XIf the tire pressure is too low, increase it to
the recommended value.
XIf the tire pressure is too high, release air
by pressing down the metal pin in the valve.
Use the tip ofapen, for example. Then,
check the tire pressure again using the tire
pressure gauge.
XScrew the valve cap onto the valve.
XRepeatthese steps for the other tires.
Tire pressureloss warning system
(Canada only)
General notes
While the vehicle is in motion, the tire
pressure loss warning system monitors the
set tire pressure using the rotational speed of
the wheels. This enables the system to detect
significant pressure loss inatire. If the speed
of rotation ofawheel changes asaresult of
aloss of pressure,acorresponding warning
message will appearinthe multifunction
display.
You can recognizethe tire pressure loss
warning by theRun Flat Indicator
Active Press 'OK' to Restartmessage
which appears in theServ.menu of the
multifunction display. Further information on
the message displaycan be found under
"Restarting the tire pressure loss warning
system" section (Ypage 342).
Important safety notes
The tire pressure warning system does not
warn you of an incorrectly set tire pressure.
Observe the notes on the recommended tire
pressure (Ypage 338).
The tire pressure loss warning does not
replace the need to regularly check the tire
pressure. An even loss of pressure on several
tires at the same time cannot be detected by
the tire pressure loss warning system.
The tire pressure monitor is not able to warn
you ofasudden loss of pressure, e.g. if the
tire is penetrated byaforeign object.Inthe
event ofasudden loss of pressure, bring the
vehicle toahalt by braking carefully. Avoid
abrupt steering maneuvers.
The function of the tire pressure loss warning
system is limited or delayed if:
Rsnow chains are mounted on your vehicle's
tires.
Rroad conditionsare wintry.
Ryou are driving on sand or gravel.
Check341
Wheels and tires
Z

Ryou adoptaverysporty driving style
(cornering at high speeds or driving with
high rates of acceleration).
Ryou are driving withaheavy load(in the
vehicleoronthe roof).
Restarting the tire pressure loss
warningsystem
Restart the tire pressure loss warning system
if you have:
Rchanged the tire pressure
Rchanged the wheels or tires
Rmounted new wheels or tires
XBefore restarting, make sure that the tire
pressures are set properly on all four tires
for the respective operating conditions.
The recommendedtire pressures can be
found on the Tire and Loading Information
placard on the B-pillar on the driver's side
or the tire pressure table on the fuel filler
flap.The tire pressure loss warning system
can only give reliablewarnings if you have
set the correct tire pressure. If an incorrect
tire pressure is set, these incorrectvalues
will be monitored.
XAlsoobservethenotesinthesectionontire
pressures (Ypage 338).
XMake sure that the SmartKey is in position
2in the ignition lock (Ypage 147).
XPress the\norbutton on the
steeringwheel to selecttheServ.menu.
XPress theorbutton on the
steering wheel to select theTire
Pressuremenu.
XPress thebutton.
TheRun Flat Indicator Active
Press 'OK' to Restartmessage
appears in the multifunction display.
If you wish to confirm the restart:
XPress thebutton.
TheTire Pressure Now OK?message
appears in the multifunction display.
XPress theorbutton to select
Yes.
XPress thebutton.
TheRun Flat Indicator Restarted
message appears in the multifunction
display.
Afterateach-in period, the tire pressure
loss warning system will monitor the set
tire pressures of all four tires.
If you wish to cancel the restart:
XPress thebutton.
or
XWhen theTire Pressure Now OK?
message appears, press the
orbutton to selectCancel.
XPress thebutton.
The tire pressure values stored at the last
restart will continue to be monitored.
Tire pressuremonitor
General notes
Ifatire pressure monitor is installed, the
vehicle's wheels have sensors that monitor
the tire pressures in all four tires. The tire
pressure monitor warns you if the pressure
drops in one or more of the tires. The tire
pressure monitor only functions if the correct
sensors are installed on all wheels.
Information on tire pressures is displayed in
the multifunction display. Afterafew minutes
of driving, the current tire pressure of each
tire is shown in theServicemenu of the
multifunction display. For further information
on displaying this message, refer to the
"Checking the tire pressure electronically"
section (Ypage 344).
342Check
Wheels and tires

Example: current tire pressure display
Important safety notes
GWARNING
Each tire,including the spare (ifprovided),
should be checked at least once every two
weeks when cold and inflated to the pressure
recommended by the vehiclemanufacturer
on the Tire and Loading Information placard
on the driver'sdoor B-pillar or the tire
pressure label on the inside of the fuel filler
flap.Ifyour vehicle has tires ofadifferent size
than the size indicated on the Tire and Loading
Information placard or, if available, the tire
pressure label, you should determinethe
proper tire pressure for those tires.
As an added safety feature, your vehicle has
been equipped withatire pressure monitoring
system (TPMS) that illuminatesalow tire
pressure telltale when one or more of your
tires are significantly underinflated.
Accordingly, when the low tire pressure
telltale lights up, you should stop and check
your tires as soon as possible, and inflate
them to the proper pressure. Drivingona
significantly underinflated tire causes the tire
to overheat and can lead to tire failure.
Underinflation also reduces fuel efficiency
and tire tread life, and may affect the vehicle's
handling and stopping ability. Please note that
the TPMS is notasubstitute for proper tire
maintenance, and it is the driver's
responsibility to maintain correcttire
pressure, even if underinflation has not
reached the level to trigger illumination of the
TPMS low tire pressure telltale.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate when
the system is not operating properly. The
TPMS malfunction indicator is combined with
the low tire pressure telltale. When the
system detectsamalfunction, the warning
lamp will flash for approximatelyaminute and
then remain continuously illuminated. This
sequence will be repeated every time the
vehicle is started as long as the malfunction
exists. When the malfunction indicator is
illuminated, the system may not be able to
detect or signal low tire pressure as intended.
TPMS malfunctions may occur foravariety of
reasons, including the installation of
incompatible replacement or alternate tires
or wheels on the vehicle that prevent the
TPMS from functioning properly. Always
check the TPMS malfunction telltale after
replacing one or more tires or wheels on your
vehicle to ensure that the replacement or
alternate Tires and wheels allow the TPMS to
continue to function properly.
It is the driver's responsibility to set the tire
pressure to that recommended for cold tires
which is suitable for the operating situation
(Ypage 338). Note that the correcttire
pressure for the current operating situation
must first be taught-in to the tire pressure
monitor. If there isasubstantial loss of
pressure, the warning threshold for the
warning message is aligned to the reference
values taught-in.Restart the tire pressure
monitor after adjustingthe pressure of the
cold tires (Ypage 345). The current
pressures are saved as new reference values.
Asaresult,awarning message will appear if
the tire pressure drops significantly.
The tire pressure monitor does not warn you
of an incorrectly set tire pressure. Observe
the notes on the recommended tire pressure
(Ypage 338).
The tire pressure monitor is not able to warn
you ofasudden loss of pressure, e.g. if the
tire is penetrated byaforeign object. In the
event ofasudden loss of pressure, bring the
vehicle toahalt by brakingcarefully. Avoid
sudden steering movements
Check343
Wheels and tires
Z