check engine MERCEDES-BENZ M-Class 2014 W166 Service Manual

Display messages Possible causes/consequences and
0001 Solutions
LOW RANGE Stop
Apply Parking Brake Ag
earshift process has been canceled. LOW RANGE is in the
neutral position .There is no connection between the engine and
the drive wheels.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Apply the electric parking brake. Do not continue driving under
any circumstances.
X Repeatt he gearshift process. LOW RANGE
Malfunction To
park, Apply Brake LOW RANGE is malfunctioning.
X
Do not drive at speeds above 50 mph (80 km/h).
X When parking, secure the vehicle against rolling away
(Y page 179).
X Have the vehicle checked at a qualified specialist workshop. LOW RANGE Max.
Speed 25 mph You have exceeded the maximum speed for the gearshift process.
X
Drive more slowly.
The gear change is made. LOW RANGE Max.
Speed 40 mph You have exceeded the maximum speed for the gearshift process.
X
Drive more slowly.
The gear change is made. LOW RANGE Shift to
Position N Briefly You have reduced the vehicle speed, but the automatic
transmission is not in position
N.
X Briefly shift the automatic transmission to position N.LOW RANGE Shifting
Canceled Please
Reactivate The gearshift process has been canceled.
X
Repeatt he gearshift process. 0001
Inoperative DSR (Downhill Speed Regulation) is deactivated due to a
malfunction.
X
Have DSR checked at a qualified specialist workshop. 0001
Off The HOLD function is deactivated. The vehicle is skidding.
Aw
arning tone also sounds.
X Reactivate the HOLD function later (Y page 206).Radar Sensors
Deactivated See
Operator's Manual The radar sensor system is deactivated.
X
Switch on the radar sensor system (Y page 276).304
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
0001 Solutions
DISTRONIC PLUS
Currently
Unavailable See
Operator's Manual DISTRONIC PLU
Sis temporarily inoperative. Possible causes are:
R the function is impaired due to heavy rain or snow.
R the sensors in the radiator grill and the bumper are dirty.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations or other sources of electromagnetic radiation.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
Aw arning tone also sounds.
When the causes stated above no longer apply, the display
message disappears.
DISTRONIC is operational again.
If the display message does no tdisappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 179).
X Clean the sensors in the radiator grill and the bumper
(Y page 374).
X Restar tthe engine. DISTRONIC PLUS
Inoperative DISTRONIC PLUS is defective.
BAS PLUS (Brake Assist PLUS) and PRE-SAFE
®
Brake may be
inoperative as well.
Aw arning tone also sounds.
X Visi taqualified specialist workshop. DISTRONIC PLUS
Passive You have depressed the accelerator pedal. DISTRONIC PLUS is no
longer controlling the speed of the vehicle.
X
Remove your foot from the accelerator pedal. DISTRONIC PLUS
- - - mph An activation condition for DISTRONIC PLUS is not fulfilled.
X
Check the activation conditions for DISTRONIC PLUS
(Y page 194). 308
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
0001 Solutions
0001
Remove 'Start'
Button and Insert
Key KEYLESS-GO is temporarily malfunctioning or is defective. A
warning tone also sounds.
X
Insert the SmartKey into the ignition lock and turn it to the
desired position.
X Visit a qualified specialist workshop. 0001
Close Doors to
Lock Vehicle At leas
tone door is open. Awarning tone also sounds.
X Close all doors and loc kthe vehicle again. Warning and indicator lamps in the
instrument cluster
Overview
000D Low-beam headlamps
(Ypage 121)
0016 Parking lamps (Y page 122)
000C High-beam headlamps
(Ypage 124)
00070006 Turn signal (Ypage 123)
0014 Seat belts (Ypage 317)
0011 (USA) Brakes (Y page 318)
0008 (Canada)B rakes (Ypage 318)
0019 ABS (Ypage 319)
000F ESP®
(Y page 321)
0017 ESP®
OFF (Y page 321)
0007 (USA) Electric parking brake (red)
(Ypage 324)
000C (Canada )Electric parking brake (red)
(Y page 324)
000C Electric parking brake
(yellow) (Y page 324)
001F SRS (Ypage 324)
0010 Check Engine (Y page 325)
0012 Reserve fuel (Ypage 325)
000E Coolant (Ypage 326)
000E Distance warning function
(Ypage 328) 000F
Diesel engine: preglow
(Y page 159)
0012 Tire pressure monitor
(Ypage 329) 316
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Problem Possible causes/consequences and
0001 Solutions
000F
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 72), it may be best to deactivate ESP ®
. 0017
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 72), 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 Have ESP ®
checked at a qualified specialist workshop. 000F0017
The yellow ESP
®
and
ESP ®
OFF warning
lamps are lit while the
engine is running. ESP
®
,B AS, BAS PLUS, PRE-SAFE ®
,P RE-SAFE ®
Brake ,COLLISION
PREVENTION ASSIST, the HOLD function, hill start assist and
ESP ®
trailer stabilization 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. 322
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Problem Possible causes/consequences and
0001 Solutions
0007
(USA only)
000C (Canada only)
The red electric parking
brake indicator lamp
flashes or lights up
and/or
000C
warning lamp for the
electric parking brake
lights up. X
Observe the additional display messages in the multifunction
display. 001F
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 43).324
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Engine
Problem Possible causes/consequences and
0001 Solutions
0010
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 engin emay
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 Chec kEngine 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 176).
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. 0012
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. 0012
The yellow reserve fuel
warning lamp flashes
while the vehicle is in
motion.
In addition, the
0010
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. Warning and indicator lamps in the instrument cluster
325On-board computer and displays Z

Problem Possible causes/consequences and
0001 Solutions
000E
The red coolant
warning lamp comes on
while the engine is
running. The coolant level is too low.
!
Avoid making long journeys with too little coolant in the engine
cooling system. The engine will otherwise be damaged.
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 179).
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 367).
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. 000E
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 whe nyour 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. Warning and indicator lamps in the instrument cluster
327On-board computer and displays Z

Problem Possible causes/consequences and
0001 Solutions
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 179).
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 367).
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
0001 Solutions
000E
The red distance
warning function
warning lamp comes on
while the vehicle is
moving. A warning tone
also sounds.
You are approaching a vehicle or a stationary obstacle in you
rline
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 194).
Further information on PRE-SAFE ®
Brake (Y page 74).
Further information on the distance warning function
(Y page 69). 328
Warning and indicator lamps in the instrument clusterOn-board computer and displays

could otherwise damage the windshield
wipers or the hood. X
Make sure that the windshield wipers are
turned off.
X Pull release lever 0002on the hood.
The hood is released. X
Reach into the gap, pull hoo dcatch
handle 0003up and lift the hood.
If you lift the hood by approximately 15 in
(40 cm), the hood is opened and held open
automatically by the gas-filled strut.
Closing the hood X
Lowe rthe hood and let it fall from a height
of approximately 8 in (20 cm).
X Check that the hood has engaged properly.
If the hood can be raised slightly, it is not
properly engaged. Open it again and close
it with a little more force. Radiator
Vehicles with adiesel engine: do not cover
the radiator, for example with a winter front
or bug cover. The reading softhe on-board-
diagnostic system may otherwise be
inaccurate. Some of these readings are
required by law and must be accurate at all
times. Engine oil
General notes Depending on the driving style, the vehicle
consumes up to 0.9 US qts (0.8 l) of oil over
a distance of 600 miles (1000 km). The oil
consumption may be higher than this when
the vehicle is new or if you frequently drive at
high engine speeds.
Depending on the engine, the oil dipstick may
be in a different location.
When checking the oil level:
R park the vehicle on a level surface.
R the engine should be switched off for
approximately five minutes if the engine is
at normal operating temperature.
R if the engine is not at normal operating
temperature, e.g. if the engine was only
started briefly: wait about 30 minutes
before carrying out the measurement.
Checking the oil level using the oil
dipstick G
WARNING
Certain components in the engine
compartment, such as the engine, radiator
and parts of the exhaust system, can become
very hot. Working in the engine compartment
poses a risk of injury.
Where possible, let the engine cool down and
touch only the components described in the
following. Engine compartment
365Maintenance and care Z

Example: engine oil cap
X
Turn cap 0002counter-clockwise and remove
it.
X Add engine oil.
If the oil level is at or below the MIN mark
on the oil dipstick, add 1.1 US qt (1.0 l) of
engine oil.
X Replace cap 0002on the filler neck and turn
clockwise.
Ensure that the cap locks into place
securely.
X Check the oil level agai nwith the oil
dipstick (Y page 365).
Further information on engine oil
(Y page 448). Additional service products
Checking coolant level G
WARNING
Certain components in the engine
compartment, such as the engine, radiator
and parts of the exhaust system, can become
very hot .Working in the engine compartment
poses a risk of injury.
Where possible, let the engine cool down and
touch only the components described in the
following. G
WARNING
The engine cooling system is pressurized,
particularly when the engine is warm. When opening the cap, you could be scalded by hot
coolant spraying out. There is a risk of injury.
Let the engine cool down before opening the
cap. Wear eye and hand protection when
opening the cap. Open the cap slowly half a
turn to allow pressure to escape. X
Park the vehicle on a level surface.
Only check the coolant level when the
vehicle is on a level surface and the engine
has cooled down.
X Turn the SmartKey to position 2in the
ignition lock (Y page 157).
On vehicles with KEYLESS-GO, press the
Start/Stop button twice (Y page 158).
X Check the coolant temperature gauge in
the multifunction display.
The coolant temperature must be below
158 ‡ (70 †).
X Turn the SmartKey to position
0(Y page 157) in the ignition lock.
X Slowly turn cap 0002half a turn counter-
clockwise to allow excess pressure to
escape.
X Turn cap 0002further counter-clockwise and
remove it.
If the coolant is at the level of marker bar
0023 in the filler neck when cold, there is
enough coolant in coolant expansion
tank 0003.
If the coolant level is approximately 0.6 in
(1.5 cm) above marker bar 0023in the filler
neck when warm, there is enough coolant
in expansion tank 0003. Engine compartment
367Maintenance and care Z