check engine light MERCEDES-BENZ B-Class 2017 W246 Owner's Manual

Pre-entry climate control at time
of departure (on-board computer
)..1 64
Pre-entry climate control via key ... 105
Pre-entry climate control via key
(on-board computer) ..................... .164
Problem with the rear window
defroster ........................................ 103
Problems with cooling with air
dehumidification ............................ 101
Refrigerant ..................................... 285
Refrigerant filling capacity ............. 286
Setting the air distribution ............. 102
Setting the air vents ..................... .106
Setting the airflow ......................... 102
Setting the temperature ................ 101
Switching air-recirculation mode
on/off ............................................ 104
Switching on/off ........................... 100
Switching the rear window
defroster on/off ............................ 103
Switching the ZONE function
on/off ............................................ 102
Cockpit
Overview .......................................... 31
COMAND
Generated electricity ..................... 120
Switching on/off ........................... 202
COMAND display
Cleaning ......................................... 238
Combination switch ............................ 88
Compass
Calibrating ..................................... 229
Calling up ....................................... 228
Magnetic field zone maps .............. 229
Setting .......................................... .229
Connecting a USB device
see also Digital Operator's Man-
ual ................................................. .201
Consumption statistics (on-board
computer) .......................................... 156
Controller .......................................... .202
Convenience closing feature .............. 77
Convenience opening feature ............ 76
Convenience opening/closing (air-
recirculation mode) ........................... 104
Coolant (engine)
Checking the level ......................... 232 Filling capacity ............................... 285
Important safety notes .................. 284
Cooling
see Climate control
Copyright ............................................. 29
Cornering light function
Changing the bulb ............................ 93
Display message ............................ 178
Function/notes ................................ 89
Cruise control
Activation conditions ..................... 137
Cruise control lever ....................... 136
Deactivating ................................... 137
Display message ............................ 184
Driving system ............................... 136
Function/notes ............................ .136
Important safety notes .................. 136
Setting a speed .............................. 137
Storing and maintaining current
speed ............................................. 137
Cup holder
Center console .............................. 216
Important safety notes .................. 216
Rear compartment ......................... 217
Customer Assistance Center
(CAC) ..................................................... 27
Customer Relations Department ....... 27 D
Data see Technical data
Daytime running lamps
Display message ............................ 180
Function/notes ................................ 87
Switching on/off (on-board com-
puter) ............................................. 166
Declarations of conformity ................. 26
Departure time
Setting (on-board computer) .......... 163
Diagnostics connection ......................26
Digital Operator's Manual
Help ................................................ .21
Introduction .....................................21
Digital speedometer .........................158
DIRECT SELECT lever
Transmission ................................. 112 Index
7

vehicle in front, for vehicle speed, for braking in
good time, and for staying in lane. Always adapt your driving style to suit the prevailing road and
weather conditions and maintain a safe distance from the vehicle in front. Drive carefully.
The driving safety systems described only work
as effectively as possible when there is ade-
quate contact between the tires and the road
surface. Please pay special attention to the
notes on tires, recommended minimum tire
tread depths, etc. (Y page 257).
In wintry driving conditions, always use winter
tires (M+S tires) and if necessary, snow chains.
Only in this way will the driving safety systems
described in this section work as effectively as
possible. ABS (Anti-lock Braking System)
General information ABS regulates brake pressure in such a way that
the wheels do not lock when you brake. This
allows you to continue steering the vehicle when braking.
The 0025 ABS warning lamp in the instrument
cluster lights up when the ignition is switched
on. It goes out when the engine is running.
ABS works from a speed of about 5 mph
(8 km/h), regardless of road-surface conditions. ABS works on slippery surfaces, even when you
only brake gently.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 58). G
WARNING
If ABS is faulty, the wheels could lock when
braking. The steerability and braking charac-
teristics may be severely impaired. Addition-
ally, further driving safety systems are deac-
tivated. There is an increased danger of skid- ding and accidents.
Drive on carefully. Have ABS checked imme-
diately at a qualified specialist workshop.
When ABS is malfunctioning, other systems,
including driving safety systems, will also
become inoperative. Observe the information
on the ABS warning lamp (Y page 193) and dis-play messages which may be shown in the
instrument cluster (Y
page 168).
Braking X
If ABS intervenes: continue to depress the
brake pedal vigorously until the braking sit-
uation is over.
X To make a full brake application: depress
the brake pedal with full force.
If ABS intervenes when braking, you will feel a
pulsing in the brake pedal.
The pulsating brake pedal can be an indication
of hazardous road conditions, and functions as a reminder to take extra care while driving. BAS (Brake Assist System)
General information BAS operates in emergency braking situations.
If you depress the brake pedal quickly, BAS
automatically boosts the braking force, thus
shortening the stopping distance.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 58). G
WARNING
If BAS is malfunctioning, the braking distance
in an emergency braking situation is
increased. There is a risk of an accident.
In an emergency braking situation, depress
the brake pedal with full force. ABS prevents
the wheels from locking.
Braking X
Keep the brake pedal firmly depressed until
the emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will function as usual once you
release the brake pedal. BAS is deactivated. Driving safety systems
59Safety Z

R
to crossing traffic
R when cornering
As a result, Adaptive Brake Assist may not
intervene in all critical conditions. There is a
risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake. G
WARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions.
In such cases, Adaptive Brake Assist might:
R intervene unnecessarily
R not intervene
There is a risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake. Terminate the
intervention in a non-critical driving situation.
Due to the nature of the system, complex but
non-critical driving conditions may also cause
Active Brake Assist to intervene.
Even if Active Brake Assist is not available due to a malfunction in the radar sensor system, the
brake system is still available with full brake
boosting effect and BAS. ESP
®
(Electronic Stability Program)
General notes i
Observe the "Important safety notes" sec-
tion (Y page 58).
ESP ®
monitors driving stability and traction, i.e.
power transmission between the tires and the
road surface.
If ESP ®
detects that the vehicle is deviating from
the direction desired by the driver, one or more
wheels are braked to stabilize the vehicle. The
engine output is also modified to keep the vehi- cle on the desired course within physical limits.
ESP ®
assists the driver when pulling away on
wet or slippery roads. ESP ®
can also stabilize
the vehicle during braking. ETS (Electronic Traction System) i
Observe the "Important safety notes" sec-
tion (Y page 58).
ETS traction control is part of ESP ®
.
Traction control brakes the drive wheels indi-
vidually if they spin. This enables you to pull
away and accelerate on slippery surfaces, for
example if the road surface is slippery on one
side. In addition, more drive torque is transfer-
red to the wheel or wheels with traction.
Traction control remains active, even if you
deactivate ESP ®
.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 58). G
WARNING
If ESP ®
is malfunctioning, ESP ®
is unable to
stabilize the vehicle. Additionally, further driv- ing safety systems are deactivated. This
increases the risk of skidding and an accident.
Drive on carefully. Have ESP ®
checked at a
qualified specialist workshop.
When towing your vehicle with the front axle
raised, observe the notes on ESP ®
(Y page 253).
When towing the vehicle with the rear axle
raised, observe the notes on ESP ®
(Y page 254).
If the 00BB ESP®
OFF warning lamp lights up
continuously, ESP ®
is deactivated.
If the 00E5 ESP®
warning lamp and the 00BB
warning lamp are lit continuously, ESP ®
is not
available due to a malfunction.
Observe the information on warning lamps
(Y page 195) and display messages which may
be shown in the instrument cluster
(Y page 168).
Only use wheels with the recommended tire
sizes. Only then will ESP ®
function properly. 62
Driving safety systemsSafety

SmartKey positions
SmartKey 005A
To remove the SmartKey
(shift the transmission to position P)
0047 Power supply for some consumers, such as
the windshield wipers
0048 Ignition (power supply for all consumers)
and drive position
0049 To start the engine
i The SmartKey can be turned in the ignition
lock even if it is not the correct SmartKey for
the vehicle. The ignition is not switched on.
The drive system cannot be started.
Start/Stop button General notes
Vehicles with KEYLESS-GO are equipped with
SmartKeys featuring the integrated KEYLESS-
GO function and a detachable Start/Stop but-
ton.
A check which periodically establishes a radio
connection between the vehicle and the Smart-
Key determines whether a valid SmartKey is in
the vehicle. This occurs, for example, when
starting the drive system.
When you insert the Start/Stop button into the
ignition lock, the system needs approximately
two seconds recognition time. You can then use the Start/Stop button.
Pressing the Start/Stop button several times in
succession corresponds to the different Smart- Key positions in the ignition lock. This is only the
case if you are not depressing the brake pedal.
If you depress the brake pedal and press the
Start/Stop button, the drive system starts
immediately. To start the vehicle without actively using the
SmartKey:
R
the Start/Stop button must be inserted in the
ignition lock.
R the SmartKey must be in the vehicle.
R the vehicle must not be locked with the
SmartKey or KEYLESS-GO (Y page 66)
Do not keep the KEYLESS-GO key:
R with electronic devices, e.g. a mobile phone
or another SmartKey.
R with metallic objects, e.g. coins or metal foil.
R inside metallic objects, e.g. a metal case
This can affect the functionality of KEYLESS-GO.
If you lock the vehicle with the SmartKey remote
control or with KEYLESS-GO, after a short time:
R you will not be able to switch on the ignition
with the Start/Stop button.
R you will no longer be able to start the drive
system with the Start/Stop button until the
vehicle is unlocked again
If you lock the vehicle centrally using the button
on the front door (Y page 72), you can continue
to start the drive system with the Start/Stop
button.
The drive system can be switched off while the
vehicle is in motion by pressing and holding the Start/Stop button for three seconds.
Key positions with the Start/Stop button 0043
Start/Stop button
0044 Ignition lock
As soon as the ignition is switched on, all the
indicator lamps in the instrument cluster light
up.
For further information on situations in which an indicator lamp either fails to go out after the
drive system is started or lights up while driving, Driving
109Driving and parking Z

The braking performance of the electric motor
using recuperative braking is, in some operating modes, either reduced or not effective:
R when the condition of charge of the high-volt-
age battery increases
R if the high-voltage battery is not yet at a nor-
mal operating temperature
R when driving close to the vehicle's maximum
design speed
R when the vehicle is almost stationary
R in transmission position N
R during and after ESP stability control
If you do not make an additional effort to apply
the brake yourself, the braking effect may not be sufficient. If necessary, counteract the reduced
regenerative braking effect by applying the
brake yourself.
Radar-based recuperation The vehicle uses the Active Brake Assist sensors
during radar-based recuperation ( DAUTO
). The
sensors detect the distance to the vehicle ahead
and its speed. The intensity of recuperation is
then automatically adjusted to the current traf-
fic situation.
The range can then be increased by storing
energy efficiently. Adjustment is infinitely vari-
able from overrun mode (no recuperation) to
maximum recuperation.
Maintain sufficient distance to the vehicle in
front. Mercedes-Benz recommends that you
activate Active Brake Assist as a visual and
acoustic aid.
Examples of radar-based recuperation:
R Approaching a slower vehicle, a decelerating
vehicle or when following a vehicle downhill.
Your vehicle decelerates slightly and increa-
ses recuperation.
R Driving when no vehicle is detected in front or
when a vehicle is detected in the far distance or an accelerating vehicle is detected. Your
vehicle switches to overrun mode at higher
speeds.
R Driving on a steep downhill slope. Accelera-
tion downhill is reduced and recuperation is
increased. This is comparable with shifting
down when driving downhill. X
To activate radar-based recuperation: pull
steering wheel paddle shifter 0043or0044
towards you and hold for about one second.
X To deactivate radar-based recuperation:
briefly pull steering wheel paddle shifter 0043
or 0044 towards you.
If you change between radar-based and manual
recuperation, the following levels are activated
depending on the selection via the steering
wheel paddle shifters: 0043
Steering wheel
paddle shifter - selects
D-
(maximum
recuperation) 0044
Steering wheel
paddle shifter + selects
D+
(overrun) In particular, the function of the radar sensors
can be impaired in the case of:
R there is dirt on the sensors or anything else
covering the sensors
R there is snow or heavy rain
R there is interference by other radar sources
R there are strong radar reflections, for exam-
ple in parking garages
R a narrow vehicle is traveling in front, e.g. a
motorbike
R a vehicle is traveling in front on a different line
relative to the center of your vehicle
Following damage to the front end of the vehicle,
have the radar sensor settings and operation
checked at a qualified specialist workshop
immediately. This also applies to collisions at
slow speeds where there is no visible damage to the front of the vehicle.
If the radar sensors are not available, the system switches automatically to level Dwith moderate
recuperation. Have the radar sensors checked
at a qualified specialist workshop immediately.
Automatic adjustment of recuperation
on downhill gradients The vehicle can detect steep downhill gradients.
To reduce acceleration downhill and to charge
the high-voltage battery, recuperation is
increased steplessly. This is comparable to the
engine brake in a combustion engine when you
downshift a gear on a downhill gradient.
Automatic adjustment of recuperation on down-
hill gradients is available in level DAUTO
or on 116
TransmissionDriving and parking

Wet roads
If you have driven for a long time in heavy rain
without braking, there may be a delayed reac-
tion from the brakes when braking for the first
time. This may also occur after the vehicle has
been washed or driven through deep water.
You have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the vehicle
washed, brake firmly while paying attention to
the traffic conditions. This will warm up the
brake discs, thereby drying them more quickly
and protecting them against corrosion.
Limited braking performance on salt-
treated roads If you drive on salted roads, a layer of salt resi-
due may form on the brake discs and brake
pads. This can result in a significantly longer
braking distance.
R In order to prevent any salt build-up, apply the
brakes occasionally while paying attention to
the traffic conditions.
R Carefully depress the brake pedal and the
beginning and end of a journey.
R Maintain a greater distance to the vehicle
ahead.
Servicing the brakes !
The brake fluid level may be too low, if:
R if the red brake warning lamp lights up in
the instrument cluster and
R you hear a warning tone while the engine is
running
Observe additional warning messages in the
multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines.
Have the brake system checked immediately.
Consult a qualified specialist workshop to
arrange this.
! A function or performance test should only
be carried out on a 2-axle dynamometer. If
you wish to operate the vehicle on such a
dynamometer, please consult a qualified spe- cialist workshop in advance. You could oth-
erwise damage the drive train or the brake
system. !
As the ESP ®
system operates automatically,
the engine and the ignition must be switched
off (the SmartKey must be in position 0or 1in
the ignition lock) if:
R the electric parking brake is tested on a
brake dynamometer (for a maximum of
ten seconds)
R the vehicle is towed with the front axle
raised.
Braking triggered automatically by ESP ®
may
seriously damage the brake system.
All checks and maintenance work on the brake
system must be carried out at a qualified spe-
cialist workshop.
Have brake pads installed and brake fluid
replaced at a qualified specialist workshop.
If the brake system has only been subject to
moderate loads, you should test the functional- ity of your brakes at regular intervals.
You can find a description of Brake Assist (BAS)
on (Y page 59).
Mercedes-Benz recommends that you only have brake pads/linings installed on your vehicle
which have been approved for Mercedes-Benz
vehicles or which correspond to an equivalent
quality standard. Brake pads/linings which havenot been approved for Mercedes-Benz vehicles
or which are not of an equivalent quality could
affect your vehicle's operating safety.
Mercedes-Benz recommends that you only use
brake fluid that has been specially approved for
your vehicle by Mercedes-Benz, or which corre- sponds to an equivalent quality standard. Brakefluid which has not been approved for
Mercedes-Benz vehicles or which is not of an
equivalent quality could affect your vehicle's
operating safety.
Checking brake lining thickness You can measure the break pad/lining thick-
ness using a test gage. Color-coding (green or
red) on the test gage allows you to determine
whether the brake pad/lining thickness is still
sufficient. The test gage is in the vehicle docu-
ment wallet in the glove box. 134
Driving tipsDriving and parking

X
Reach into the gap between the hood and the
radiator trim and press hood catch lever 0044to
the left.
X Raise the hood. X
Pull support strut 0085out of bracket 0083.
X Lift up support strut 0085and insert it into yel-
low retaining clip 0087.
Closing the hood X
Raise the hood slightly and, at the same time,
remove support strut 0085from yellow retaining
clip 0087.
X Swing support strut 0085down and press it into
bracket 0083until it engages.
X Lower the 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. Do not press the hood
closed. Open the hood again and close it with a little more force. Checking and adding other service
products
Checking coolant level G
WARNING
The cooling system is pressurized, particularly when the motor is warm. If you open the cap, you could be scalded if hot coolant sprays out.
There is a risk of injury.
Let the engine cool down before you open the
cap. Wear gloves and eye protection. Slowly
open the cap to relieve pressure. !
The coolant may only be checked and cor-
rected when the engine is cool (coolant tem-
perature below 104 ‡ (40 †).Checking the
coolant when the coolant temperature is
above 104 ‡ (40 †) may result in damage to
the engine or to the engine cooling system. X
Park the vehicle on a level surface.
Only check the coolant level when the vehicle
is on a level surface and the drive system has
cooled down.
X Turn the SmartKey to position 2in the ignition
lock (Y page 109).
X Check the coolant temperature display in the
instrument cluster.
The coolant temperature must be below
104 ‡ (40 †).
X Turn the SmartKey to position 0in the ignition
lock (Y page 109).
X Slowly turn cap 0043counter-clockwise to
relieve excess pressure.
X Turn cap 0043further counter-clockwise and
remove it.
If the coolant is at the level of marker bar 0087
in the filler neck when cold, there is enough
coolant in coolant expansion tank 0044.
X If necessary, add coolant that has been tested
and approved by Mercedes-Benz.
X Replace cap 0043and turn it clockwise as far as
it will go.
For further information on coolant, see
(Y page 284).
Windshield washer system G
WARNING
Certain components in the engine compart-
ment may be very hot, e.g. the drive system
and radiator. Working in the engine compart-
ment poses a risk of injury. 232
Engine compartmentMaintenance and care

find further information in the separate operat-
ing instructions. Charging the 12‑volt battery
G
WARNING
During charging and jump-starting, explosive
gases can escape from the battery. There is a risk of an explosion.
Particularly avoid fire, open flames, creating
sparks and smoking. Ensure there is sufficient
ventilation while charging and jump-starting.
Do not lean over a battery. G
WARNING
Battery acid is caustic. There is a risk of injury. Avoid contact with skin, eyes or clothing. Do
not inhale any battery gases. Do not lean over
the battery. Keep children away from batter-
ies. Wash away battery acid immediately with
plenty of clean water and seek medical atten- tion. G
WARNING
A discharged battery can freeze at tempera-
tures below freezing point. When jump-start-
ing the vehicle or charging the battery, gases can escape from the battery. There is a risk of
an explosion.
Allow the frozen battery to thaw out before
charging it or jump-starting.
! Only use battery chargers with a maximum
charging voltage of 14.8 V.
! Only
charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment (Y page 249).
X Open the hood.
X Connect the battery charger to the positive
terminal and ground point in the same order
as when connecting the donor battery in the
jump-starting procedure (Y page 249).
If the indicator/warning lamps do not light up in
the instrument cluster at low temperatures, it is very likely that the discharged battery has fro-
zen. In this case you may neither jump-start the vehicle nor charge the battery. The service life of
a thawed-out battery may be shorter. The start-ing characteristics can be impaired, particularly at low temperatures. Have the thawed-out bat-
tery checked at a qualified specialist workshop.
Only charge the installed battery with a battery
charger which has been tested and approved byMercedes-Benz. A battery charger unit specially
adapted for Mercedes-Benz vehicles and tested
and approved by Mercedes-Benz is available as an accessory. It permits the charging of the bat-tery in its installed position. Contact an author-
ized Mercedes-Benz Center for further informa- tion and availability. Read the battery charger's
operating instructions before charging the bat-
tery. High-voltage battery – important
safety notes
G
DANGER
The vehicle's high-voltage electrical system is under high voltage. If you modify components
in the vehicle's high-voltage electrical system
or touch damaged components, you may be
electrocuted. The components in the vehi-
cle's high-voltage electrical system may be
damaged in an accident, although the damage is not visible. There is a risk of fatal injury.
Following an accident, do not touch any high- voltage components and never modify the
vehicle's high-voltage electrical system. Have
the vehicle towed away after an accident and
the vehicle's high-voltage electrical system
checked by a qualified specialist workshop. G
WARNING
In the event of a vehicle fire, the internal pres- sure of the high-voltage battery can exceed a
critical value. In this case flammable gas
escapes through a ventilation valve on the
underbody. The gas can ignite. There is a risk of injury.
Leave the danger zone immediately. Secure
the danger area at a suitable distance, whilst
observing legal requirements. 248
BatteriesBreakdown assistance

R
It is particularly important to observe the described order when connecting and disconnecting
the jumper cables.
R Never connect or disconnect the battery terminals while the engine is running. G
WARNING
A discharged battery can freeze at temperatures below freezing point. When jump-starting the
vehicle or charging the battery, gases can escape from the battery. There is a risk of an explosion.
Allow the frozen battery to thaw out before charging it or jump-starting.
! Avoid repeated and lengthy starting attempts.
Do not use a rapid-charging device to start the engine.
If the indicator/warning lamps do not light up in the instrument cluster at low temperatures, it is very likely that the discharged battery has frozen. In this case you may neither jump-start the vehicle norcharge the battery. The service life of a thawed-out battery may be shorter. Have the thawed-out
battery checked at a qualified specialist workshop.
If the 12 V battery is discharged, or after the vehicle has been jump-started, the Service
Service
Required Required Do
DoNot
Not Shift
Shift Gears
GearsVisit
VisitDealer
Dealer message appears. There is a malfunction in the
on-board voltage. Visit a qualified specialist workshop immediately.
The drive system cannot be started if the 12 V battery is discharged. This is not dependent on
whether the high-voltage battery is charged or not. The vehicle cannot be jump-started if the high-
voltage battery is discharged. The high-voltage battery must be charged first.
The drive system can be started using another vehicle. R Only use batteries with an equal nominal voltage (12 volts).
R Make sure that the battery of the donor vehicle does not have a significantly lower capacity than
the discharged battery.
R Use jumper cables with a sufficient cross-section and insulated terminal clamps from a qualified
specialist workshop, e.g. an authorized Mercedes-Benz Center.
R Make sure that the two vehicles do not touch.
R Route the jumper cables so that they cannot be caught by rotating components in the engine
compartment.
R Do not disconnect the discharged battery from the vehicle's electrical system. 250
Jump-startingBreakdown assistance