2020 MERCEDES-BENZ METRIS key battery

Disconnecting and removing
G
WARNING
During the charging process, a battery pro-
duces hydrogen gas. If a short circuit occurs
or sparks are created, the hydrogen gas can
ignite. There is a risk of an explosion.
R Make sure that the positive terminal of a
connected battery does not come into
contact with vehicle parts.
R Never place metal objects or tools on a
battery.
R It is important that you observe the
described order of the battery terminals
when connecting and disconnecting a bat-
tery.
R When jump-starting, make sure that the
battery poles with identical polarity are
connected.
R It is particularly important to observe the
described order when connecting and dis-
connecting the jumper cables.
R Never connect or disconnect the battery
terminals while the engine is running. 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
batteries. Wash away battery acid immedi-
ately with plenty of clean water and seek
medical attention.
! You should have all work involving the bat-
tery carried out at a qualified specialist
workshop.
If, in exceptional circumstances, you need
to disconnect the battery yourself, please
make sure that:
R Secure the vehicle to prevent it from roll-
ing away.
R You have switched off the engine and
removed the key. Make sure the ignition
is switched off. Check to see that there
are no indicator lamps lighting in the instrument cluster. Electronic compo-
nents such as the alternator may other-
wise be damaged.
R After the battery has been disconnected,
the parking brake is automatically
engaged. You can then no longer move
the vehicle.
R For vehicles with automatic transmission,
the transmission is locked in position P
after disconnecting the battery. You can
then no longer move the vehicle.
R You have first removed the negative ter-
minal and then the positive terminal.
Never mix up the terminal clamp discon-
nection/connection order and never mix
up the terminal clamps. The vehicle's
electronics may otherwise be damaged.
The battery and the cover of the positive ter-
minal clamp must be installed securely dur-
ing operation. Seat base (example: right-hand front seat)
The following description on disconnecting
and removing the battery is based upon the
example of the starter battery in the seat base
of the driver's seat. The additional battery is
disconnected and removed in the same way as
the starter battery. The auxiliary battery is
located in the seat base of the left-hand front
seat.
X Switch off all electrical consumers.
X Switch off the engine and remove the key
from the ignition lock.
X Open the front door on the right-hand side.
i To disconnect or remove the additional
battery, open the left-hand front door. The
auxiliary battery is located in the seat base
of the left-hand front seat. 260
BatteryMaintenance and care

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
batteries. Wash away battery acid immedi-
ately with plenty of clean water and seek
medical attention. 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.
! Vehicles with a gasoline engine:
avoid
repeated and lengthy starting attempts. Oth-
erwise, the catalytic converter could be
damaged by non-combusted fuel.
If the indicator and warning lamps in the
instrument cluster do not light up at low tem-
peratures, the discharged battery may have
frozen. In this case you may neither charge the
battery nor jump-start the vehicle. The service
life of a thawed battery may be shorter. Start-
up behavior may deteriorate, in particular at
low temperatures. Have the thawed battery
checked at a qualified specialist workshop.
Do not use a rapid charging device to start the
vehicle. If your vehicle's battery is discharged,
the engine can be jump-started from another
vehicle or from a donor battery using jumper
cables. For this purpose, the vehicle has a
jump-starting connection point in the engine
compartment.
When jump-starting, observe the following
points:
R The battery is not accessible in all vehicles.
If the other vehicle's battery is not accessi-
ble, jump-start the vehicle using a donor
battery or a jump-starting device.
R You may only jump-start the vehicle when
the engine and exhaust system are cold.
R Do not start the engine if the battery is fro-
zen. Let the battery thaw first. R
Jump-starting may only be performed from
batteries with a nominal voltage of 12 V.
R Only use jumper cables that have a suffi-
cient cross-section and insulated terminal
clamps.
R If the battery is fully discharged, attach the
battery of another vehicle for a few minutes
before attempting to start. This charges the
empty battery a little.
R Make sure that the two vehicles do not
touch.
Make sure that:
R The jumper cables are not damaged.
R Bare parts of the terminal clamps do not
come into contact with other metal parts
while the jumper cables are connected to
the battery.
R The jumper cables cannot come into contact
with parts such as the V-belt pulley or the
fan. These parts move when the engine is
started and while it is running.
Jumper cables and further information regard-
ing jump starting can be obtained at any quali-
fied specialist workshop. Before connecting the jumper cables
X Apply the parking brake.
X Shift the transmission to position j.
X Switch off all electrical consumers, e.g.
audio equipment, blower.
X Turn the key to position u in the ignition
lock and remove it .
X Open the hood (Y page 251). Connecting the jumper cable Jump-starting
273
Breakdown assistance Z

X
Push contact protection cover : of the
jump-starting connection point backwards
against the spring force as far as it will go.
The jump-starting connection point is visi-
ble. Terminal connecting plan
X Remove the cover from positive terminal =
of the donor vehicle's battery.
X Connect the positive terminal clamp of the
jumper cable to positive terminal = of the
donor vehicle's battery, and then to positive
terminal A of the jump-starting connection
point.
X Run the donor vehicle's engine at idling
speed.
X Connect the negative terminal clamp of the
jumper cable to negative terminal ; of the
donor vehicle's battery, and then to ground
contact ? of your own vehicle.
X Insert the key into the ignition lock and start
the engine.
You can now switch electrical consumers
back on except the lighting system.
X Before disconnecting the jumper cables, let
the engine run for several minutes.
X Disconnect the negative terminal of the
jumper cable from ground contact ? and
then from negative terminal ; of the donor
vehicle's battery.
X Disconnect the positive terminal clamp of
the jumper cable from positive terminal A
on the jump-starting connection point, and
then from positive terminal = of the donor
vehicle's battery.
Contact protection cover : is automatically
returned forwards to its original position by
the spring force and the jump-starting con-
nection point is closed. X
Position the cover on positive terminal = of
the donor vehicle's battery.
You can now switch on the lighting system.
X Have the battery checked at a qualified spe-
cialist workshop. Tow-starting and towing away
Important safety notes
G
WARNING
Functions relevant to safety are restricted or
no longer available if:
R the engine is not running.
R the brake system or the power steering is
malfunctioning.
R there is a malfunction in the voltage sup-
ply or the vehicle's electrical system.
If your vehicle is being towed, much more
force may be necessary to steer or brake.
There is a risk of an accident.
In such cases, use a tow bar. Before towing,
make sure that the steering moves freely. G
WARNING
You can no longer steer the vehicle if the
steering wheel lock has been engaged.
There is a risk of an accident.
Always switch off the ignition when towing
the vehicle with a tow cable or a tow bar. G
WARNING
When towing or tow-starting another vehicle
and its weight is greater than the permissi-
ble gross weight of your vehicle, the:
R the towing eye could detach itself
R the vehicle/trailer combination could roll-
over.
There is a risk of an accident.
When towing or tow-starting another vehi-
cle, its weight should not be greater than
the permissible gross weight of your vehicle.
Information on the gross vehicle weight can be
found on the vehicle identification plate
(Y page
304).274
Tow-starting and towing away
Breakdown assistance

!
Secure the tow rope or tow bar to the tow-
ing eye or trailer tow hitch only. Otherwise,
the vehicle could become damaged.
! Do not use the towing eye for recovery,
this could damage the vehicle. If in doubt,
recover the vehicle with a crane.
! Drive slowly and smoothly when towing.
Excessive tractive power could otherwise
damage the vehicles.
! Shift the automatic transmission to posi-
tion i and do not open the driver's or front
passenger's door during towing. The auto-
matic transmission may otherwise shift to
position j, which could damage the trans-
mission.
! You may tow the vehicle for a maximum
distance of 30 miles (50 kilometers). A tow-
ing speed of
30 mph (50 km/h) must not be
exceeded.
For towing distances over 30 miles
(50 kilometers), the entire vehicle must be
raised and transported.
When towing away, you must observe the legal
requirements for the country in which you are
currently driving.
It is better to have the vehicle transported
than to have it towed.
Have the vehicle transported on a transporter
or trailer if it has transmission damage.
The automatic transmission must be in posi-
tion i when the vehicle is being towed away.
If the automatic transmission cannot be shif-
ted to position i, have the vehicle transpor-
ted on a transporter or trailer.
The battery must be connected and charged.
Otherwise, you:
R cannot turn the key to position 2 in the
ignition lock.
R cannot shift the transmission to position i.
Before the vehicle is towed, switch off the
automatic locking feature (Y page 76). You could otherwise lock yourself out of the vehi-
cle when pushing or towing away the vehicle. Installing/removing the towing eye
The fixture for the front towing eye is located in
the bumper. The rear towing eye is located under the bumper.
If you tow or tow-start a vehicle, attach the
towing device to rear towing eye
;.
If your vehicle is equipped with a trailer tow
hitch, attach the towing device to the trailer
tow hitch (Y page

168).
Installing the front towing eye
X Take the towing eye and screwdriver from
the vehicle tool kit (Y page

270).
X Press the arrow on the cover : and remove
cover : from the opening.
You will see the fixture for the towing eye.
X Screw in the towing eye clockwise to the
stop.
X Insert the screwdriver into the towing eye
and tighten the towing eye.
X Stow the screwdriver in the vehicle tool kit
(Y page

270).
Removing the front towing eye
X Remove the screwdriver from the vehicle
tool kit

(Y page 270).
X Insert the screwdriver into the towing eye
and turn the screwdriver counter-clockwise. Tow-starting and towing away
275
Breakdown assistance Z