Get Breakdown assistance -> Battery (vehicle) Guide for Mercedes CLA 4 Door Third Generation (2025-2026)

When the tire pressure is correct, unscrew the

lling hose from the valve of the sealed tire.

Screw the valve cap onto the valve of the

sealed tire.

Pull the tire sealant bottle out of the tire ina-

tion compressor.

The lling hose stays on the tire sealant bottle.

Drive to the nearest qualied specialist work-

shop and have the tire, tire sealant bottle and

lling hose replaced there.

Battery (vehicle)

Notes on the 12 V battery

WARNING Risk of an accident due to work

carried out incorrectly on the battery

Work carried out incorrectly on the battery

can, for example, lead to a short circuit. This

can restrict functions relevant for safety sys-

tems and impair the operating safety of your

vehicle.

You could lose control of the vehicle in the fol-

lowing situations in particular:

When braking

In the event of abrupt steering maneuvers

and/or when the vehicle's speed is not

adapted to the road conditions

In the event of a short circuit or a similar

incident, contact a qualied specialist

workshop immediately.

Do not drive on.

Always have work on the battery carried

out at a qualied specialist workshop.

Further information on ABS (/ page 169)

Further information on ESP

(/ page 170)

For safety reasons, Mercedes-Benz recommends

that you only use batteries which have been

approved for your vehicle by Mercedes-Benz.

All vehicles except vehicles with a lithium-ion bat-

tery

WARNING Risk of explosion due to elec-

trostatic charge

Electrostatic charge can ignite the highly

explosive gas mixture in the battery.

To discharge any electrostatic charge

that may have built up, touch the metal

vehicle body before handling the battery.

The highly ammable gas mixture is created while

the battery is charging and during starting assis-

tance.

WARNING Danger of chemical burns from

the battery acid

Battery acid is caustic.

Avoid contact with the skin, eyes or

clothing.

Do not lean over the battery.

Do not inhale battery gases.

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299

Keep children away from the battery.

Immediately rinse battery acid o thor-

oughly with plenty of clean water and

seek medical attention immediately.

All vehicles

ENVIRONMENTAL NOTE Environmental

damage due to improper disposal of bat-

teries

Batteries contain pollutants. It is illegal

to dispose of them with the household rub-

bish.

Dispose of batteries in an

environmentally responsible manner.

Take discharged batteries to a qualied

specialist workshop or to a collection

point for used batteries.

If you have to disconnect the 12 V battery, con-

tact a qualied specialist workshop.

Comply with safety notes and take protective

measures when handling batteries.

Risk of explosion if the 12 V battery is

used improperly.

Fire, naked ames and smoking are pro-

hibited when handling the battery. Avoid

creating sparks.

Electrolyte or battery acid is corrosive.

Avoid contact with the skin, eyes or cloth-

ing. Wear suitable protective clothing, in

particular gloves, an apron and a face

mask. Immediately rinse electrolyte or

acid splashes o with clean water. Consult

a doctor immediately.

Do not place heavy objects on the surface

of the battery or use the battery to sup-

port a person in any way.

Wear safety glasses.

Keep children away.

Observe this Operator's Manual.

Observe the following if you do not intend to use

the vehicle over an extended period of time:

If available: activate standby mode

(/ page 167, 166).

Alternatively: connect the battery to a battery

charger approved by Mercedes-Benz or con-

sult a qualied specialist workshop to discon-

nect the battery.

Notes on the 48 V battery

WARNING Risk of an accident due to work

carried out incorrectly on the battery

Work carried out incorrectly on the battery

can, for example, lead to a short circuit. This

can restrict functions relevant for safety sys-

300

Breakdown assistance

tems and impair the operating safety of your

vehicle.

You could lose control of the vehicle in the fol-

lowing situations in particular:

When braking

In the event of abrupt steering maneuvers

and/or when the vehicle's speed is not

adapted to the road conditions

In the event of a short circuit or a similar

incident, contact a qualied specialist

workshop immediately.

Do not drive on.

Always have work on the battery carried

out at a qualied specialist workshop.

Further information on ABS (/ page 169)

Further information on ESP

(/ page 170)

ENVIRONMENTAL NOTE Environmental

damage due to improper disposal of bat-

teries

Batteries contain pollutants. It is illegal

to dispose of them with the household trash.

Dispose of batteries in an environ-

mentally responsible manner. Take dis-

charged batteries to a qualied specialist

workshop or to a collection point for

used batteries.

Have any work on the 48 V battery carried out

exclusively at a qualied specialist workshop.

Comply with safety notes and take protective

measures when handling batteries.

Risk of explosion if the 48 V battery is

used improperly.

The surface of the 48 V battery may be

hot.

Fire, naked ames and smoking are pro-

hibited when handling the battery. Avoid

creating sparks.

Electrolyte or battery acid is corrosive.

Avoid contact with the skin, eyes or cloth-

ing. Wear suitable protective clothing, in

particular gloves, an apron and a face

mask. Immediately rinse o splashes of

electrolyte or acid with plenty of clean

water. Consult a doctor immediately.

Do not place heavy objects on the surface

of the battery or use the battery to sup-

port a person in any way.

Do not perform any work on the battery.

Always have any work on the battery car-

ried out at a qualied specialist workshop.

Do not disconnect the battery yourself.

Do not remove the battery yourself. Do

not attempt to open the battery.

Keep children away.

Wear safety glasses.

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301

Observe this Operator's Manual.

Observe the following if you do not intend to use

the vehicle over an extended period of time:

If available: activate standby mode

(/ page 167, 166).

Notes on starting assistance and charging the 12

V battery

All vehicles

When charging the battery and during starting

assistance, always use the jump-start connection

point in the engine compartment.

NOTE Damage to the battery due to over-

voltage

When charging using a battery charger without

a maximum charging voltage, the battery or

the on-board electronics may be damaged.

Only use battery chargers with a maxi-

mum charging voltage of 14.8 V.

WARNING Risk of explosion due to igniting

hydrogen gas

If you cause a short circuit or sparks occur,

the hydrogen gas may ignite when a battery is

charging.

Ensure that the positive terminal of a

connected battery does not come into

contact with vehicle parts.

Never place metal objects or tools on a

battery.

When connecting and disconnecting the

battery, always observe the sequence of

battery terminals described.

When jump starting, take care to con-

nect only battery terminals of identical

polarity.

When jump starting, always observe the

sequence described for connecting and

disconnecting the jumper cables.

Do not connect or disconnect the bat-

tery terminals when the engine is run-

ning.

WARNING Risk of explosion due to a mix-

ture of explosive gases

A mixture of explosive gases can escape from

the battery during charging and jump starting.

Fire, open ames, smoking and creating

sparks must be avoided.

Make sure that there is sucient ventila-

tion.

Do not stand over the battery.

WARNING Risk of explosion from a frozen

battery

A discharged battery may freeze at tempera-

tures slightly above or below freezing point.

During starting assistance or battery charging,

battery gas can be released.

Always allow a battery to thaw before

charging it or performing starting assis-

tance.

If, at low temperatures, the indicator lamps/warn-

ing lamps in the instrument cluster do not light

up, it is highly likely that the discharged battery

302

Breakdown assistance

has frozen. In this case, you may neither charge

the battery nor jump-start the vehicle.

The service life of a battery that has been thawed

may be drastically reduced. The starting charac-

teristics can be impaired, particularly at low tem-

peratures.

We recommend having the thawed-out battery

inspected at a qualied specialist workshop.

All vehicles

NOTE Damage caused by numerous or

extended attempts to start the engine

Numerous or extended attempts to start the

engine may damage the catalytic converter

due to non-combusted fuel.

Avoid numerous and extended attempts

to start the engine.

Observe the following points during starting assis-

tance and when charging the battery:

Use only undamaged jumper cables / charg-

ing cables with a sucient cross-section and

insulated terminal clamps.

Non-insulated parts of the terminal clamps

must not come into contact with other metal

parts while the jumper cable / charging cable

is connected to the battery / jump-start con-

nection point.

The jumper cables / charging cables must not

come into contact with any parts that may

move when the engine is running

Always make sure that neither you nor the bat-

tery is electrostatically charged.

Keep away from re and open ames.

Do not lean over a battery.

Also observe the following points when charging

the battery:

Use only chargers tested and approved for

Mercedes-Benz.

Read the operating instructions for the

charger before charging the battery.

Also observe the following points during starting

assistance:

Starting assistance may only be provided

using vehicles, batteries or other jump start

devices with a nominal voltage of 12 V.

The vehicles must not touch each other.

Vehicles with a gasoline engine: only jump-

start your vehicle when the engine and

exhaust system are cold.

Starting assistance and charging the 12 V battery

Preparing for starting assistance / the charging

process

Secure the vehicle by applying the electric

parking brake.

Shi the transmission to position j.

Switch o the vehicle and all electrical con-

sumers.

Open the hood.

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303

Slide cover 1 of positive contact 2 on the

jump-start connection point in the direction of

the arrow.

Starting assistance

Connect the positive contact of your vehicle to

the jumper cable.

Connect the positive terminal of the donor

battery to the jumper cable.

Start the engine of the donor vehicle and run

it at idling speed.

Connect the negative terminal of the donor

battery to the jumper cable.

Connect ground point 3 of your vehicle to

the jumper cable.

Start the engine of your own vehicle.

Let the engines run for several minutes.

Before disconnecting the jumper cables,

switch on an electrical consumer in your own

vehicle (e.g. the rear window defroster or the

lighting).

When the starting assistance procedure is com-

plete:

Disconnect the jumper cable from ground

point 3 of your vehicle.

Disconnect the jumper cable from the nega-

tive terminal of the donor battery.

Disconnect the jumper cable from the positive

contact of your vehicle.

Disconnect the jumper cable from the positive

terminal of the donor battery.

Close cover 1 of positive contact 2 aer

removing the jumper cables.

Further information can be obtained at a qualied

specialist workshop.

Charging the 12 V battery

Connect the positive contact of your vehicle to

the charging cable.

Connect the positive terminal of the charger

to the charging cable.

Connect the negative terminal of the charger

to the charging cable.

Connect ground point 3 of your vehicle to

the charging cable.

Start the charging process.

When the charging process is complete:

Disconnect the charging cable from ground

point 3 of your vehicle.

Disconnect the charging cable from the nega-

tive terminal of the charger.

Disconnect the charging cable from positive

contact of your vehicle.

304

Breakdown assistance

Disconnect the charging cable from the posi-

tive terminal of the charger.

Aer removing the charging cable, close cover

1 of positive contact 2.

Replacing the 12 V battery

Observe the notes on the 12 V battery

(/ page 299).

Mercedes-Benz recommends that you have the

12 V battery replaced at a qualied specialist

workshop, e.g. at an authorized Mercedes-Benz

Center.

Observe the following notes if you want to replace

the battery yourself:

Always replace a faulty battery with a battery

that meets the specic vehicle requirements.

The vehicle is equipped with an AGM (Absorb-

ent Glass Mat) technology battery or a lithium-

ion battery. Full vehicle functionality is guaran-

teed only with an AGM or lithium-ion battery.

For safety reasons, Mercedes-Benz recom-

mends that you use only batteries that have

been tested and approved for your vehicle by

Mercedes-Benz.

Use detachable parts such as vent hoses,

elbow ttings or terminal covers from the bat-

tery to be replaced.

Make sure that the vent hose is always con-

nected to the original opening on the side of

the battery.

Install any existing or supplied cell caps.

Otherwise, gases or battery acid could

escape.

Make sure that detachable parts are recon-

nected in the same way.

Tow starting or towing away

Overview of permitted towing methods (not plug-

in hybrid)

NOTE Damage from automatic braking

If one of the following functions is activated,

the vehicle will brake automatically in certain

situations:

Active Brake Assist

Active Distance Assist DISTRONIC

HOLD function

Active Parking Assist

To avoid damage to the vehicle, switch o

these systems, e.g. when towing or using a car

wash.

Mercedes-Benz recommends transporting your

vehicle in the case of a breakdown, rather than

towing it away.

For towing with both axles on the ground, use a

tow rope or tow rod. Do not use tow bar systems.

Breakdown assistance

305

Breakdown assistance -> Battery (vehicle) for Your Mercedes CLA 4 Door Third Generation (2025-2026)

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