Get Opening and closing -> SmartKey Guide for Mercedes CLA 4 Door Third Generation (2025-2026)

SmartKey

Overview of SmartKey functions

WARNING Risk of accident and injury due

to children le unattended in the vehicle

If you leave children unattended in the vehicle,

they could, in particular:

open doors, thereby endangering other

persons or road users.

get out and be struck by oncoming trac.

operate vehicle equipment and become

trapped, for example.

In addition, the children could also set the

vehicle in motion by, for example:

releasing the parking brake.

changing the gearbox position.

starting the vehicle.

Never leave children unattended in the

vehicle.

When leaving the vehicle, always take the

key with you and lock the vehicle.

Keep the key out of reach of children.

NOTE Damage to the SmartKey caused by

magnetic elds

Keep the SmartKey away from strong

magnetic elds.

Vehicle key with panic alarm

Locks

Indicator lamp

Unlocks

Opens the trunk lid

Panic alarm

If indicator lamp 2 does not light up when

the Ü or ß button is pressed, the bat-

tery is weak or possibly discharged. Replace

the battery as soon as possible.

Replace the SmartKey battery (/ page 71).

The SmartKey locks and unlocks the following

components:

Doors

Fuel ller ap

Trunk lid

If the vehicle is not opened within approximately

40 seconds aer unlocking, it locks again. Anti-

the protection is armed again.

Do not keep the SmartKey together with elec-

tronic devices or metal objects. This can aect

the SmartKey's functionality.

Opening and closing

Activating/deactivating the acoustic locking veri-

cation signal

Multimedia system:

Settings

Vehicle

Open/Close

Activate or deactivate the Acoustic Lock.

Activating/deactivating the panic alarm

Requirements

The vehicle is switched o.

To activate: press button 1 for approximately

one second.

A visual and audible alarm is triggered.

To deactivate: briey press button 1 again.

Press the start/stop button.

A key belonging to the vehicle must be detec-

ted in the vehicle.

Changing the unlocking settings

Possible unlocking functions of the SmartKey:

Central unlocking

Unlocking the driver's door and fuel ller ap

To switch between settings: press the Ü

and ß buttons simultaneously for approx-

imately six seconds until the indicator lamp

ashes twice.

Options when the unlocking function for the driv-

er's door and fuel ller ap has been selected:

To unlock the vehicle centrally: press the

Ü button twice.

Vehicles with KEYLESS-GO: if you touch the

inner surface of the door handle on the driv-

er's door, only the driver's door and the fuel

ller ap will be unlocked.

Deactivating the function of the key

Vehicles with KEYLESS-GO: if you deactivate the

function of the SmartKey, the KEYLESS-GO func-

tions will also be deactivated. Access or drive

authorization by KEYLESS-GO will then no longer

be possible with that particular SmartKey. Acti-

vate the function of the SmartKey so that all its

functions will again be available.

You can also deactivate the function of the Smart-

Key to reduce the energy consumption of the

SmartKey if you do not use the vehicle or a Smart-

Key for an extended period of time.

Press and hold the ß button on the Smart-

Key.

Opening and closing

With the key button ß pressed, immedi-

ately press key button Ü twice in quick

succession.

The indicator light of the key lights up once

briey and once for a long time.

The following options for re-activating the

SmartKey are available:

Press any button on the SmartKey.

Start the vehicle with the SmartKey in the

marked space in the center console

(/ page 138).

Removing/inserting the mechanical key

Removing the mechanical key

Press release button 1.

Emergency key

2 is pushed out slightly.

Pull out mechanical key 2 until it engages in

the intermediate position.

Press release button 1 again and fully

remove mechanical key

Inserting the mechanical key

Press release button 1.

Insert mechanical key 2 to the intermediate

position or fully until it engages.

You can use the intermediate position of

mechanical key 2 to attach the key to a key

ring.

Replacing the key battery

DANGER Risk of fatal injury due to swal-

lowing batteries

Batteries contain toxic and corrosive substan-

ces. If batteries are swallowed or otherwise

enter the body, severe internal burns can

occur within two hours.

There is a risk of fatal injury!

Keep the batteries out of the reach of

children.

If the lid and/or the battery compart-

ment do not close securely, stop using

the key and keep it away from children.

If batteries are swallowed or otherwise

enter the body, seek immediate medical

attention.

Opening and closing

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.

Requirements

You require a CR 2032 3 V cell battery.

Mercedes-Benz recommends that you have the

battery replaced at a qualied specialist work-

shop.

Remove the mechanical key (/ page 71).

Press release knob 2 down fully and slide

cover

1 in the direction of the arrow.

Fold out cover 1 in the direction of the arrow

and remove.

Remove battery compartment 3 and take

out the discharged battery.

Insert the new battery into battery compart-

ment 3. Observe the positive pole marking in

the battery compartment and on the battery

when doing this.

Push in battery compartment 3.

Re-attach cover 1 and push it until it

engages.

Problems with the key, troubleshooting

You can no longer lock or unlock the vehicle

Possible causes are:

The key battery is weak or discharged.

Check the battery using the indicator lamp

(/ page 69).

Replace the key battery, if necessary

(/ page 71).

Use the replacement key.

Use the mechanical key to lock or unlock

(/ page 76).

Have key checked at a qualied specialist

workshop.

There is interference from a powerful radio signal

source

Possible causes if the function of the key is

impaired:

high voltage power lines

mobile phones

electronic devices (notebooks, tablets)

Opening and closing

shielding due to metal objects or induction

loops for electrical gate systems or automatic

barriers

Make sure that there is sucient distance

between the key and the potential source of

interference.

You have lost a key

Have the key deactivated at a qualied spe-

cialist workshop.

If necessary, have the mechanical lock

replaced as well.

Doors

Unlocking/opening the doors from the inside

To unlock and open a front door: pull door

handle

To unlock a rear door: pull the rear door han-

dle.

To open a rear door: pull the rear door handle

again.

Centrally locking and unlocking the vehicle from

the inside

To unlock: press 1 button.

To lock: press button 2.

The red indicator lamp on button

2 lights up

once the vehicle is locked.

The buttons are also on the front passenger

door.

Opening and closing

Opening and closing -> SmartKey for Your Mercedes CLA 4 Door Third Generation (2025-2026)

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