Security Locking copies & extracts from pages 28.45 of owners manual.

Due to the complex nature of the locking facilities and my being aware that many owners have not had owners handbooks passed to them with the car I have extracted the main features from the owners hand-book these relate to the A160 W168 but I have no reason to question that other W168 'A' Class are any different. The car in question is fitted with a Scorpion alarm system fitted by Mercedes-Benz UK Cars in other parts of the World may be fitted with a different anti-theft alarm system therefore please consult your owners manual for information, although all systems fitted with radio remote locking should operate in a similar way.

Do not tamper or allow others to play ,tamper with the remote car keys, apart from unnecessary use of the batteries, settings of various features on the cars locking system car be inadvertently changed, without your being aware.
Where you notice a change in the locking sequence of your car check below to correct and select the locking sequence you require.

Please note.
Reference is made in my owners manual to locking the car manually from either the drivers or passengers door, In the case of my car there is no key slot in the passenger door and i suspect this also applies to a number of other 'A' Class models.

1 Master key
2 Lock
3 To open doors
4 Locking knob,
To lock the door individually: Press the locking knob down: On the drivers door only when it is closed.
The car's equipment includes two master keys.

The key can be used to centrally lock or unlock the vehicle from the drivers door or front passenger door.

To lock or unlock the vehicle from the drivers door or front passenger door:
Turn the key in the lock to the left.
The doors tailgate and fuel flap are unlocked.
To lock the vehicle at the drivers or front passenger door:
Turn the key to the right
The tailgate and fuel filler flap are locked.

Radio remote control unit with folding key element:
1Function buttons Locked and unlocked symbols on remote key fob.
2 Small black projecting button key blade release.
3 Red lens at the blade end of the key :
battery condition indicator lamp

The radio remote control can be used to unlock and lock the vehicle from long distance away without having a direct view of the vehicle.
Radio remote control should only be used in the immediate vicinity of the off the car to prevent unauthorised access.

The vehicles equipment includes two remote control units with folding key element.

Do not expose the radio remote control unit to increased electromagnetic radiation, otherwise there could be a risk of malfunctions.

The doors tailgate and fuel filler flap can only be centrally locked unlocked using the remote control provided with your car.

On vehicles with anti-theft alarm system, the alarm may be inadvertently triggered if the vehicles unlocked manually without using the radio remote control.

The alarm can be switched off by pressing the Unlock symbol on the remote key fob. Or by inserting the key into the ignition switch and turning the key to position 2.

Remote key operation
To unlock , press the unlock symbol on the remote once only. The drivers door /doors will be unlocked along with the tailgate and fuel filler flap.

To lock, press the lock symbol on the key once only . Doors tailgate and filler flap will be locked.

The reception of the signal to lock the car and to activate the anti -theft alarm system (EDW) is verified by the indicators(Turn signal) lamps flashing three times.

Please check the the locking knobs are retracted .
If the car is locked with the remote control and then after 10 seconds a door is opened from the inside all other doors the tailgate and the fuel filler flap will remain locked.

the vehicle can not be locked using the remote control if the drivers is open.

Risk of Accident.
Do Not leave children unsupervised in the vehicle. They could open a front door even if it is locked, release the handbrake and thereby endanger themselves and others.

1If the vehicle can no longer be locked or unlocked using the remote control:
Check the batteries in the remote control unit.
2Synchonise the locking system.
Battery check press the locked or unlocked symbol on the fob for longer than 1 second. The battery charge indicator lamp ( Red lens on the key end of the remote will light up briefly if this occurs the batteries have sufficient charge, if not replace batteries as without delay.

Loss of remote control unit. Important We recommend having the mechanical locks changed.
replacement remote control units are only available through mercedes-Benz parts departments and take some time to o obtain so always keep your spare key with you.

Synchronising the locking system
If the vehicle cannot be locked or unlocked, first check the the remote control unit batteries.
If the battery charge indicator lamp light up , this means the system needs to be synchronised.
To do this:
Direct the remote control unit at the car and briefly press the lock or unlock symbols on the key fob twice within approx 30 seconds, place the key in the ignition lock and turn to position 2, the locking system is again operative.

When in the car: To centrally unlock the car, press the switch integral of the hazard warning lights switch, bottom ( door symbol with key) this will unlock if all doors were locked/lock if all doors were unlocked.
The central locking switch can only be used to lock the vehicle when the front doors are closed.
If the vehicle is locked with the central locking button and front door is opened the whole vehicle is unlocked
If the vehicle is locked using the remote control, it cannot be unlocked with the central locking switch.

PLEASE NOTE THE ABOVE PROCEDURES DO NOT OVERIDE THE CHILD LOCK FITTED ON REAR DOORS, DOORS CAN BE OPENED FROM THE OUTSIDE BUT NOT FROM INSIDE. Automatic locking when Driving The doors and tailgate are centrally locked when the vehicle reaches a certain speed.
If a front door is opened from the inside the car is centrally unlocked. Assuming it was centrally unlocked the previous time.

If the vehicle is unlocked with the central locking switch while on the move, it will remain unlocked every time it subsequently stops and sets off again, providing that no door is opened.

To select /disable the 'Automatic locking when driving function:
1Turn the key to position 2 in the ignition lock.
2Press the central locking switch (below the hazard warning tri-angle) and hold for 5 seconds approximately.
3When the signal sounds once: automatic locking function is selected
when the signal sounds twice the automatic auto locking function is disabled.

Child proof door locks
when the child proofed locking lever is in position 1(moved downwards) the door can no longer be opened from the inside.
When the switch is pushed up to its fullest extent the door can be opened from the inside.

After setting the safety door locks always check their operation by trying to open the door using the lever on the inside of each door when the lever will note lift the safety lock is ON
Note When cleaning you car it is possible inadvertently move the switch, check the switch is in the desired position before further use i.e. where child safety locks were on they one or both of the switch may now be in the unlocked position.)

DO not leave children in a car unattended, apart from opening doors the hand brake could also be released.
Remember if your children are in the back of the car and you have locked the car to ensure their safety neither they nor passers by can help them in an emergency (Lofty

Note Vehicles with anti-theft alarm system in conjunction with radio remote control.
The anti-theft alarm system is triggered when the tailgate is opened manually with the key
The alarm can be switched off by pressing the unlock symbol on the remote key fob or by inserting the key into the ignition lock and turning to position 2.
To manually unlock/lock the tailgate
To lock, turn the key clockwise. Check tailgate is locked by lifting handle the tailgate will remain closed
To unlock , turn the key anti clockwise remove the key and lift the tailgate handle. To close pull the tailgate down using the recess situated in the bottom edge of the tailgate and close from the outside with some force.


The rear number plate is only visible when the tailgate is fully closed

To unlock the drivers door in an emergency
Remove the cap (in some cases situated over the key slot)of vehicles with radio remote control.
To open the door using the key turn the key anti-clockwise. Note On vehicles with anti-theft alarm systems in conjunction with radio remote control, the anti-theft alarm system is triggered when the doors are opened.
The alarm can be switched off by pressing the unlock symbol of the key fob, or by inserting the key in the ignition lock and turning to position 2

Fuel flap emergency release
open the the right hand stowage compartment in the luggage compartment.
at this point please read the instructions on my page 6 as great care needs to be taken if attempting this procedure due the the very sharp edges of bodywork in the area. the item that you are feeling for is a small plunger which has to be pulled, that action releases the fuel filler flap.

Anti tow away protection Although I'm not aware of any 'A' class fitted with the anti tow away protection is mentioned in the handbook. Pages 44.45 if your car had this feature please read that section. If you have note got a hand book contact Mercedes-Benz for information on this feature.

With minor exception all of the above information is extracted from my 'A' Class A160 W168 handbook however it does not mention the cause of the problems if your car does not open when the remote control is operated.
When the remote is operated the car neither locks or unlocks the lamps flash as normal.
In this instance the likely cause is the vacuum pump which operates the locking system on this car. For further details on this problem mypage41

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