Remote Ignition Keys Central locking

Lastest information on remote key costs, Having mislaid or disposed of a key I found it necessary to order a new key , Needless to say I now expecting the lost one to turn up but we will see.
The master key W169 MA906 905 89 00 costs 171.67
The metal key blade that is stowed in the remote key is MA69 760-25-06 28.48 making a total of 240-18 , neither portion of the key was available immediately 24 hours for the remote portion and 3-5 days for the key blade
so having a spare key is vital if you used your car for commuting etc. Or you will be on public transport for days and will have no way of getting to MB to even order the new Key. You will also want your registration documents Photo ID, proof of purchase/ownership and of course a means of paying up front.
The key details are held by MB and is made based on the chassis/vin number . I mention on this page an alternative outlet for ignition keys however I would have had to drive to Birmingham from the south coast and that would have cost vas much for fuel and time as going to my local MB parts department. their price would have been 100-00 less for what they say is an MB key , beware I understand that some parts outlets are selling Japanese copies of keys which may or may not work with your car.

The blade-less or 'Smart key', remote ignition key should eliminate mechanical wear as experienced with the w168. You will be required to provide proof of ownership with a document on which your photograph appears, such as driving license. However the key if dropped is more likely to become damaged which may render it unusable, so try to avoid dropping your keys.
New keys cost in excess of 200.00 and as far as Mercedes-Benz are concerned can only be purchased from them
However if you have problems see the link at the bottom of the page it could solve your problems and save you money.

Many W169 owners may already be aware of this problem:-

If you go to your car and open it using the remote key and only go to the boot area without opening the drivers door the car will automatically lock fully when you close the boot!

I learnt this lesson the hard way and had to get the spare set of keys brought to me at the trout fishery, some 25 miles from my home where I had changed my wet clothes and prepared to drive home, only then to find that when I closed the boot the car had locked complete with the keys laying in the boot in full view.

Either put the keys in your pocket of the cloths you going to wear home or better still put them in the ignition, the car will not then lock itself and you will save yourself and others a lot of aggravation .

What you do if you only have one set of keys, short of breaking a rear quarter light (window) I have no idea certainly the car seems pretty secure when locked.

The batteries in your key can be tested by pressing either the lock or unlock button, if the batteries are in a usable condition you will see a red light flash above the locking segment, as shown in the photograph on the left.
This feature is barley detectable when looking at the key case

Should your Remote key fail to open the car you will need to use the emergency key blade:-
Withdraw the blade from its housing in the remote key by sliding the spring loaded retaining catch the direction of the arrow shown in the photo:-
1. Place the blade into the door lock and turn (clockwise Right Hand Drive vehicles)(Left Hand Drive Vehicles, Anti-clockwise )
2.Turn the emergency key blade in the door.
3.Take hold of the door handle pulling firmly toward you
4. The door lock button will be seen to pop up the door will open, remove the key blade from the door lock.
Note , that the key blade is only used to unlock the car not lock it. see procedure below or your hand book for details
5. At which point the alarm will sound.
6. Stop the alarm by pressing either the lock or unlock segments on the key. Or place the remote key in the ignition key housing.

Note if the batteries in the remote key are low powered or dead, pressing the segments on the key may not turn off the alarm

The remote key will start your car even though the remote fob batteries are flat.

Opening the door in an emergency.
Please be patient the DVD will take time to load but the wait may well prove to be worth it Unless you are already familiar with the procedure.

It is strongly recommended that you do a trial run on your car using this procedure, if there is more than one driver then make them aware of the procedure it may save you a lot of grief and embarrassment in the longer term

Remember to replace the key blade (Emergency key) back into the fob, you will hear a click when it is fully installed.

Replacing remote key batteries

If when undertaking the battery test above the key fails to show a battery condition light , change the batteries as soon as possible or use your spare key.

A. Remove the emergency key housed in the key as shown above.
B. Using the key blade push on the spring loaded battery cage locking devise, this will allow you to ease the battery cage out from the key body. 1 & 2 on the photo.


Having carefully removed the cage remove the dead batteries and dispose of them in a safe manner.
Replace the two batteries with New lithium CR2025 cells avoid touching the battery contacts, these are available from MB parts and other battery suppliers.
Re-assemble the remote key components and test as above.

If you are getting your vehicle serviced by Mercedes Workshops these should be changed when your car is serviced. Check your invoice for the New Batteries.

If the wrong ignition key is used the key will turn but not start the vehicle.

2018 Replacement key has slightly different procedure for changing the battery.
1. Remove the Key blade in the same way as earlier keys, slide the toothed slide and remove blade
2. With the blank side of the key facing you insert the blade in the slot from which the blade was removed
3. With the blade located to the right gently push the blade into the slot , this will press down of a small plastic catch and release the back of the casing.
4. When the cover has popped open remove the cover this will expose the single battery.
5. Remove the used battery and replace with new battery.
6. There is no test facility on this new key so change your batteries annually to ensure you do not finish up with an inoperable remote key.
7. Also familiarise yourself with the procedure for using the key blade to access your car
8. Having replaced the battery Check correct operation with the vehicle

The blade less key has a reflective disc in the end which marries with the responder in the ignition switch , to extend the life of your remote key's try to protect this feature by not putting in the same pocket as your small change coinage ,etc.
I suspect that if this surface is substantially scuffed the car will refuse to accept the key.

There are three key positions:-
A. Position 1. Ignition Off
B. Position 2 Ignition ON
C. Start position, Release when car starts.
Note On my model Classic SE, with Eco-start, the clutch and or brake have to be depressed before the car will start even though the key is turned to the start position.

Locking your car in an emergency (remote key fails to work)

You can lock your car in Emergency even when the remote key will not work.
1. On leaving the car, ensure you have the keys in hand.
2. Ensure the front and rear passenger near side doors, and boot lid are fully closed
3. Open the rear passenger door behind the driver.
4. To Lock the passenger doors on the near side (passenger side) press the switch marked with a closed lock a situated on the drivers door card.
The closed doors will be heard to lock, the plungers going down. The boot will also have been locked
5. Now close the drivers door and push the locking plunger down, from the inside of the car. (You cannot do this with the drivers door open)
6. The plunger on the rear drivers side passenger door will already be down.
7. Firmly close the rear passenger door. The car is now fully locked.
See procedure above for opening drivers door using the emergency key blade.

Locking the car when the Main Battery has been removed for recharge,
8. It is unlikely that the central locking will work due to the main battery having been removed. In the same way the switches on the drivers door card will be dead. therefore secure the car by:-
9. Manually pressing the door plungers down on the near side of the car.
10. With the rear off side passenger door open, reach in and press the plunger down on the drivers closed door.
11. Now press the plunger down of the rear off side passenger door and firmly close the door.
12. Note Although all four doors will be locked which affords some security the boot will remain unlocked.

If you have Eco-Start on your vehicle then the door locks may remain live, even though the main battery has been disconnected.
If you have information that this is, or is not the case please let me know and I will add it to the page. thank you. At some point I will do a trial on my own car, lofty.

On the side of the remote key there is a number, you are advised to record this in you owners handbook for reference purposes.
Both keys issued to a Mercedes Vehicle will be the same number.

If you have problems with your IR smart key or you have mechanically damaged the key you might like to visit this site where they claim to be able to replace /repair your key's

IR Smart key problems you might like to investigate this link.

I have not has cause to use them but it all sounds promising.

Central locking
I cannot answer questions for W169 models manufactured pre 09 However from 2009 and possibly before that date the car is fitted with electrical central locking and not a vacuum operated system as with the W168
From what information I have the SAM unit which I take to be the main control unit of the system is said to be located in the passenger foot well, as with the relay board see page.7.169 for more detail as to location

In addition each door has its own electrical actuator, the drivers main actuator being in the drivers door. If you have problems with the central locking you are advised to seek professional help and the system is linked into the can-bus which also controls all electrical components. main components mentions are electric windows winding motors/mechanism, electric mirrors. from what I have read the system is highly complex.
the easiest way to confirm if your car is electric central locking is to check the fuel flap locking mechanism, if it is electric you will see the electric actuator instead of the yellow vacuum hose as with the w168.

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