I have lost my yesterday. So I went to my service center , they cancel the key for me and told me that the key cannot start the car engine but can unlock the car doors. Will the alarm system work when someone use the key? Should I change my key?

I would change the keys.
The lost key will unlock the car and disable the alarm if used...

I thought the dealer could reprogram the immobiliser to recognise/not recognise a key chip. Clearly the locks are mechanical, so will keep opening, but the engine should not start, and the alarm should not stop, surely?

:think:

Having said that, anything you have in the car is not safe as the key will open the door.

For some reason BMWs alarm deactivates if the doors are unlocked it doesnt matter if the car is reporgrammed to "forget" about the lost key.

There have been TONS of reports of thieves jamming a screwdriver into the door lock and just turning the screwdriver... that will unlock the door and disable the alarm only thing the scrwe driver wont do is start the car.

Oh great did I just give out too much info too dangerous for the net? If anyone thinks so please report it to the admins and have this post edited or deleted.

No, I don't think you have. Also, it seems that - like practically everything else on BMW - the alarm behaviour changes by national version. In the UK having the door unlocked - with the key - will not prevent the alarm from sounding. Quite the opposite. The alarm will shut up only when the key is recognised by the immobiliser (i.e. the engine is started).

TBH - the US alarm behaviour seems a bit self-defeating...

sorry to hear this, get a new set of keys and reprogram the other keys, it will cost you lots. :doh:
I alway hook my key to my jeans and put it 1 place in the house. cost too much to loss.

I dont think This is correct. I had a go with my spare key, and the alarm came on when i pulled the dorhandle.

Now this was te little black key, but nevertheless, the alarm came to life, and it was loud too. :P

Well if thats the case then thats good. but if you search around I've read at least couple reports of people having their car broken in with a screwdriver. couple E39s and at least 1 E60.

Your valet key should have deactivated the alarm... maybe your dealer had the option set for your car that if you unlock the doors physically with the key it'll sound the alarm... there is that option. It seems like most cars in the US has the alarm set to turn off when you use a physical key to unlock.


Ok heres some links to the reports I've seen for those that put doubt to what I say.

Post 2. I know of several reports of this happenning in new jersey just like poster number 2 indicated.
http://www.m5board.com/vbulletin/showthread.php?t=77067

Check out this thread and post #21.
http://www.m5board.com/vbulletin/showthread.php?t=70742

Some E39 reports.

http://www.m5board.com/vbulletin/showthread.php?t=26266

http://www.m5board.com/vbulletin/showthread.php?t=25354


Ok thats enough proof for now. I'm sleepy.

No proof was needed. :thumbsup:

In the manual it says clearly that alarm behaviour will vary in certain markets (to be precise, it says "in some national versions, the alarm can only be deactivated with the remote control" or something like that). Now we know what it means. I remain of the opinion that having an alarm that shuts off when a door is opened is less than useful, but chacun a son gout.

:rolleyes: :thumbsup: Thanks for all of you, very helpful for me ...Love you all....