Originally Posted by Dackelone
Noop! The way I understand it... all BMW's can "learn" up to TEN key fobs from the factory. IF you loose a key fob... your dealer just add's another new key fob into the car's "directory".
What I was told is that the dealer or a knowledgeable "car coder" can "lock" the DME to just the current two key fobs. Then IF someone tries to clone a new key fob into the car's DME the car will not except the new fob - and the car can not be stolen that way.
As far as I know... BMW's SW update "patch" is ONLY for UK cars. I hope they roll it out to every bmw market though.
DME has nothing to do with the key's.
DME controls the motor only, and verifies a special code with CAS before fuel injection is activated. If key is wrong, CAS will not pass the correct code to the DME and therefore car will not start. If key is wrong, CAS will not authenticate and ignition will not turn on.
You can have a bunch of keys, and even when disabling keys 3-10, if the thief has a tool to sync another key they can steal the car. With the right tool it's not hard on a car with software before 47.1.
BMW's 47.1 update is for all cars, although this issue seems most prominent in the UK, and BMW haven't said anything here in the US probably to avoid panic. I have updated quite a few cars here with the security update.