[3pointohhhh]

I need a second key replacement for my car. A wrecking yard has one used from a 2018 M550i just like mine. Can someone point me in the right direction for how to program key to work with my car? TIA

[Joe-BMW33]

Originally Posted by 3pointohhhh

I need a second key replacement for my car. A wrecking yard has one used from a 2018 M550i just like mine. Can someone point me in the right direction for how to program key to work with my car? TIA

No-can-do. Have to get one from the dealer/Germany.

[3pointohhhh]

Really? Ok thanks for the update.

[Qsilver7]

What would be the purpose of an encrypted key that only communicates with modules that have the same encryption to prevent theft…if all you had to do is buy a used key and do some simple initialization to make it work?

The earlier iterations of BMW key encryption has been cracked with the use of the AK90…but it still requires retrieving the encryption key from the DME or EWS control module. Then when BMW went to the CAS module…the encryption got longer and more modules have been included in the system.

The remote fob is not just a one trick pony. It has multiple things going on. One is the immobilizing feature that shuts down ignition and fuel if certain modules and the remote con’t communicate the same encryption. It operates on a 125 KHz radio frequency and is self powered through induction…it doesn’t require the battery inside the key to operate. So if the remote fobs battery is dead…you can hold the remote next to the ring antenna in the steering column…and the engine will still start.

Then you have the central locking system…which operates on a 315 MHz radio frequency in the US. Its signal is picked up by an antenna in older BMWs and now I think it is picked up by multiple antennas around the vehicle. And now…also with CA (comfort access) where you can touch a door handle and the vehicle unlocks…as well as the latest proximity sensors where the vehicle will unlock and lock as you walk up to or away from the vehicle.

The CAS module also has 10 spaces total for sets of remotes. These encrypted spaces in the module are held in a database by BMW…that is why most people will tell you to just buckle up and order a new key from BMW. There may be some people that have cracked the system and actually know how to retrieve the encryption key and then write it to a new transponder and then add that info to your CAS module…but I would recommend understanding completely what is required and make sure the person that says they can get a used key to work…know what all is required so that you don’t end up with a semi expensive paper weight…whose cost could have gone to paying for a remote fob from BMW that will actually work.

Hope this brings clarity to BMW remote fob’s complexity.