Hey buddy were you able to figure this out? Im in the same boat bought the car used which only came with one key so I bought a new flip key off of amazon, got it cut, but cant seem to program it. I can unlock and lock the doors manually with it and it beeps and all and can even but the key in the ignition and turn it but the key warning light comes on the dash which I am assuming means it isn't programed.

 

The local shop actually had a Zed programmer(big bux and really awesome) Unfortunately, my build date was just old enough that they would have had to pull the security module from my car and wire it up to the programmer. The newer models can do it from the ODB2 port though. mines a 2010 e60

 

Sorry to revive an old thread but I wanted to add some information.

Programming a key to your BMW's CAS will cost you money, regardless if you DIY or pay someone to do it. The tools for you to DIY will be in the $200 range for Chinese clones and the process takes 15 min.

1: It's FAR easier to program a virgin key than a 'used key'. Virgin comfort access and non comfort access keys are $15 USD on Aliexpress.

2: A used key will need to either have the transponder de-soldered and a new one soldered in ($4 per transponder chip) OR you can purchase a PCF79xx Unlocker, or Xhorse VVDI PROG Programmer, and fiddle around with that to erase the data from the transponder. As you can see, you're better off buying a virgin key!!!

3: You can use HiTag2 to prepare a blank key and create the file for use in BMW Explorer/EF Scanner.

4: With a battery tender/charger on your car, use EF Scanner to program the new key to the CAS.

5: If you're on a budget you can get your key blade cut/copied at a local lock smith for ~$15 USD... otherwise you can buy a Defu 368a key cutting machine.

Here's how:

 

I've got a 2007 BMW 530i w/ comfort access...my circuit board was damaged, but the transponder is still in tact. My question is, if I were to buy an OEM blank could I have the original transponder soldered onto the new blank board and it work without any additional programming? I saw it briefly mentioned earlier, I just wanted to confirm..before I went to the dealer.

 

Check out the guy who runs Roskinc.com
He may have a solution for you.

 

The transponder will allow your car to start... But in order for the fob to lock and unlock doors you will still need to write the key into the CAS as the Key Id will be different and it will need to sync with the car (for those pesky handshake codes and all). At the end of the day its faster to just buy an $15 virgin fob from china and program it into the CAS and sync it with the car.