Hi all, Hoping someone can give me a quick 'how-to' fix on this. Got a 2004 Z4 and recently bought a second proper key off BMW dealer. Anyone know how I can code it to unlock the car? Tried following various youtube guides. Problem is, if I code the new key to work, then the old one in my other pocket seems to stop working. Solution I'm looking for is how to code both keys to work, rather than one negating the other. Hope that makes sense. Obvious answers (Don't let anyone else drive it, throw away the other key. Take it back to dealer, look like total idiot) both discounted already unfortunately due to life and stubborness. Cheers!