Originally Posted by MMME30W
Locking is done on a CA car either by pressing the 'lock' button on the fob, or resting a finger lightly on the ridged surface on the door handle until it locks.
I dunno if the car locks automatically. Be curious if anyone knows.
PS Owners manuals are available on www.bmwusa.com
under the Owner section.
You can set the car to lock automatically after a timeout via the iDrive. I wouldn't suggest it as its too easy for someone to walk up after you leave (don't know what the specific time frame is). I think that it's designed more to help if you walk off and forget to lock the door.
You should always lock the car with your door handle sensor.