I have a strange problem:
Try to start the car with the key usually used, won't start. Put in our
backup key, starts fine. Turn car off, put backup key 30 feet away, come
back and can start car with first key. Turn off car, come back later
(say 10 minutes) and first key won't start car again.

My understanding is that a coil around the ignition tumbler transmits
energy to a "chip" in the key which answers back with an ID code. This
enables the EWS system to start the car. Once it starts, I THINK a new
code is sent from the car to the key for storage till the next start. If
that is true, how come it won't start the first time, but will after
using the second key ?

This all started during troubleshooting a trunk closing problem. I had
unhooked the battery several times and the A1 module. I don't know if
this is related or a coincidence, but there is no other issues with the
car I know of. I have seen a programming sequence for the remote on the
keys, but wonder if there is a similar intialization routine for the
chip in the key.

I would imagine this same system is used in all the BMW of this vintage.

Thanks for your help.
--
Jim Collins
Sammamish, WA