reprogram key fob

i been having problems with unlocking my e46 with the stock built in alarm ever since I bought the car.

I press unlock once, driver side door opens, i press twice, the passenger side should open( 5/6 attempts and it does). it starting to piss me off.

anyways to reprogram the key fob manually? or any things to look out for?

Your problem lies in the passenger door, not the key.

EDIT: Unless the key battery is dying.

Well sometimes, the car would go, beep beep, and neither door would open. If I replace battery, would I need to reprogram key as well?

No. Just don't leave the key without a battery for more than 60s or it will lose it's rolling code position and you will have a little more trouble getting it to unlock the first time you use it.

Sounds to me like your lock motors are getting weary and may need cleaning and replacing. Do the battery first, since it is the cheapest fix.

Sounds like a pain in the ass if you ask me. Cutting a key open and glueing it together

not too hard actually pretty easy I just need to order a battery replacement

Also: what type of key do you have? Replacing the battery on the earlier style (rectangle not diamond) is easy.

OP, what year is your car?

Also it could be a dying relay in the GM5.

http://www.bmwgm5.com/

I have an 00'. It looks like an oval shaped triangle.