Lockout issue Key battery died?

Tiny
KAGE2927
  • MEMBER
  • 2010 BMW 328
  • 3.0L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
So I am locked out completely. Key battery died. I fixed that. Went and locked the car with the remote for the first time and I heard all 4 doors actuate but none of them unlock. I heard the gas tank door lock and unlock as well. That does release. Trunk will not open.

Here is the real kicker. The door key is not the one for the car. It was hit previously and did the previous owner did some DYI repairs. New fender and front suspension. I believe the replaced the door as well since the rescue key does not open the door that is on the car.

I am having a lock smith come out but I cannot find ANY wiring diagrams for the BCM to check wiring and continuity hitting the proper levels.

I would normally say its a door actuator but the liklihood that all 4 actuators are bad is slim but never 0. If there are any diagrams you guys can provide I would be greatly appreciative of it.
Thursday, December 25th, 2025 AT 2:44 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,831 POSTS
To me it sounds like the main 12 volt battery is bad in the car. I would also do a CAN scan to see if any codes are stored.

CAN SCAN - https://youtu.be/u-4syLc-ifQ

On E90 the central locking fuses 72 and 73 are commonly referenced for lock issues so I would check those. So the BCNM is called the footwell module, here are the wiring diagrams for it. Check out the images (below). Please let us know what happens.

Was this
answer
helpful?
Yes
No
Friday, December 26th, 2025 AT 9:55 AM

Please login or register to post a reply.