2002 Buick Rendezvous Error message

After working on the car I reconnected the battery. I now have in place of the odometer reading ,it reads error.
I have had trouble in the past with electrical, afted setting the door locks every thing electrical locked up. the car ran ,the speedodometer worked the headlights worked. No other lights or electrical worked. The radio read, security locked. I have reset it in past by disconnecting power and reconnecting power. Also the key fobs no longer work. Any ideas-BCM? If so how much to replace

thanks Les