How do you know that the BCM is not communicating? If it has a code for the anti-theft has set,then the BCM (which is in control of passlock) is talking. The U1000 code can set from electrical noise interference on the data lines going all around the car, this code should be disregarded unless it is the only code and it keeps reseting. I assume your car wont start now having the passlock code set.
Have you checked all the power and ground to the BCM also check all the rear hatch and shift lock circuits using these diagrams. If all there, replace BCM and reprogram VIN.