2001 GMC Van B1000 B1001 B1004 B1007 B1009 U1300 U1000 Fault Codes After 4L60-E Transmission Replacement

I recently completed the installation of a remanufactured 4L60-E transmission on my 2001 GMC Van B1000. Following the manufacturer's initial startup procedures, I added 6 quarts of transmission fluid. After placing the van in neutral and starting it, I ran the engine for 20 seconds before shutting it off and adding another 3 quarts of fluid. I repeated this start-up and neutral cycle to add the final 3 quarts. After completing the fluid fill process, I shifted through each gear (D, 3, 2, 1), holding each position for 5 seconds. When placed in 'D' with the rear wheels elevated on jack stands, the vehicle did not move — indicating a potential transmission or control issue. I then connected the Blue Driver scanner to the data connector and retrieved the following diagnostic codes: - B1000: ECU Malfunction - B1001: Option Configuration Error - B1004: Kam Reset - B1007: EEPROM Checksum Reset - B1009: EEPROM Checksum Reset - U1300: Class 2 Data Link Low - U1000: Class 2 Data Link Malfunction These codes suggest a communication issue between the Powertrain Control Module (PCM) and other vehicle systems. Notably, the battery was removed during the transmission removal and installation process — approximately 10 days ago. I am seeking advice on how to resolve these fault codes, especially since I have not found any specific troubleshooting steps in the past 24 hours of research. Any insights or recommended procedures would be greatly appreciated. Thank you, Ron