DTC B1007: Checksum Value Error: Description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2002 GMC Savana, 2002 Chevrolet Chevy Express, 2001 GMC Savana Special, 2001 GMC Savana Camper Special, and 2001 GMC Savana. However, it is still accessible from the selected car via links, so may be relevant.
Passlock(tm) module calculates a checksum for contents of EEPROM when voltage is first applied. This calculated checksum is compared with checksum value stored in EEPROM. A history DTC will clear after 100 consecutive ignition cycles occur without a fault. Use Scan Tool to clear history and current.