Code 85 - Prom Error & Code 87 - EEPROM Error
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1993 Pontiac Bonneville, 1993 Oldsmobile Ninety-Eight, 1993 Oldsmobile Eighty-Eight, 1993 Buick Riviera, and 1993 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
Ensure all ECM connectors are fully inserted in socket. If okay, have ECM reprogrammed using appropriate equipment. If equipment is not available, have ECM serviced through dealership.