As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BUF - FL 303, FLIGHT RETURNED TO BUF DUE TO PRESSURIZATION FAULT AT 8,000 FEET. NO EMERGENCY WAS DECLARED AND THE FLIGHT LANDED WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED THE PRESSURE CONTROLLER AND THE AFT OUTFLOW VALVE. OPERATIONAL CHECK GOOD. REFERENCE USAASB97010.