What was found
PIT - FLT 843 - SHORTLY AFTER TAKEOFF, BETWEEN 2,000 TO 3,000 FEET, THE PRESSURIZATION SYSTEM FAILED IN THE AUTO MODE. FLIGHT RETURNED TO FIELD AT PIT AND LANDED WITHOUT FURTHER INCIDENT. NO EMERGENCY WAS DECLARED. MAINTENANCE REMOVED AND REPLACED THE CABIN PRESSURE CONTROLLER AND THE CABIN PRESSURE SELECTOR PANEL (P/N 711002-5). OPS TEST GOOD PER MM 21-31-00. (M)