What was found
DURING DEPARTURE, THE PRESSURIZATION CONTROLLER FAULT LIGHT ILLUMINATED. RAN CHECKLIST, AND THE FAULT LIGHT RESET THEN ILLUMINATED AGAIN AFTER A COUPLE MINUTES. RAN MANUAL PRESSURIZATION CHECKLIST. DIVERTED. LANDING UNEVENTFUL. INTERROGATED CDS IAW MM TASK 45-00-21-742-802 AND FOUND FAULT AFT OUTFLOW VALVE FAIL. COMPLIED WITH FIM TASK 21-30-00-810-803 PARAGRAPH 4A (1)THRU(5). REMOVED AND REPLACED THE OUTFLOW VALVE IAW MM TASKS 21-31-16-000-801 AND 21-31-16-400-801. PREFORMED FUNCTIONAL TEST OF PRESSURIZATION CONTROL IAW Q400 MM TASK 21-31-00-720-801. CHECK GOOD