What was found
THE PRESSURIZATION AUTO FAIL LIGHT CAME ON IN FLIGHT. RAN QRH AND THE LIGHT EXTINGUISHED, WHEN ALTERNATE WAS SELECTED. ACFT GROUNDED. ACCOMPLISHED FIM 21-31, TASK 801 DCPC BITE, NR 2 FAULTED OFV LRU FAILED, NR 1 NO FAULTS. DUE TO ACFT HISTORY, REMOVED AND REPLACED THE OUTFLOW VALVE ASSY IAW AMM 21-31-03. INSTALL TEST FAILED. NR 1 PRESSURE CONTROLLER SHOWS OFV LRU FAIL FAULT CODE 009 AS ACTIVE FAULT. COMPLETED FIM 21-31, TASK 802. REMOVED AND REPLACED THE OUTFLOW VALVE. OPS CHECKED NORMAL. NO FAULTS NOTED. GROUND VERIFICATION SUCCESSFUL.