What was found
ON CLIMB OUT PASSING APRROX 8000' OUT OF DFW WE GOT AN AUTO FAIL CABIN PRESSURE LIGHT WITH THE CABIN PRESSURE SWITCH IN ACT, PER MEL 21-14C. MAINTAINING CABIN PRESSURIZATION IN MANUAL MODE WORKED FINE. GROUNDED-YES. ACCOMPLISHED NR 2 DCPC BITE, REF B37-900 FIM 21-31 TASK 801. FAULT CODE 069 'OFV LRU FAIL' LOGGED. SYSTEM TEST DCPC NR 2 PASSES AND FAULT CLEARS ON GROUND. REMOVED AND REPLACED AFT OUT FLOW VALVE ASSEMBLY, IN REF TO B737-900 AMM 21-31-03, OPERATIONS CHECK NORMAL. PERFORMED TEST OF MANUAL MODE AND CABIN PRESSURE CONTROL SYSTEM, OPERATIONS CHECK GOOD, IN REF TO B37-900 AMM 21-31-00710-801 AND 21-31-00-700-802.