Joseph S Holtsville , NY June 21, 2019 Appliance: Frigidaire Dishwasher PLD4375RFC0 Frigidaire Dishwasher Pld4375rfc0: Frigidaire error UO vent assembly issue. How to replace Vent Assembly (Air Duct). After a little research I discovered the UO error code usually means the vent assembly needs replacing. This is a great website and it made it easy for me to figure out what part was needed. Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes