Boeing says it's delaying the delivery of 737 jets and is planning to inspect some already in service.
The Chicago-based company says the planes have parts that don't have a required coating to keep them from corroding. Those parts have to be replaced.
Boeing spokeswoman Vicki Ray says the uncoated parts have been in use since August 2007.
The company Web site says the parts were used in more than 390 planes delivered as recently as last month.
These parts attach wires to planes' fuselages. There are thousands in each jet.
Boeing says the parts don't pose an immediate flight safety risk.
Boeing was notified about the problem by Spirit AeroSystems Inc. The Wichita, Kan., company builds wing and fuselage components for nearly every Boeing commercial aircraft.