The latest flaw in the plane’s computer system was discovered by FAA pilots.
Boeing says it has finished with its updates to the flight-control software implicated in the crashes.
Boeing is updating an automated flight-control system that has been implicated in the two crashes involving the 737 Max.
Feature designed to warn pilots when a key sensor might be providing incorrect information.
Chairman and CEO Dennis Muilenburg took reporters’ questions for the first time since accidents involving the Boeing 737 Max in Indonesia and Ethiopia killed 346 people.
Boeing has about 4,600 unfilled orders for the 737 Max, which was involved in two recent fatal crashes.
The airline has been substituting different aircraft on 737 Max routes.
The planes have been grounded around the world since mid-March.
Under the self-certifying program, planemaker employees perform tests and inspections needed to win safety approvals, with the FAA overseeing their work.