American Airlines Fight 47 landed at O'Hare at about 4 p.m. from the London Heathrow Airport.
Shortly after landing, crew reported a "engine issue," according to the FAA.
All passengers deplaned the Boeing 787-900 at Terminal 5, the FAA added.
The Chicago Fire Department responded to the call, the Chicago Department of Aviation said.
American Airlines has not released more information.
CDA said there was no significant impact on airport operations.