The twin-engine aircraft, a Dash 8 plane, had one engine that wasn't working and it had hydraulic problems, Peel police Const. Thomas Ruttan told CBC News.
Ruttan said a call came into emergency officials at 2:54 p.m. ET, and the plane landed almost an hour and a half later, shortly before 4:30 p.m. ET.
The flight was operating as an Air Canada Express flight and was originally scheduled to land at the Billy Bishop Toronto City Airport.
A spokesperson for Sky Regional Airlines, which was operating the flight, said the journey began in Moncton, with a stop in Montreal.
The aircraft was orginally scheduled to land at the Billy Bishop Airport in downtown Toronto, but was diverted to Pearson as a precaution.
Sky says it is conducting an investigation to find out what went wrong with the engine.