-- Don't underestimate the power of a spilled cup of coffee.

A United Airlines flight from Chicago to Frankfurt, Germany, was diverted to Toronto this week after the pilot dumped a cup of coffee on the plane's communication's equipment. The unwanted liquid triggered a series of emergency codes, including one for a hijacking, according to Transport Canada, the agency that regulates transportation in Canada.

"With the help of their company dispatch staff, the flight crew was confirmed the problem to be a NAV(navigation)/communication issue and not a valid code 7500 (for a hijacking or unlawful interference)," Transport Canada said on its website.

Flight 940 initially was going to return to Chicago, but then diverted to Pearson International Airport in Toronto where it landed without incident around 10 p.m. Monday.

United had little to say about the coffee spill that led to the diversion, and did not acknowledge that the caffeinated beverage had anything to do with it.

"Our review of the communications issue encountered on flight 940 continues, so it's too soon to comment on any particulars that led to the captain's decision to divert," United spokesman Rahsaan Johnson said late Tuesday. "But important to note the crew did maintain contact with controllers, and the decision to divert to Toronto was the captain's."

The Boeing 777 had 255 passengers and crew aboard. United retrieved them from Toronto and took them back to Chicago where they were put on another plane to Frankfurt Tuesday afternoon.