The Japanese automaker also said it would recall about 260,000 RAV4 sport utility vehicles, Tacoma trucks and Lexus RX350 SUVs sold in the United States to address a separate issue.
The recall of the Prius, one of America's best-selling passenger cars and the top-selling vehicle in California, covers 1.9 million hybrids from the 2010 through 2014 model years. It involves about 1 million cars in Japan, about 700,000 in North America and the rest in Europe and other regions.
Toyota said it will update software in the electronic controls of the car.
The software's current settings could generate heat in some of the transistors in the car's circuits, damaging the parts. When this happens, warning lights on the dashboard activate. In rare circumstances, the hybrid system might shut down while the vehicle is being driven, creating a sudden stall.
The automaker said it knows of no accidents or injuries resulting from the problem.
In the other recalls, Toyota will update software on certain 2012 RAV4s, 2012-13 Tacomas and 2012-13 Lexus RX350 models to fix an electronic circuit condition that can cause the vehicle stability control, anti-lock brake and traction control functions to turn off intermittently.
Analysts said the size of the recalls reflects Toyota's reaction to past criticism that it didn't move fast enough in recent years to address sudden acceleration issues in 2009 and other problems in its cars.
"Toyota is trying to be more transparent and is more aggressive than other automakers with recalls. But it doesn't seem to be that big of a deterrent for consumers," said Jessica Caldwell, an analyst with the auto information company Edmunds.com Inc.
"I don't think there is that big of an impact from something like a software update," Caldwell said. "It is not a recall where there are crashes or people are dying."
Alec Gutierrez, an analyst at the auto information firm
"Instead, it seems as though this is another case of Toyota trying to stay ahead of the curve by proactively issuing a recall to ensure those that own a Prius would not be at risk," Gutierrez said.
"Although consumers continue to give Toyota the benefit of the doubt, with the competition today stronger than Toyota has ever seen, they need to keep a keen eye on their quality to ensure current owners and potential intenders don't begin to look elsewhere when it comes time to buy a new vehicle," he said.
Toyota recalled nearly 5.3 million vehicles in the U.S. last year, more than any other automaker, according to the
Overall, automakers recalled almost 22 million cars last year, NHTSA said. That was 34% higher than the previous year and the most since 30.8 million vehicles were recalled in 2004, according to the agency.
Toyota's latest recall comes as it is negotiating a settlement of a four-year federal criminal investigation into whether it properly reported to safety regulators complaints about incidents of sudden acceleration in its vehicles.
Toyota confirmed the talks.
"In the nearly four years since this inquiry began, we have made fundamental changes to become a more responsive and customer-focused organization, and we are committed to continued improvements," the company said.
The settlement could include a fine of as much as $1 billion.
The automaker did earn some kudos for its automotive prowess Wednesday.
Lexus was named the most reliable car brand in the 2014 J.D. Power & Associates Vehicle Dependability Study, which examines the reliability of cars three years into their life.
It was ranked the most dependable brand for the third consecutive year.
Vehicles produced by Toyota's luxury brand had just 68 problems for every 100 vehicles. That was almost half the average of 133 problems per 100 vehicles.
Toyota-branded cars also did well, logging 114 problems per 100 vehicles. It ranked sixth, along with two others, out of 31 brands.