????Since introducing its Camry family sedan in 1983, Toyota Motor Corp. has brought out an all-new version of the model every five or six years, making slighter modifications and enhancements in the interim.

????This time, Toyota is accelerating the pace of change. Just three years after the seventh generation Camry was introduced, Toyota is revamping the car extensively, in keeping with an exhortation from CEO Akio Toyoda to “make better cars.” While not quite a complete makeover, Toyota has replaced about a third of the Camry’s 6,000 parts and restyled the exterior and interior to make it more eye-catching and less bland.

????Though Toyota won’t disclose how much it invested, the sum is likely in the neighborhood of $500 million, an unexpectedly large investment to keep Camry at the front of a pack of midsize sedans that includes Honda Accord, Nissan Altima, Chevrolet Malibu, Hyundai Sonata and Ford Fusion.

????“The midsize family sedan segment is three million units a year,” said Bill Fay, group vice president of Toyota’s U.S. sales organization. “It’s still the biggest segment in the U.S. market and very important to us.”

????Twelve years running Camry has been the No. 1 best-selling car in the U.S. In 2014 it leads the segment again and likely will reign as top-seller for a thirteenth year in a row. Toyota’s decision to invest half a billion dollars in Camry just two years ahead of its likely next full-model change is an aggressive move, difficult to justify on financial grounds alone, yet reflective of the automaker’s determination not to cede leadership.

????Last April, at the New York Auto Show when the Camry prototype was unveiled, Fay said Toyota knew the car had to be far more visually expressive to compete with bolder styling from Ford’s new Fusion and Hyundai’s new Sonata. The midsize family segment also faces new competition from lower-priced sedans by Mercedes-Benz and other luxury manufacturers.

????The most noticeable styling change is Camry’s new fascia, which is bold, open and forceful, like a mouth about to devour whatever is in front of it. Except for the roof, the entire exterior is new. Toyota engineers also added to the rigidity of the car’s body with more spot welds, as well as more insulation to make the cabin quieter.

????Following Akio Toyoda’s ascension to chief executive in 2009 in the midst of the automaker’s sudden-acceleration troubles, his mandate to subordinates was clear: shake up the company and improve the products. Among the organizational changes in the U.S. is a move for the company’s headquarters to Plano, Texas from Torrance, California.

????Toyota’s impressive financial strength gives it the latitude to embark on a costly mid-cycle upgrade for a key model like Camry. The goal isn’t just to sell more cars and at higher prices: Executives know Volkswagen AG and General Motors are gunning for Toyota’s title of No. 1 globally in sales.

????The new Camry symbolizes Toyota’s determination to maintain a lofty status with consumers, reviewers, credit ratings agencies and others who assigned high grades to the company’s vehicles and financial performance

????That won’t be easy: As many big, successful companies have discovered, complacency can be the subtlest and deadliest of enemies.