Toyota Motor Corp. resumed full production at all North American plants this week and said it will expand U.S. output of small engines as Japan’s largest automaker works to boost sales slowed by a March earthquake, according to Bloomberg.

As of this week, “all plants and suppliers in North America are at full speed, and most are working overtime,” Steve St. Angelo, executive vice president for North American engineering and manufacturing, told reporters yesterday in Torrance, California. “Our parts problems are now behind us.”

Toyota will also add production of four-cylinder engines at its plant in Huntsville, Alabama, St. Angelo said. The company will hire 240 more workers at the factory, which already makes six- and eight-cylinder engines for Toyota models built in the region, he said. Four-cylinder output will start late this month, said Mike Goss, a Toyota spokesman.

The company briefly halted production after Japan’s record earthquake and tsunami in March and lost sales in markets including the U.S. as reduced supplies of parts and power in Japan led to vehicle shortages. Through August, the Toyota City, Japan-based automaker’s U.S. sales fell 7.8 percent as the industrywide total rose 10.5 percent.

Toyota already makes four-cylinder engines in Georgetown, Kentucky, and Buffalo, West Virginia. The added production will be for Corollas to be built at the company’s Blue Springs, Mississippi, plant, which opens in November, St. Angelo said in an interview yesterday at the company’s U.S. museum in Torrance.

Production of the 2012 Camry that goes on sale this week is accelerating at the Georgetown plant, the company’s largest in North America, said St. Angelo, who joined Toyota in 2005 after working for the former General Motors Corp. for 30 years.

Toyota’s U.S. sales unit is also based in Torrance. The company’s American depositary receipts, each representing two ordinary shares, rose 88 cents, or 1.3 percent, to $69.05 yesterday in New York Stock Exchange composite trading.