Mazda Names New Head of U.S. Unit : Management: Kazuo Sonoguchi replaces a president appointed two weeks ago who withdrew for medical reasons.

Mazda Motor Corp. in Japan has selected Kazuo (Sonny) Sonoguchi to serve as president of its Mazda Motor of America subsidiary here.

Toshio Wakiya, appointed to the same post two weeks ago, withdrew because of what Mazda officials termed an “unforeseen medical condition.” No other details were made available. Wakiya, 51, will remain in Hiroshima, where Mazda Motor Corp. is based, and continue as general manager of the company’s North American marketing and sales division. The 28-year Mazda veteran also remains a member of the auto maker’s board of directors.

Sonoguchi had just been appointed deputy general manager of Mazda Motor Corp.’s parts and accessories sales division and was preparing to leave Irvine for Japan to take that post when Wakiya gave up the Mazda Motor of America presidency.

Mazda Motor of America has 1,300 employees, 840 of whom work in Irvine.

Since 1990, Sonoguchi had served as a group vice president and deputy general manager of Mazda Motor of America, the company’s U.S. import, distribution and marketing arm.

Before that, he served for three years as vice president of corporate planning at Mazda Motor Manufacturing (USA) Inc., the automobile production facility in Flat Rock, Mich., where Mazda’s MX-6 and 626 models are built.

A 29-year veteran of Mazda, Sonoguchi has also served in the international business development and export planning offices at Mazda headquarters in Japan.

The appointments are part of Mazda’s policy of rotating overseas assignments for its top executives. Sonoguchi and Wakiya succeeded Yoshinori Taura, 53, who had been with Mazda Motor of America since it was established in 1988. Taura has returned to Japan for a new corporate assignment.