The automaker said the shutdowns, which start Monday, will also include assembly plants in Spring Hill, Tenn., Lordstown, Ohio, and Fairfax, Kansas.
The Chevrolet Impala, Buick Regal and Cadillac XTS are built on the flex line. The consolidated line at the Oshawa plant will not be affected.
GM said the stoppage is not expected to have any material impact on its full-year production plans in North America or its second-quarter or full-year financial results.
Two earthquakes caused widespread damage last week in parts of Kumamoto and surrounding communities on Kyushu, the southernmost of Japan’s four main islands.
Toyota Motor Corp. shut most of its vehicle production in Japan because of parts shortages stemming from the earthquakes. Nissan Motor Corp. and Honda Motor Co. also temporarily halted production at some facilities.