General Motors Co. stated on Thursday that it is restarting production at a handful of factories that were previously idled because of a global shortage of semiconductors.The Detroit-based automaker plans to resume some production at a factory in Michigan next month, after halting work at the facility in early May. It also plans to restart several auto factories in Canada, Mexico, and South Korea within the next several weeks that make models such as the Chevrolet Equinox and GMC Terrain crossover vehicles. Despite the reopening of these facilities, GM Chief Executive Mary Barra has stated that the company expects the second quarter to be the auto maker’s weakest of 2021 in terms of reduced production before some recovery takes place in the back half of the year. The computer-chip shortage continues to cloud an otherwise strong new-vehicle market, over a year after the Covid-19 health crisis led to a collapse in US auto sales and production last spring.