DETROIT—General Motors is recalling more than 400,000 pickup trucks in the United States because the side air bags can explode without warning and spew parts into the cabin. The recall covers certain 2015 and 2016 Chevrolet and GMC Sierra 1500, 2500, and 3500 trucks. Documents posted Friday by U.S. safety regulators say the air bag inflator can rupture or the end cap can fly off on both sides of the trucks. Documents say three inflators ruptured in 2015 Silverados last month, one in Florida and two in Texas. All three trucks were unoccupied at the time, and GM says it has no reports of injuries. The company says a manufacturing defect allowed moisture into the inflator while it was being manufactured, causing corrosion. The inflators were made in Mexico by Joyson Safety Systems. Dealers will replace both side air bag modules. The company says it has a limited number of …