The restructuring is designed to centralise control of manufacturing and product development, and to cut overlapping engineering projects and improve efficiency.
GM Europe lost a higher than expected $116m (£64m) in the first quarter this year, almost double the loss in the previous year, and the company says it is in danger of missing its target of bringing this below $100m (£55m).
The announcement will also involve the promotion of Carl-Peter Forster, head of Opel, to chief operating officer of GM Europe. No job losses are expected as part of the plan.
GM's Detroit head office has been growing increasingly frustrated at the failure of the European operations to integrate manufacturing and share components between the operations. There has been particular criticism of Saab, which until recently insisted on developing vehicles and manufacturing processes outside the global systems.