General Motors Co. will suspend production of the Chevrolet Volt for an extra week this summer as it tries to control the electric car’s inventory.

But the company says sales picked up in March to a record of more than 2,000, and it may cancel the extra week closing if sales stay strong.

Most auto factories close for two weeks starting in early July to get updated for the new model year. GM added a third week at the Volt factory that straddles the border between Detroit and the small enclave of Hamtramck. GM has already shut the plant from March 19 through April 23, as the supply of Volts grew on dealer lots. About 1,300 workers at the factory have been idled.