(August 28, 2012) DETROIT — General Motors plans to idle the plant where it assembles the Chevrolet Volt plug-in hybrid for four weeks starting next month, two people familiar with the plans said.

GM will close its Detroit-Hamtramck plant from Sept. 17 until Oct. 15, one of the sources said. Union representatives last week told the plant's roughly 1,500 workers about the scheduled downtime, the source said.

GM also notified suppliers last week, according to another source in the supply chain. A GM spokesman wouldn't confirm whether the company planned to idle the plant.

"We don't comment on production schedules," the spokesman said. "We continue to match supply and demand."

It's the second time this year that GM has throttled back on Volt production. The Detroit-Hamtramck plant was idled from March 19 until April 16 amid swollen Volt inventories.

Volt demand has picked up this year, after sales last year fell short of GM's goals. GM sold 10,666 Volts through July, more than triple the 2,870 sold during the same period a year earlier.

GM executives have attributed the sales increase to strong demand for a low-emissions version of the Volt that qualifies for California's coveted carpool lanes, which GM launched in March. Previous versions of the Volt didn't qualify.

Volt inventories have been whittled down, too, to 6,500 units, or 84 days' worth, as of Aug. 1. On March 1, just before the last production shutdown, GM had 154 days' worth.

Source: Automotive News