GM assembles the Volt and recently began making small numbers of the redesigned 2013 Chevrolet Malibu at the Detroit-Hamtramck plant, which straddles both cities' limits. GM assembled 590 Malibus in June and July, according to the Automotive News Data Center.
Most Malibu production is done at GM's Fairfax assembly plant in Kansas City, Kan.
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.
Tracking EV sales
Volt sales have been a closely watched barometer of demand for electrified vehicles, as several other automakers are in various stages of rolling out electric and plug-in hybrid vehicles. The Volt also has become a target of conservatives who criticize the Obama administration's financial support for green-car technology.
GM has said it plans to add a second shift to the Detroit-Hamtramck plant once it starts production of the next-generation Chevrolet Impala sedan there. GM is expected to begin making the redesigned Impala at the plant during the first quarter of 2013.
James B. Treece contributed to this report