 GM halted production for about one month at the Detroit / Hamtramck Assembly plant by mid June 2011 to complete some upgrades , including the installation of new tooling , equipment and overhead conveyor systems throughout the facility . These upgrades allowed GM to triple the rate of Volt production and prepared the plant for 2012 Volt and Ampera production . After the plant retooling , the production rate reached 150 units per day four days a week by August 2011 . The Volt plant was also down during January 2012 in preparation for building the California lower @-@ emission version . A four @-@ week shutdown due to slow sales took place between March and April 2012 . GM said it had around 3 @,@ 600 Volts in inventory and needed to reduce dealer inventories as production is expected to meet market demand . GM also extended the traditional two @-@ week summer vacation by an extra week at the Hamtramck plant . GM closed its Detroit @-@ Hamtramck plant from September 17 until October 15 , 2012 , affecting roughly 1 @,@ 500 workers on downtime while the plant was retooled to assemble the all @-@ new 2014 Chevrolet Impala alongside the 2013 Volt . This was the second time in 2012 that GM has halted Volt production . 
