Chevrolet is asking owners of about 4,000 Volt plug-in hybrids from the 2013 model year to bring their cars to dealers for a software upgrade. Michelle Malcho, a spokeswoman for General Motors, said in a telephone interview the upgrade was necessary to ensure the Volt would avoid losing power when in motion.

Ms. Malcho said the problem involved a delayed-charging function: a feature that allows owners to preselect a convenient time to charge the Volt’s batteries when electrical rates are low, for example.