Bolt chief engineer Jesse Ortega said dealers will install software that limits charging to 90% of the battery’s capacity until a permanent fix is developed.
The recall involved bolts from model years 2017 to 2019, including nearly 51,000 in the United States.
It comes a month after the United States’ National Highway Traffic Safety Administration announced it was investigating. The agency said in documents filed last month that the fires started under the back seat as the cars were parked and unattended.
Ortega said engineers traced the fires back to Bolts with battery cells made at an LG Chem factory in Ochang, South Korea, from May 2016 to May 2019. The fires occurred while the batteries were about to be fully charged, he said.
“We have no confirmed incidents of vehicles with cells not produced at this plant or in a lower state of charge,” Ortega said.
Certain 2019 Bolts and all 2020 and 2021 versions have cells made at an LG Chem plant in the Netherlands, Michigan, and were not included in the recall, he said.
GM was hoping to find the cause and have permanent repair as soon as possible after the first of the year, Ortega said. Engineers have studied several potential causes and do not have a dominant theory, he told reporters on a conference call Friday.
Until software updates can be made, GM is asking owners to manually change adjustable settings to prevent batteries from being fully charged. Homeowners who are unable to do so should park their bolts outside and contact a dealer, Ortega said.
The company said it would immediately begin notifying dealers and customers of the tentative recall.
Ortega said GM noticed the fires and started investigating in July, and was cooperating with the NHTSA investigation.
Changing the software will reduce the Bolt’s range by about 10% on a single charge. GM said it understands owners might be upset that their cars are not fully functional and will deal with complaints on a case-by-case basis. Older Bolts have a range of around 238 miles per charge.
The National Transportation Safety Board, a federal agency that investigates transportation-related issues, is investigating electric vehicle fires and a report is expected shortly.