DETROIT (Reuters) -- General Motors said on Thursday it will replace the 120-volt charging cords for most Chevrolet Volt plug-in hybrid cars.
The exchange affects all 2011 model plug-in electric hybrid Volts and some 2012 models, GM spokesman Randal Fox said.
He did not know the total number affected, but said it was fewer than the more than 11,000 Volts sold so far. The car sells for just under $40,000 before federal subsidies of $7,500.
Yahoo Autos first reported the swap, citing consumer complaints about overheating cords. However, Fox said the exchange was not to address overheating.
"It's just an effort to offer a more consistent charging experience," Fox said. "It's not a safety recall. It's more of a customer-satisfaction program.
"We made some enhancements to the design to add some durability and reliability," he said. For example, GM increased the cord's cable size to enhance durability, he said.
The National Highway Traffic Safety Administration opened an investigation on Nov. 25 into the safety of the Volt's battery pack after its own repeated tests uncovered fire risks.
The fires occurred after NHTSA crash tests or other tests where the car's lithium ion batteries were purposely damaged.
NHTSA closed its probe in January without finding any defects and expressed satisfaction with GM's fix to better protect the lithium-ion battery pack by adding steel reinforcements and other steps to prevent coolant fluid from leaking and triggering a fire.
Some felt the probe was unnecessary, but the Volt has received outsized attention despite its small sales totals as many Republicans have criticized the car's sales and the federal subsidies its buyers receive.
GM idled the Volt assembly plant in Michigan for five weeks due to weaker demand.
GM CEO Dan Akerson in January said the Volt got "disproportionate scrutiny" because it had become a surrogate for election-year politics and commentary on Obama administration policy.
GM has showcased the electric car as the centerpiece of efforts on fuel efficiency and cutting edge technology.
Volt owners will be notified of the exchange in the next few weeks and as they bring in their cars for the battery enhancement they will also receive the new cords, Fox said.
The new cords will not change recharging time and the exchange does not affect the 240-volt cords, he said.