US Closes Chevy Volt Safety Probe, Says Car Is Safe

(The Wall Street Journal) - The National Highway Traffic Safety Administration on Friday closed a safety investigation into General Motors Co.'s battery-powered Chevrolet Volt without taking action, saying it found no reason to believe the car poses an unusual risk of fire.

"The agency's investigation has concluded that no discernible defect trend exists and that the vehicle modifications recently developed by General Motors reduce the potential for battery intrusion resulting from side impacts," NHTSA said in a statement.

In November, US auto safety officials started an investigation centered on the Volt's lithium-ion battery pack after batteries in three vehicles sparked or caught fire days or weeks after being severely damaged in crash tests.

GM will make repairs to the roughly 12,500 Volts either on the road or on dealer lots and will incorporate the fixes into vehicles it will begin building in February.

Friday's announcement caps a two-month probe that had threatened the vehicle's image and sales of the high-profile car. GM maintained the car is safe but took unprecedented steps to reassure Volt owners and the public that it was taking the matter seriously, including repurchasing some vehicles.

"NHTSA's decision to close their investigation is consistent with the results of our internal testing and assessment," the company said in a statement. Referring to measures it is taking to reinforce the vehicle and prevent coolant leaks, GM said the moves are "intended to make a safe vehicle even safer."

GM had said at the time that a coolant leak occurred when the car was damaged, causing the chemical to eventually crystallize and creating an electrical short circuit.

NHTSA's investigation was unusual in that the fire and spark incidents did not happen in real-world driving and could not be replicated in tests. The first fire occurred in a Volt that was stored on NHTSA property weeks after the car was severely damaged in a crash test. Subsequent incidents happened after batteries were removed from the vehicles, directly damaged, then left to sit.

NHTSA, in its statement, acknowledged the Volt investigation was not typical but that it took unusual steps because the Volt involves technology new to the auto industry.