GM makes high-voltage move, calls back all Volts for potential battery fires

Arguably biggest setback for hybrid and electric cars has been announced with General Motors' revelation that it's "calling back" all Chevrolet Volts sold in the United States as a precaution against battery pack fires.

The call back involves about 8,000 vehicles, with the carmaker detailing it needs to "toughen the protection around the battery pack and make other changes to prevent fires following a crash."

Sales of the Chevy Volt began U.S. markets in mid-December 2010.

GM executives said while the changes came following a federal probe into three fires in Volt battery packs after crash tests, they had seen no complaints from customers, no disparaging reports from Volt owners on the road and no sign of fire in its own crash testing.

The announcement — which GM calls a "customer service campaign" — will involve adding steel plates around the battery pack, adding a sensor to watch coolant levels for the battery's temperature controls and a new cap to prevent coolant overfilling. The fixes will take about two hours at a dealership.

GM representatives said 250 Volt customers requested either a loaner or for GM to buy back their Volt following the federal probe.

Since the repair offered by GM does not qualify as an official federal safety recall, it can continue selling Volts while it makes the parts for the repair, which it expects to have by late February.

In November, the National Highway Traffic Safety Administration (NHTSA) revealed a Volt battery pack had smoked and caught fire more than three weeks after a side-impact test where the car had been smashed into a pole at 20 mph. At the time, GM had said the agency had not followed the automaker's procedures for discharging the battery following a crash, and had it done so, there would have been no fire.

NHTSA later said it had recorded two more fires after simulated crash tests on three of the Volt's 390-lb.lithium-ion battery packs, rupturing their coolant lines and damaging their outer compartments.

GM has also faced questions about the Volt's 120-volt charging cord, after several customers reported the cords had overheated or even melted while charging. GM has said the cords were safe, but has been replacing them for free if owners complain.