Ford Motor Co. has temporarily halted production and stopped shipments of its hot-selling F-150 Lightning electric pickup truck over an unidentified problem with its battery.

The automaker confirmed Tuesday it stopped building the plug-in pickup at its factory in Dearborn, Michigan, while engineers seek a solution to a “potential quality issue” discovered on a truck at the plant. Ford said in an emailed statement that it’s not delivering trucks that are in transit to dealers.

Demand for the Lightning has been strong since Ford began selling the battery-powered model of the best-selling vehicle in America last April. It helped the company more than double EV sales last year, making it the No. 2 seller of EVs in America behind Tesla Inc., which controls nearly two-thirds of the U.S. market.

Ford has been running the Lightning factory on three work crews, seven days a week with a goal of boosting output to 150,000 annually by the fall of this year.

Ford’s shares fell 1.3 per cent at 1:44 p.m. in New York. The production halt was reported earlier by Motor Authority.