Nissan Motor Co., Japan's second-largest automaker, is investigating reports from buyers that its new Leaf electric car occasionally fails to restart after being shut down.

Nissan has received reports from "several" drivers in Japan and the U.S. who were unable to turn their battery-powered cars back on, Toshitake Inoshita, a company spokesman, said Monday. The Yokohama-based carmaker said the problem may be related to an air conditioning system sensor.

The potential glitch compounds problems for Nissan as it tries to meet U.S. demand for Leaf hatchbacks that were already being delivered at a slow pace before the record earthquake and tsunami on March 11 further slowed production. Nissan said last year it had a waiting list of 20,000 U.S. buyers for the car. The company delivered 471 from late December through March and hasn't said when all orders will be met.