NEW YORK (CNN/Money) -
A software problem is causing some Toyota Prius gas-electric hybrid cars to stall or shut down while driving at highway speeds, according to a published report.
The Wall Street Journal reports that the problem involves Priuses from the 2004 model year and some early 2005 models.
The newspaper reports the National Highway Traffic Safety Administration has logged 13 reports of the engine shutdowns, while Edmunds.com, a popular vehicle-information and shopping site, has had 13 individuals post complaints in a Prius forum. Some of the cars that shut down had to be towed to the shop before they could be restarted.
The newspaper quotes an official from Toyota as saying the stalling problem is due to a software glitch in its sophisticated computer system.
The car has both a gasoline engine and an electric motor, which is set to provide it with power during certain driving conditions, particularly in city driving. The gasoline engine is supposed to be shut down or run at a very low level when the car is driving slowly or idling but provide most of the car's power when it is cruising at highway speeds.
The report said no injuries or fatalities have been linked to the problem, but it did not say whether there had been accidents due to the problem.
A NHTSA spokesman said the agency is monitoring the complaints, but no formal investigation has been initiated.
Toyota spokesman Sam Butto told the newspaper the auto manufacturer identified a "programming error" in the computer systems of 23,900 Prius cars last year and sent owners a service notice advising them to bring the cars into dealers for an hour-long software upgrade.
He couldn't say how many Prius owners got the upgrade and whether the latest problems involve buyers who never got the upgrade or if an altogether different glitch is shutting the car down.
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