"The software calibration for the fuel cutoff functionality in the engine control module is too sensitive," the NHTSA said on its website. "Sudden engine stall could occur, increasing the risk of a crash."
Volvo explains that the problem occurs when the driver is braking during city driving and/or releases the accelerator pedal.
"The engine idle speed may drop, resulting in a sudden engine stall without any prior warning," the automaker said in a statement. "If this condition occurs, the transmission control unit will enter a temporary protection mode in order to prevent damage to the vehicle's transmission. When starting the vehicle again, the driver can operate the vehicle safely home or to an authorized Volvo repair facility, but may experience a louder than usual transmission and a harder gear engagement."
The remedy involves a simple software upgrade to the engine and transmission electronic control modules. This is a free service that will be performance at Volvo dealerships.