"The brake-pedal stopper pad can deteriorate, allowing the stop-lamp switch plunger to remain extended when the brake pedal is released," NHTSA said in its recall summary. "The brake lights may stay illuminated, preventing accurate communication to rearward-following vehicles.
"Additionally, if the brake-switch plunger is not retracted, then the transmission can be shifted out of Park without depressing the brake pedal. Either condition increases the risk of a crash."
A Hyundai spokesman did not respond immediately to a query from Edmunds asking if there are any injuries, crashes or fatalities linked to the problem.
The affected Sonatas were built from December 11, 2009 to June 30, 2011.
Edmunds says: This recall will not begin for several weeks. If you have an immediate concern, it's best to contact your Hyundai dealer now.