The National Highway Traffic Safety Administration said Monday on its website that it had received one complaint alleging complete steering loss. The preliminary investigation covers more than 50,000 vehicles.
The complaint said the steering shaft detached from the steering wheel, leading to a complete loss of steering, and the shaft fell into a position that interfered with the driver's ability to brake.
The government agency seldom opens an investigation based on one complaint but said it was "very concerned about this failure in that it occurred without warning on a new vehicle at low mileage and resulted in a complete loss of steering as well as a compromised brake system."
The owner who filed the complaint had driven the vehicle for two months and had 4,300 miles on it.
Kia officials did not immediately comment on the investigation.
The South Korean automaker launched the Soul in early 2009 and has posted strong sales for the funky compact wagon, helped by a memorable advertising campaign featuring rapping hamsters dressed in baggy clothes and hoodies.
The Soul was among 27 vehicles from the 2010 model year that received the "top safety pick" award from the Virginia-based Insurance Institute for Highway Safety. Vehicles are selected for providing the best protection in front, side and rear crash tests based on Institute evaluations during the year.