Federal safety regulators have opened an investigation into steering problems with the Saturn Ion.
The National Highway Traffic Safety Administration said it has received 633 complaints alleging sudden loss of power assist to the steering in Saturn Ion vehicles from the 2004-2007 model years. About a third of the complaints to NHTSA were filed in the last six months.
The cars were manufactured and sold by General Motors Co. but the automaker scuttled the brand and closed its operations last year as part of its bankruptcy reorganization. GM has sold 384,000 Saturn Ions.
NHTSA said it had received four complaints alleging that the defect contributed to an accident. At least one person reported an injury.
After an inquiry from safety regulators this year, GM said it knew of 638 complaints and 1,444 warranty claims for loss of power steering in the vehicles. The automaker said the complaints included seven crash claims, with three injury allegations.
In March, GM recalled about 1 million Chevrolet Cobalt and Pontiac G5 vehicles to correct a similar problem. Those vehicles' power steering systems were substantially the same as the Saturn's, regulators said.