The National Highway Traffic Safety Administration announced that it will be investigating about 500,000 Ford sedans over potential problems in the steering mechanism.
The NHTSA's investigation will involve Ford Crown Victoria, Mercury Marauder and Mercury Grand Marquis sedans with model years 2004 to 2007.
The examination will include "incidents of steering shaft obstruction caused by interference from a dislodged heat shield."
The agency's decision to initiate a preliminary evaluation on the involved vehicles was brought to action after the NHTSA received five complaints regarding the issue, including one case that led to an injury.
The injury was reported in April, when the driver of a 2004 Crown Victoria injured his neck and lower back when the vehicle rolled over after the steering locked up.
In the complaint of the driver, he said that he discovered the heat shield beneath the vehicle, looking like the part broke off after rusting.
Other complaints regarding a similar issue reported steering that became very tight or difficult, sometimes even getting to the point that "bodily force" was required to turn the driver's wheel.
In an official document that launches the investigation, the Office of Defects Investigation of the NHTSA describes the problem as the "separation of the lower steering column shaft from the upper steering column shaft resulting in a loss of steering control."
The NHTSA usually launches a preliminary evaluation when the agency believes in the presence of a harmful defect in a vehicle, after receiving complaints from consumers and information from manufacturer service bulletins.
After the evaluation and analysis, the NHTSA may require a recall for the affected vehicles.
Ford has already issued a recall in the past involving the Crown Victoria and Grand Marquis sedans. In August 2013, the two models, including the Lincoln Town vehicles that are usually used as police cars, were issued a recall that involved over 300,000 units. The recall was issued in states where salt was heavily used in roads, which could corrode the lower intermediate shaft and cause the collapse of the upper intermediate steering shaft.
Kelli Felker, Ford spokeswoman, told Reuters in an e-mail that the company will be fully cooperating with the NHTSA during the investigation.
Late last month, Ford increased the vehicle recall for 2014 F-150 pickups from an initial number of 372 to 5,675. The recall was launched after an improperly placed motor position sensor was discovered inside the vehicle's electronic power assist steering system, which could lead to a sudden loss of power steering while moving.
