NHTSA is looking at possible corrosion problems involving the last-generation Hyundai Sonata.

Federal safety regulators have launched an investigation into reports that rear suspension frames on older Hyundai Sonata sedans can rust and fail.

The investigation targets about 393,000 prior-generation Sonatas build between the 2006 and 2008 model-years and sold in the American market.

According to the National Highway Traffic Safety Administration, excess corrosion could lead to failure of the vehicles’ control arms – which, in turn, are attached to the wheel hubs.

Such an incident could lead to a loss of vehicle control and possibly a crash. In fact, NHTSA has so far received reports of six suspension failures including three occurring at highway speeds. No crashes or injuries were reported, however.

The reports cited on the NHTSA website include one from Pennsylvania where the car began to swerve while being driven. A mechanice later found the rear frame was cracked and corroded, with the tires showing premature ware.

Preliminary investigations such as this one have become more common in recent years as the federal agency responds to a series of high-profile safety issues. It is not clear that it will lead to a recall.

Rust and corrosion have been historic problems for the auto industry, particularly concerning body panels. But modern steels and the use of updated coating systems have helped minimize the issue, in general.

Nonetheless, there have been a series of corrosion-related recalls involving a number of major manufacturers over the last several years, including one at Ford in mid-2011 that forced the repair of 1.2 million pickups, several involving Toyota products such as the Sienna minivan and, most recently, the March recall of 76,000 Acura TSX sedans.