WASHINGTON, D.C. -

The Office of Defects Investigation within the National Highway Traffic Safety Administration is ramping up its efforts to examine the Saturn Ion after complaints continue to pour in about the discontinued model.

Federal officials explained the complaints are connected with faults in the electric power steering system. These faults may cause the system to suddenly shut down, resulting in an unexpected increase in steering effort and an EPS warning light.

A recent NHTSA notice covers a total of 382,474 Saturn units — the Ion from the 2004 to 2007 model years.

ODI said it has received 846 complaints and General Motors identified 3,489 reports alleging sudden loss of power steering assist. Officials indicated 16 of these complaints alleged that the EPS warning lamp had illuminated before or during the loss of steering assist, and the increased steering effort contributed to a crash.

Two of the GM crash claims indicated that the driver was injured in the incident, according to NHTSA.

In a previous preliminary evaluation, ODI investigated the sudden loss of power steering assist in 2005 through 2010 Chevrolet Cobalt vehicles. This past May in response to an ODI information request letter, GM provided federal officials with complaint, warranty and EPS system information related to EPS loss of assist for the Saturn Ion and peer vehicles Pontiac G6 and Chevrolet Malibu.

In that response, GM indicated that the EPS system used in the subject vehicles was the same as that used in the 2005 to 2010 Chevrolet Cobalt and Pontiac G5.

In March of last year, GM recalled approximately 1.05 million Chevrolet Cobalt and Pontiac G5 vehicles to correct a defect with the EPS assist motor. NHTSA recapped that the defect identified was described as a buildup of brush debris mixed with oily material on the EPS electric motor armature that causes the motor to stop functioning — the same problem identified in the Saturn Ion from the 2004 through 2007 model years.

ODI said it duplicated this failure in both a Chevrolet Cobalt and Saturn Ion previously tested at the Vehicle Research and Test Center (VRTC).

In the defect notification letter for the previously recalled Cobalt and G5 vehicles, GM stated that the vehicles may experience a sudden loss of assist that could occur at any time while driving and that if power steering was lost the vehicle would revert to manual steering mode and would require increased steering effort from the driver.

“ODI believes that, depending on driving circumstances this increase in steering effort could result in some loss of control and a crash,” federal officials surmised.

“An engineering analysis has been opened to further assess the frequency, scope and safety consequences of a sudden loss of steering assist in the subject vehicles,” they concluded.