Government Deepens Investigation of Saturn Ion for Steering Problem

The National Highway Traffic Safety Administration is a step closer to concluding that General Motors should have recalled 384,000 Saturn Ions in 2010 as part of a larger recall that covered one million Chevrolets and Pontiacs for a steering problem.

The agency posted a document on its Web site over the weekend saying that it upgraded its investigation into Saturn Ions from the 2004-7 model years as a result of heightened concern that a sudden loss of electric power steering could cause crashes.

The document shows the agency has 846 complaints from Saturn owners and G.M. has almost 3,500. There were two reports of driver injuries from crashes.

The document also said that the agency tested an Ion and was able to duplicate the type of steering failure that caused the 2010 recall of one million 2005-10 Chevrolet Cobalts and 2007-10 Pontiac G5s.

General Motors had resisted the Cobalt and G5 recall, saying that even if the power assist suddenly failed, the driver would be able to control the car, although it would take more effort to turn the wheel. The safety agency did not agree, concluding that such failures would increase the risk of a crash.

Shortly after the recall, the agency received a letter from G.M. answering several questions posed earlier by the agency. One answer noted that the Saturn Ion was equipped with the same power steering system as the Cobalt and G5.

G.M. argued that the Saturns did not need to be recalled. Alan Adler, a spokesman for G.M., said that the Saturn failure rate was far lower and the automaker was providing those owners with a 10-year or 100,000-mile warranty. Eric Bolton, a spokesman for the agency, said that N.H.T.S.A. did not insist on a Saturn recall because it did not have enough proof of a defect.

Even so, the agency began collecting information, including complaints, and last December it opened a recall query, an investigation into whether a recall was adequate.

The recall query has now been upgraded to an engineering analysis, a step closer to a recall.

Mr. Adler said that the automaker was cooperating with the agency. Mr. Adler did not respond to a question about the company’s earlier assertion that the vehicles did not need to be recalled.