The National Highway Traffic Safety Administration has closed its investigation into faulty electric power steering motors affecting 334,728 Saturn Ions from 2004-2007, because General Motors has issued a recall for them. The group’s research found that the part failed at a high rate in the vehicles.

GM recalled over 1.3 million vehicles a few weeks ago, including the Ion, because the power steering could suddenly fail. If broken, the cars could still turn, but it took greater effort. The automaker is also covering 96,324 2003 Ions with a lifetime warranty for their motors, but it’s not immediately replacing them.

NHTSA opened its investigation into the motors in September 2011, and it found 4,787 complaints and 30,560 warranty claims that showed failure for the Ion alone. It estimated a complaint rate of 14.3 incidents per 1,000 vehicles and warranty claim rate of 9.1 percent. The investigation also found evidence of 12 crashes caused by loss of steering, two of which resulted in injuries.

According to The Detroit News, the Ion wasn’t initially going to be included in the recall. During the House’s hearing into GM’s ignition switch recall, it presented an email from October 2011 to Mary Barra that notified her of the bad steering motors and said the “Ion data did not justify being included” in the recall. At some point, the automaker apparently changed its decision. NHTSA’s investigation report can be downloaded as a PDF.