The National Highway Traffic Safety Administration, the government's auto safety watchdog, also didn't seek a recall of the compact car from the 2004 through 2007 model years even though it opened an investigation more than two years ago and found 12 crashes and two injuries caused by the problem.
The documents, posted on the agency's website, show yet another delay by GM in recalling unsafe vehicles and point to another example of government safety regulators reacting slowly to a safety problem despite being alerted by consumers and through warranty data submitted by the company.
A recall can be initiated by an automaker or demanded by the government.
Both GM and NHTSA have been criticized by safety advocates and lawmakers for their slow responses to a deadly ignition switch problem in 2.6 million GM small cars. GM admitted knowing about the problem for more than a decade, yet didn't start recalling the cars until February. The company says it knows of 13 deaths in crashes linked to the ignition switches, but family members of crash victims say the number is much higher.
The Ion was one of a few GM cars included in a March 31 recall of 1.5 million vehicles worldwide to replace the power steering motors; the recall also covered some older Saturn Auras, Pontiac G6s and Chevrolet Malibus. If cars lose power steering, they can still be steered, but with much greater effort. Drivers can be surprised by the problem and lose control of the cars and crash.
In a statement issued Saturday, GM admitted that it didn't do enough to take care of the power steering problem.
NHTSA closed its investigation into the Ion because GM had decided to recall the cars, according to the documents released Saturday.