Congress is investigating why GM didn't recall the cars sooner, because it first found problems with the ignition switches in 2001. It's also questioning federal regulators from the National Highway Traffic Safety Administration, who didn't investigate the cars despite evidence of a problem.
GM CEO Mary Barra and NHTSA Administrator David Friedman are scheduled to appear Tuesday before a House Energy and Commerce subcommittee. A separate Senate hearing is scheduled for Wednesday.
The House memo provides new details about GM's consideration — but ultimate rejection — of potential solutions.
According to the memo, GM engineers met in February 2005 to consider making changes to the ignition switch after reports it was moving out of position and causing cars to stall. But an engineer said the switch was "very fragile" and advised against changes. In March 2005, the engineering manager of the Cobalt closed the case, saying an ignition switch fix would take too long and cost too much, and that "none of the solutions represents an acceptable business case."
In May 2005, the company's brand quality division requested a new investigation into ignitions turning off while driving, and a new review suggests changing the design of the key so it wouldn't drag down the ignition. That proposal was initially approved but later cancelled.
In a statement released Sunday, GM said it deeply regrets the events that led to the recall.
"We are fully cooperating with NHTSA and the Congress and we welcome the opportunity to help both have a full understanding of the facts," the company said.