According to one entry of the chronology in the memo, officials of Delphi, which supplied the ignition switches to the recalled GM cars, told committee investigators that GM had approved the part, even though sample testing of the ignition switch torque was below the original specifications set by the automaker.
GM knew as early as 2001 that it was facing problems with its ignition switch, but no auto recalls were ordered until earlier this year.
A February 2005 entry in the congressional committee's chronology illustrates that engineers were grappling with what to do about the defective ignition switches.
"Engineers considered increasing or changing the ignition switch 'torque effort,' but were advised by the ignition switch engineer that it is 'close to impossible to modify the present ignition switch' as the switch is 'very fragile and doing any further changes will lead to mechanical and/or electrical problems.'"
The committee's memo concludes with a series of questions, which likely will dominate Tuesday's hearing with Barra. Those questions ask why it took GM so long to identify its ignition switch problem.
"Why did GM approve ignition switches that did not meet its specifications for torque performance? What was GM's assessment of the implications for performance and safety," the memo also asked.
It is also not clear yet who approved a revision to the ignition switch in 2006, and why the change did not lead to an earlier recall of older model cars to fix the problem.
- By Reuters