A congressional committee investigating General Motors has released a report by a supplier which assessed an “anomaly” in a crash test on a pre-production Chevrolet Cobalt. The report said that the supplier -- Siemens VDO Automotive -- has urged GM in 2004 to look closer at the relationship between the ignition system and airbag deployment.
A July 1, 2004, report by the supplier assessed the reasons why frontal and side-impact airbag sensors simultaneously shut down less than two-tenths of a second following the moment of impact. The report was written around a month before the carmaker starting producing the first Cobalts.
The report assessed both the results of the crash test and a series of laboratory simulations conducted by Siemens VDO to see how the airbag sensors would respond to a loss of power.
Siemens engineer Douglas McConnell wrote in the report that the cutoff of the sensors “appeared to be indicative of an ignition cycle.” He recommended that future severe crashes have ignition voltage and [in-vehicle network] messages monitored to find out the root cause of the Power Off issue.
While the report doesn’t tag the faulty ignition switch as responsible for the power loss, it was consider as significant since it shows that a GM-commissioned analysis had flagged a possible relationship between a loss of power and airbags not deploying and recommended that the carmaker determine the root cause – all done even before GM built and rolled out its first production Cobalt.
According to an investigation conducted by former federal prosecutor Anton Valukas, GM’s inability to recognize the connection was the primary reason for its failure to identify the defective ignition switch as a fatal safety flaw.
His report remarked that the connection to airbag non-deployment was not widely understood by GM employees until almost five years after the 2004 crash test. He wrote in his report that GM engineers inexplicably failed to recognize that the loss of power from a key moving into accessory caused the airbag system to shut off. [source: automotive news - sub. required]