NHTSA Investigation PE10005

Electric Power Steering Failure

In a March 1, 2010 letter, General Motors Corporation (GM) provided a defect information report to NHTSA regarding a problem that could result in sudden loss of power steering assist in certain model year (MY) 2005 through 2010 Chevrolet Cobalt and MY 2007 through 2010 Pontiac G5 vehicles equipped with electric power steering (EPS).The letter indicates that the loss of steering assist could occur at any time while driving and that, once assist is lost, a message is displayed on the Driver Information Center (DIC) and a chime sounds to inform the driver.The letter further states that steering control is maintained in manual mode, but would require greater driver effort at low vehicle speeds.In the next ignition cycle, power assist is typically regained and the DIC message is no longer displayed.GM's letter identifies the root cause of the EPS failure as the EPS motor and indicates that production of a new motor started in December 2009.GM's recall repair procedure instructs dealers to replace the EPS motor in all recalled vehicles. ODI's analysis of all information available related to sudden loss of EPS assist while driving in the MY 2005 through 2009 Chevrolet Cobalt vehicles shows current complaint and warranty rates of 323/100,000 vehicles and 0.4% respectively.In response to ODI's request for information, GM identified 81 complaints where a crash was claimed that may be related to loss of EPS assist.ODI's analysis of all crash claims was based on verifiable factors such as; whether a loss of EPS was indicated at the time of the crash by a chime or malfunction indicator lamp or if a EPS related component malfunction was identified after the crash occurred.With this method ODI identified 36 possible crashes related to EPS failure.GM assessed crash claims based on the available facts and excluded crash claims that indicated that the vehicle was travelling at speeds in the range of 30 mph or greater.GM said that it believes if power assist is lost while a vehicle is moving at speeds in the range of 30 mph or greater there is a small difference in steering efforts perceived in subjective evaluations at those speeds and it is unlikely to lead to loss of vehicle control. Based on GM's safety recall, this investigation is closed.

An investigation is a separate record from a recall and from a manufacturer communication. A manufacturer campaign to repair a safety defect or a failure to meet a federal safety standard.