NHTSA Engineering Analysis EA11014

On March 31, 2014, General Motors Company (GM) submitted a Defect Information Report (DIR) to NHTSA describing a safety defect that may result in a sudden loss of power steering assist in approximately 1,340,447 model year (MY) 2004 through 2010 vehicles equipped with electric power steering (EPS), including 334,728 MY 2004 through 2007 Saturn ION vehicles that are the subject of EA11-014.GM has assigned the recall number N140115.The NHTSA recall number is 14V-153.According to the DIR, if power steering assist is lost, a message is displayed on the Driver Information Center and a chime sounds to inform the driver.GM indicated that steering control can be maintained in manual (unassisted) steering mode, but would require greater driver effort at low vehicle speeds, which could increase the risk of a crash.Sudden loss of power steering assist can occur in the subject vehicles if the system loses electrical power or whenever the system detects a fault that requires it to enter fail-safe operation mode, removing power from the EPS motor.GM?s DIR identifies three basic conditions that may result in loss of power steering assist in the recalled vehicles:power steering motor faults, torque sensor assembly faults, and power steering motor controller unit faults.GM will issue four service bulletins providing different repair procedures for recalled vehicles.Bulletin 14115 will provide repair instructions for replacing the power steering motor in MY 2004-2007 Saturn ION, 2009-2010 Chevrolet HHR (non-turbo), 2010 Chevrolet Cobalt and vehicles repaired in recall 10V-073 that received repairs prior to May 31, 2010.Bulletin 14116 will provide repair instructions for replacing the torque sensor assembly in MY 2004-2006 Chevrolet Malibu and Malibu Maxx, 2005-2006 Pontiac G6 and 2008-2009 Malibu, Pontiac G6 and Saturn Aura vehicles built from March 1, 2008 through June 27, 2008.Bulletin 14117 will provide repair instructions for replacing the torque sensor assembly and power steerin