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NHTSA Preliminary Evaluation PE20009

Preliminary Evaluation · Momentary Increased Steering Effort · Opened 2020-06-01 · Closed 2022-06-03

Investigation

Action number
PE20009
Type
Preliminary Evaluation
Open date
2020-06-01
Close date
2022-06-03
Manufacturer
General Motors, LLC
Affected makes
CHEVROLET; GMC
Affected components
STEERING; STEERING:ELECTRIC POWER ASSIST SYSTEM
Affected model years
2010, 2011, 2012
Affected (make, year) variants
12

Summary

On June 1, 2020, the Office of Defects Investigations (ODI) opened PE20-009 to investigate instances of a momentary increase in steering effort after the vehicle is driven in a straight line for a period of time due to an issue with the steering gear in model year (MY) 2010 through 2012 Chevrolet Equinox and GMC Terrain SUVs.If the electric power steering system fails to operate as intended, the driver will experience momentary increased effort when attempting to turn the steering wheel from the straight-ahead position. For this condition to occur, the driver would need to have traveled in a straight line at a sustained high speed, without turning the steering wheel, for approximately 30 minutes or longer. The steering gear contains a servo unit that includes a worm gear with a worm and a worm wheel. General Motors (GM) stated that the primary root cause of the increased steering effort is the supplier's inconsistent application of grease in the interface between the worm and the worm wheel. The grease may have been applied in a location on the worm wheel that didn't interface with the worm, depriving the worm gear of proper lubrication.On November 1, 2014, GM issued Special Coverage 14232 to address the power steering stick-slip issue in MY 2010-2014 Chevrolet Equinox and GMC Terrain; MY 2011-2014 Chevrolet Cruze and Volt; MY 2012-2014 Buick Verano; and MY 2013-2014 Chevrolet Malibu vehicles. GM notified consumers via mail.The Special Coverage repair includes the replacement of the steering gear with an improved internal worm gear greasing process for MY 2010-2012 vehicles. For the MY 2013-2014 vehicles, the Special Coverage repair includes a reprogramming of the steering gear control module. The new software has an anti-stick feature which senses and reduces the friction between the worm and worm wheel by oscillating the worm gear. GM stated that the difference in remedy is due to the inability of the MY 2010-2012 steering gear control module to accept the new sof

Source

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NHTSA ODI investigation page
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