The contact owns a 2009 Mercury Mariner. The contact stated that while driving at an undisclosed speed, the contact became aware that the electronic power steering was not functioning properly, requiring an increased effort to maneuver the vehicle. The vehicle returned to normal functionality, but the failure became a regular occurrence. No warning lights were illuminated. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 14V284000 (Steering); but the VIN was not included. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA Hotline for assistance. The failure mileage was unknown.