NHTSA Complaint #11507538 — 2015 CHEVROLET IMPALA

In September 2021, my vehicle had approximately 130,000 miles and began to experience intermittent power steering failures. During these times, which were always unexpected, the Stabilitrak light would illuminate on the dashboard, and a "Power Steering" advisory would appear on the dashboard display screen. Power steering would then be unavailable until the vehicle was restarted. I am experienced in vehicle repair, and I isolated the left rear wheel speed sensor as the cause of this fault. I changed the left rear wheel bearing with an OEM replacement, and the problem went away. In January 2023, at approximately 160,000 miles I began noticing that my right rear wheel bearing was worn, and I changed it with an OEM replacement. Roughly 2 weeks later, my power steering has randomly begun to disengage while driving. The only message I receive is a "Power Steering" advisory, but this time, Stabilitrak remains operational. I am very concerned about this vehicle's design, which apparently kicks power steering offline as a result of anomalies with the wheel bearing speed sensors. The speed sensors consist of a circular magnet attached to the back of the bearing, and a device mounted within the bearing bracket which tracks the frequency of that magnet's rotation. The circular magnet is subject to corrosion and fracturing, as I discovered in September 2021, and again in January 2023, while replacing each bearing. This vehicle is quite heavy. A significant amount of damage, injury, and death is likely to occur if a driver with less capabilities than me is met with this awful fault while driving. Steering the vehicle in this condition, while below 50 MPH, is nearly impossible without enormous effort, especially around common 4-way intersections and at slow speeds. I believe speed sensor anomalies should not trigger a complete loss of power steering.