Table 1 shows one common structure related problems of the 2018 Audi S4.
| Problem Category | Number of Problems |
|---|---|
| Body problems |
There are two large "underride guard" panels on the underside of the vehicle that are fastened by small, loose-fitting plastic clips. There is also felt sound-deadening material on the exterior side of this panel. When the vehicle is driven in rain or snow, the panel collects snow or water under normal driving conditions and breaks free unexpectedly, causing the panel to contact the road and drag on the ground. This dragging causes a "rudder effect," pulling the vehicle rapidly and unexpectedly in an unpredictable direction. The vehicle is in motion at varying speeds when this occurs; it has occurred at approximately 30 miles per hour, 40 miles per hour and 65 miles per hour.