Controller nut. PARK & REVERSE ASSIST. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Backup Sensing System Module. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Tire Pressure Monitor Control Module. Back Up Light Assembly Nut. Spoiler Nut. Tail Light Nut. Flange. Backup Assembly. C, Cooler, NO.1. Controller. Parking Aid Control. Spoiler. Tail Light. Tire Pressure Monitoring System (TPMS) Control.