In some areas, a vehicleâs underbody may exhibit corrosion due to road salt usage. As a preventative measure, cavity wax coating is applied to the internal surfaces of underbody components, and an undercoating spray is applied to the bottom exterior surfaces of specified underbody components. This bulletin describes the procedure to perform this preventative service on certain Genesis Sedan (BH), Equus (VI), and Genesis Coupe (BK) vehicles.
