Santa Fe Dirt Road Warranty restriction - Hyundai Motor America

2004 Santa Fe check engine light came on at 37,000 miles. Diagnosed as faulty evap close valve. Replaced at no charge. 2 days later light came back on. Diagnosed as "excessive dirt in cannister filter & close valve" Replaced at cost of $155.46. Dealer would not cover under warranty because "you live on a dirt road." There is no mention in manual as to any warranty restrictions if you live on a dirt road. Part is bolted to underside of car, why do they expect it to not get dirty? Complained to Hyundai America, got no response, complained through Better Business Bureau, got no response from Hyundai. What is their definition of SUV? Do you really want to work for a company that doesn't honor its warranty?