PREHEAT oven to 350°F. Grease and flour two 9-inch round cake pans. Beat cake mix, 1 cup of the pumpkin, the milk, oil, eggs and 1 tsp. of the pumpkin pie spice in large bowl with electric mixer on medium speed until well blended. Pour evenly into prepared pans.
BAKE 28 to 30 min. or until wooden toothpick inserted in centers comes out clean. Cool in pans 10 min. Remove from pans to wire racks; cool completely. Beat cream cheese in small bowl with electric mixer on medium speed until creamy. Add sugar, remaining pumpkin and remaining 1/2 tsp. pumpkin pie spice; mix well. Stir in the whipped topping.
CUT each cake layer horizontally in half with serrated knife. Stack layers on serving plate, spreading the cream cheese filling between layers. (Do not frost top of cake.) Drizzle cake with caramel topping just before serving; sprinkle with the pecans. Store leftover cake in refrigerator.