Combine first 4 ingredients in a medium bowl. Combine yogurt, egg substitute, and margarine; add to dry ingredients, beating well at medium speed of an electric mixer. Stir in pecans.
Coat an 8-inch waffle iron with cooking spray; allow waffle iron to preheat. For each waffle, pour 1 cup batter onto hot waffle iron, spreading batter to edges. Bake 4 to 5 minutes or until steaming stops. Cut each waffle into 4 squares.