Spritz the inside of a 6 quart oval slow cooker with cooking spray.
Using an electric mixer beat together cake mix, flour, butter, buttermilk, chocolate syrup, eggs and vanilla. Beat for 1-2 minutes until fully combined.
Fold 1/2 cup chocolate chips and pecan pieces into the cake batter by hand. Spread the batter evenly onto the bottom of the slow cooker.
Using a teaspoon dollop the caramel pecan icing over the top. Use a knife to swirl through batter leaving a 1 inch border along the edge.
Cover the opening of the slow cooker with doubled paper towels first, then place the lid on top. Cook covered for 2 hours on high. (The paper towels will prevent condensation that forms on the lid from dripping into the cake. Don't skip it.)
After 2 hours uncover remove paper towels and test the center with a toothpick. If you see moist crumbs, it's done. If not, continue to bake in 15 minute increments then retest. Leave uncovered while you prepare the ganache.
Ganache: Melt 1 cup chocolate chips and 1/3 cup of heavy cream on 50% power in the microwave, stopping every 20 seconds to stir. Repeat until smooth.
Drizzle the cake with the chocolate ganache and allow it to rest uncovered for about 20 minutes before serving. [If you prefer a more traditional icing...Leave off the glaze and top with an additional can of coconut pecan icing or homemade German Chocolate Cake icing. To cut the cake: Cut through the middle, from end to end, then into wedges. You may also scoop desired size portions into a bowl..
Serve warm drizzled with vanilla ice cream or fresh whipped cream.