Did you try a new battery? It wont fire the coils if the voltage is too low. Most dealers cannot diag a controller. Usually, it is a..."we tried everything else, so it has to be that controller." It could be, but it may not be. I would also check your fuse box and look for blown starter relays or fuse. Ask the dealer if they reviewed all the circuits. Also, look over all the ground wires on your sled. It wont fire if there is a corroded ground wire. If you own a turbo, I suggest getting use to working on a few items. They are mechanically very reliable, but every once and a while you may have a weird wiring issue. I have personally had wires become brittle because of engine bay heat and break internally, causing a no start issue. The dealer found the wire and fixed it for me. The rest I do myself.