Engine dies while driving on fwy

I have a 2006 CC 4x4 with 140,000 miles, recently I was driving on the fwy and all of a sudden the engine dies. Luck that it was not busy and I was able to coast to the side. It has also died on me while i was just parked and idling and coming off a complete stop. The weird thing is that there was no error code or engine light on. I have Been searching and found the ECM replay problem and the IPDM problem. I have a appointment tomorrow to have the replay replaced, but should I also expect to have to replace the IPDM? Could there be another thing causing this the problem? I have just replace the crack shaft sensor, but could a bad camshaft sensor also cause this problem without having the engine turn on.