I have followed many other folks' questions in regards to TIUs not being able to find DCS locos. NO DCS ENGINE FOUND error. It was quirky getting My two PS2 engines to work on DCS. One would work, then the other, then both for a brief time, then neither, then one, then finally neither ever again. Both locos worked fine running from the transformer, and I tried every suggestion given by forum members and from Barry's book. I also followed suggestions from Steve Nelson aka Mr. Muffin, and others on FaceBook. The last it worked was early February when I was off work with my first hand sugary. I was pretty sure My TIU had quit working, but wasn't able to call in while at home during their service hours until today. I am off work with my second hand surgery. I have been fighting this since last summer, thinking it must be me. Fortunately it quit altogether since my warranty runs out at the end of March. After the MTH representative ran me through some of the same trouble shooting tests you folks have suggested, he said it will have to go into the factory for warranty repair.
And so the moral to the story is: Get Barry's book, and follow the advice of Barry, Gunnrunner John, Pine Creek RR Dave, Marty, Steve, and the other DCS experts on this forum. The factory rep had nothing else to suggest than what the folks on this forum had.
The only downside is, they project 4 to 5 weeks for repair. Oh well. I can still run conventional. Then I can start my DCS experience from scratch again. Ha, ha!!