I suppose that one of the lessons that all of us need to learn is to completely describe the problem when asking for help. This includes basic informations such as the type of engine (HO, O 3-rail, O 2-rail, PS-1, 2, or 3, battery, BCR, engine model number, etc.) This would go a long way to getting a the right answer as quickly as possible. For example, you won't get any advice about checking the battery on a PS-3 engine because those engines don't have batteries.
I am surprised that you are running a HO PS-3 engine using DCS. Everyone that I know who runs MTH engines with command control uses DCC. (I am a member of a large HO club and many of the guys have MTH engines.)
I have two scale wheel MTH O gauge PS-3 engines. I only run them in the 2-rail mode using DCC.
NH Joe
