MM, it seems that my position c4 can be drawn

edit: I'm blind :P

I think this works. The key move being 3.Kb5 as dracoms discovered first.

dracoms, Thanks for pointing that out. However, in response to your main line 3. Kb5!, 3... Kc3 is also a non drawing move as black should play 3... Kd4!! instead.

Now I'm confused. I need to go back to the drawing board.

P-to-D4, 3. Kxa4 is met by c5, which wins for black

...because after a7, Qc8 and the pawn can't promote.