car doesn't start
 

I own an automatic a4 tdi s/line. Sometimes when I try to start it, it doesn't turn over and the dash flashes

Can you add a bit of granularity to your post, what exactly flashes and how exactly? Video if possible. Are you driving a manual, tip auto, cvt auto? Is the engine cranking? EPC light on? Etc. Hard because tdi isn't offered here in the states.

yeah, need a little more info. Kind of sounds like low battery symptoms, or maybe a starter is on its way out. give us a little more to chew on :)