EPC Light on Dash 2.0 Tdi

Hi there, I have a 54plate Audi A3 Sport, 2.0 tdi.
A light has came on flashing EPC
Since its been on i have noticed the car being quite smokey
Can someone tell me what this is?
Thanks

The only way to tell what is wrong is to give it a fault code read, even the most experienced mechanic in the trade would not work on it without a fault code scan.

Yea true I understand, Are there any main causes for this to come on??

There are dozens of possible reasons, some common some not so. Brake light switch failure is a common one but I don’t remember that making them smoke which is puzzling.