I've had my 2013 S4 exactly 6 mos today, during which I have put on just over 12,500 miles. 80% highway driving - spirited but never pushed to the limit. No mods. Never taken to the track. I get just under 23 MPG overall so that should give an indication that I don't race stoplight to stoplight on a regular basis. I always use Shell or Chevron gas. Oil level is fine and engine temp was normal. Overall, I think I am easy on my S4 compared to a typical S4 owner.
The car ran fine this morning all the way to Miami (75 miles). When leaving Miami I got the message / light so I drove @ about 2,000 RPM all the way back to PB County and dropped the car off at the dealer. No other signs of a problem - the car ran and sounded fine. Surely it will be covered by warranty but I was wondering if anyone else has seen a similar issue on a 2013 yet. I should get diagnosis tomorrow.