Had a 2014 tdi in last week going into limp mode under load, glow light flashes on dash. Fault resets every time ignition is cycled.

p2279 intake air leak stored in ECU.

carried out air leak test with smoker, no leaks present .

Fault turned out to be faulty MAP sensor giving incorrect readings, only available from the dealer at present time .. retails at 52.28 + vat

Nice little DIY fix that will hopefully help some of you

Audi A4 P2279 Intake Air Leak Fault *FIXED* - YouTube