The kick-down feature is designed to give maximum acceleration.
If you press the accelerator right down past the point of resistance at full throttle when the drive select function is set to efficiency mode Link, the engine power is automatically controlled to give your Audi A4 maximum acceleration.
WARNING!
Please note that if the road surface is slippery or wet, the kick-down feature could cause the driving wheels to spin, which could result in skidding.