Exclamation Mark under hard acceleration?

[-ollie-]

Chaps,

If I put my 2001 S8 into Tiptronic mode, and pull away hard in first from a standstill, I get an exclamation mark come up on the centre of the binnacle, which stays for a few seconds accompanied by several beeps. It then goes out, and normal service is resumed.

My car's been into a VAG specialist today to have some minor things taken care of, and had the codes read whilst there - nothing came up, not on gearbox or engine.

The car was taken out for a lengthy road test (circa 40 mins) and the exclamation symbol came up again under the same circumstances. But even after that, no codes could be found.

What could be the cause of this guys? Car is driving perfect to me, and the garage have given it a clean bill of health.

TIA

Ollie