Just come on - not flashing. Book says 'emission performance of engine management system impaired'. What's it likely to be please?

Try turning off and back on........may just be a software glitch. If not resolved do that a few times and then I'm afraid you may need a dealer. TDV6 - gone
TDV8 - gone
Audi Q5 3.0 Tdi Sline wef 6/11/10

Mine did this in the recent very cold weather (not necessarily any direct connection but it went off again when it warmed up) LR specialists computer showed fault as the EGR valves (apparently quite common). No other real symptoms except the performance seemed a bit "flat". Light went off when it warmed up but it had been booked into main dealer by then and they changed the valves yesterday (at least they say they did how would I know? All dealt with under warranty). Can't say as changing the valves has made any obvious difference and had it not been under warranty the LR specialists preference would have been to blank them off completely. Waiting for the light to come back on now  Gordon Kerr
Bedford, UK
2007 Java Black RR Sport TDv6
1980 Brooklands Green Triumph TR7

Thanks both - turned off and on quite a few times - no joy. Stealers it is then!