Change the TDC sensor, worked for me, Apparently quite a common problem on the scenics, The new sensor comes with a new loom and connector which you have to connect to the existing wires from the old one. The kit comes with a couple of wire connectors that have to be soldered to the cables. I used slightly different connectors to make it easier.
Reletively easy job if your a little mechanically minded.
Paul
July 2007