I figured it would be a good idea to have some maintanence and iformative posts on here. I got these from the UK site. I hope no one there gets upset with me lol.
Switch ignition on but don't start the engine. In the grey plug under the fuse box, connect the two right pins (chk and ign) with a paper clip for example, for 3 seconds (the engine check light will turn off while you are shorting them out). The engine check light will flash a series which will indicate a code -
Long long long long long (pause) Short short short short short - indicates 55 which is no fault.
If it flashes 3 long and 4 short for example it's the Det sensor.
To clear the ECU codes, short the wires out again while it is flashing the code.