406 Engine Electrics

[splitpin]

Hi,
I have plugged my wifes 406 Exec Estate 2.0HDi 110 upto PP2000.
I can't seem to read the Engine ECU properly. It does not produce any P???? Fault codes, though the Fault Light is on.
What it says is "Circuit TL4226 Fault. Faulty Circuit". Can anyone shed any light on what this circuit is?
The Engine Fault Light goes out as quick as it comes on.
It usually comes on not long after start up from cold after descending a hill. Doesn't do it when warm, or when cold if driven on flat roads.
Any Ideas?
Also I can't find where to enable the Cruise Control on the Engine ECU and does anyone know what fonction super verrouillage is?
Many Thanks,
Graham.