P0401 ERG Low Flow on Octavia '05 1.9TDI

I'm having a problem finding the fault that is putting the yellow engine light on. The code reader I have say's it is P0401.

I have cleaned the valve as recommended by several DIY car maintainers (followed the youtube clips that are offered when you search the fault code)... anyway, all seems fine for a day or so but the light keeps coming up.

not sure what the freezeframe data is (I can guess a few though) but thought I would put them on here  in case they mean anything to anyone with suggestions..

PCT(%) - 22.0

ECT (^oC) - 45

MAP (kPa) - 119.0

RPM - 1762

USS (Km/H) - 44

IAT (^oC) - 17

MAF (g/s) - 32.36

TP (%) - 94.9

Any ideas?????