P0401 ERG Low Flow on Octavia '05 1.9TDI

Sorry Guys and Gals, Posted this in the wrong Forum....

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

I have cleaned the valve as recommended by several members and 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 eml keeps coming back.

I'm 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 - Engine Coolant Temperature?

MAP (kPa) - 119.0

RPM - 1762 - rev's per min

USS (Km/H) - 44

IAT (^oC) - 17 - Intake Air Temperature?

MAF (g/s) - 32.36

TP (%) - 94.9 - Throttle Position??

can anyone confirm these readings and fill in the blanks??

Any ideas how I can check if the valve is working?????