So is it possible for the anti shudder to fail on an ASZ and not throw up any lights, whilst the EGR keeps working fine?

How bad is said "shudder" and when would it occur.. Low and high revs perhaps?

Is the anti shudder and anti stall the same thing?

Anti shudder valve only closes when you switch off the engine. Diesels tend to run on unless the charge air is stopped when you switch off. The shudder can be severe depending on how well the injectors are sealing, and if the engine is using oil due to worn valve stem oil seals or worn rings and bores.

Without an anti shudder valve, diesels engines can 'run away' if you get a turbo oil leak. They simply use the engine oil as a fuel source and it kills the engine big time.

Thanks Moggy.

I've just read on another VW forum you can turn down the effect (not fully off, though) of the EGR through VAG COM?

Anyone know anymore on this?

Edited 7 July, 201015 yr by Rob.

Thanks Moggy.

I've just read on another VW forum you can turn down the effect (not fully off, though) of the EGR through VAG COM?

Anyone know anymore on this?

Yes, you can enter a minimum value for EGR flow using VAG COM. Minimises the soot build up and no CEL as the ECU is expecting to see the reduced flow rates.