Can anyone tell me if you should see the anti shudder valve mechanism move on the side of the EGR body when the engine is switched off? If you don't know, then would appreciate if some kind soul could oblige and take a look at what happens with theirs for me?

Mine just sits there, works if you move it manually but other wise nothing.

Is the ECU supposed to tell the solenoid valve block to make it work by creating a vaccuum in the rubber hose when the ignition key is turned off?

yeah, basically what you said , the ECU tells the vacuum unit on the O/S inner wing to close the valve

get the fault codes read with Vagcom

What engine code is your car?

If it's ASZ it's vacuum, if it's BLT it's a motorised valve.

It's an ASZ so vaccuum operated, any idea what the vaccuum 'pressure' should be to that and the EGR diaphragm?

check the pipe going to the valve for splits

supply vacuum should be around -0.7 bar...

Kev

Mine had a problem and wasnt working, I traced the fault to a hole in a pipe which routes close to the exhaust (see pic)

Check all pipe carefully

Vacuum test gauge confirmed the supply was working exactly as it should, so I think the diaphragm had gone (slight whistle) as the valve wasn't doing its stuff.

With EGR throwing up a CEL code I put new EGR on last weekend and so far so good, just have to watch that space and hope it's sorted. Tested the new valve before fitting by plugging into the ASV vacuum line before taking the old valve off and the flap on the new one actuated perfectly, so vacuum feed lines were all good.

Edited 3 November, 200916 yr by Greybeard

its always nice when someone reports back after the fault has been fixed with what was replaced, so thanks for that