Lago Blue

with the "shiney cylinder". This sounds like it might be the black plastic housing style with a glued-on cap on the bottom.

This style moves vertically, like a door-bell chime, it doesn't rotate.

There is a Bosch (aluminum housing) which I believe is the rotary style.

I am confused about the spring Hubturn mentions. The piston has a groove in it that is visible through the port in the cylinder wall.

See a brief explanation of the open, clean & close VDO ISV procedure here:

https://www.audiworld.com/forums/sho...&highlight=vdo

hubturn

It is the black plastic VDO model. If you look in the groove in the piston, and actuate the ICV via the vag-com output diagnosis test, you can see the spring repeatedly move inside the piston through the slot in the piston until you select the next function in the test. Without a known functioning ICV, I don't know postitively if this is all the test is suppossed to do or if the piston should move. My gut feel is that the piston should move per the attached Bentleys page. Hence the trip to the junkyard.

Lago Blue

The "powered" test in the manual (as you have attached) is definately shown for the Bosch rotary style, not the VDO reciprocating style.

I don't know if this test is valid for the VDO type. I have done the resistance sheck on the VDO's.

I have not ever power-tested mine such as you have, only removed it's lower cap with a heat gun and actuated it's piston while rinsing it in the part's cleaner, and then again with some light oil afterwards. I could feel the spring behind the piston, but don't recall seeing it as you have. It may be that the piston is stuck due to scum in the bore, the spring may be only captive, and the lifting of the piston only done by magnetic pull, not mechanical connection, and only possible once the piston is freed up.

I think yours can be cleaned to be made serviceable.

After cleaning the OEM sealant from the cap and body, I re-attched the base cap with aviation sealant being carefull to ensure no air could leak in at the cap-lip to body seam.

Lago Blue

Here:

http://forums.quattroworld.com/12vv6/msgs/414.phtml