This may well be a stupid comments but when your engine is running does this:

make a fairly loud buzzing noise? Just wonder as I've never heard/noticed it before.

i`ve taken that thing off/unplugged it loads of times and even lost a screw from it but no buzzing noises whilst engines idling or otherwise.

hmmm maybe that's the cause of my fabia current issues? :confused:

What does the component actually do?

Thats the vacuum box - pipes go off it to the airbox/turbo/inlet, etc.

Would have thought if it was faulty, it would bring up an error on the ECU - as an aside, if a pipe had popped off somewhere (assume you've checked all 6 terminations off it? ) it could cause the limp mode you're suffering with.

Trace and verify where all those pipes go to, especially the one going to the turbo.

Jay I'm thinking you could be right Mr roo has kindly offered to check the fault codes for me tomorrow.

One of the pipes is loose but I dont know if it was before :confused: shame the master techie isn't about anymore :(

The pipes themselves are loose - they're just bits of rubber and flap about a bit - It if you pull one and find its not attached at the other end , that you'd better worry. If you find one not attached, tell us which number pipe it is (numbered 1 to 6 right?) and we should be able to tell you where it should connect to.

PS: If you search for "vacuum" I expect you'll find a thread from me asking where the pipes all terminate to, and I'm sure there was a concise answer in that thread.

I had a fiddle with them last night, they were loose but seem to be attached, though I didn't want to pull it too hard, in fear it may break!

Those vacuum pipes operate various functions on the engine Mike.

Wastegate Bypass Regulator Valve N75

The engine has a variable turbine geometry for optimally adapting the charge pressure to the actual driving conditions. To regulate the charge pressure, the

vacuum in the vacuum unit for turbocharger vane adjustment is set depending on the pulse duty factor. The Wastegate Bypass Regulator Valve N75 is activated by the Diesel Direct Fuel Injection Engine Control Module J248.

Effects of failure

If the Wastegate Bypass Regulator Valve N75 fails, the vacuum unit reverts to

atmospheric pressure. As a result, charge pressure is lower and engine performance is impaired.