What does this mean, apart from the engine not achieving the requested boost pressure.

I have eliminated / about to eliminate all of the other fault code symptoms, this one I cannot find much about...

Have a look here page 14 (N75). If you look down to the turbo from the MAF you will see a small pipe going into the top of it.

I had to get a new one as the top lug had snapped off and was over boosting, Its a ball ache to change on your back on the drive.

That is really appreciated.

I've got a new pressure relief valve (page 11) as they are I'm told prone to fail after a remap. Looks like it could be a broken N75, although mine is not over-boosting, I'm having te opposite problem where it seems the turbo impeller speed is being reduced.

How much is one of those? I've almost spent as much on new valves and diagnostic as I have on the remap!

And this bit:

"The maximum

charge pressure is thereby restricted to

a basic operating charge pressure"

suggests limp home mode. It's certainly not limping, and I would imagine that the boost pressure in this mode would be the same even if remapped.

I think it was around £30. I got a new pcv too you will know if that goes as your idle will be up and down.

Idle is fine, so its probably not the PCV valve, nor is there oil leaking around the filler cap. Fuel economy is really pants though, around 5mpg down on what I have been getting all year.

n75 solenoid. Mines been defective for 18months (yep, I'm slack). Bought a new one just last week AUD49. Looked at it on Saturday & decided i'd rather go for a bike ride & leave the heartache to the mechanic i use.

Symptoms are that it boosts, then goes flat-ish at about 3000rpm, then boosts again at about 4000rpm. Fuel economy around town has blown out about 15%. Also gobbles fuel on the motorway if rpm is above 2200.

Well, changing ythe PCV hasn't solved my lack of power, so it's either a new N75 or perhaps better still a trip to the dyno all wired up to see what's going inside. That first week of tyre shredding bliss is fast becoming a distant dream like memory...

have you had a proper VCDS scan done mate, if not PM me and we'll get you one sorted

have you had a proper VCDS scan done mate, if not PM me and we'll get you one sorted

I had the first scan done by Barry VW specialists (who I assume are capable of doing this), and the garage in cwmbran that I have used before apparently has one. Both came up with P0299 - mechanical fault with the turbo, although today analysis after a full week suggests it's an intermittent fault, and didn't re-appear during the the test drive this afternoon after the PCV was fitted. There is no variation or hesitancy in output, it's still smooth, pulls to the redline ok; no flatspots or misfires. Engine is perfect, just now somewhere between stock and full remap.