Good result back about this issue ryden, not read a resultant return on this fault at all as yet. I did notice on replacement Turbo's for sale that the waste gate was closed so actuator actually opens it and not other way round. Think I may need an actuator now. Or EGR blanking. Do both ok.

 

To be honest goggs, i had changed the boot pressure sensor and done various electrical fault finding before checking the turbo side of things. Then it all became clear in the end.

But as you say when the boost reaches a certain pressure it causes the actuator to open the waste gate, so it can relieve the extra pressure ( i believe that's how it works) if your interested i've posted what the workshop manual says.

If im honest i haven't had any dealings with the EGR side of things so i cant comment on it.

 

Yes that's it. Pressure to operate the actuator comes from a tapping into the turbo output boost manifold simple as that. Short hose as seen on turbo pictures.
Or think again, could this hose be blocked with carbon. Could the tapping hole into boost manifold be blocked. Answer relates to, does the EGR get blocked with same carbon. Could be worth checking first.

 

Its a possibility. My issue was to a degree blockage related, but it also compounded in my actuator failing. Or it was the other way round - actuator failed and then caused a build up due to not relieving.

I suggest like you say goggs, check all hoses/pipes are clear and at the same time no leaking.