17705 + car not making requested boost

[Effect]

17705 on cold mornings (pressure drop between turbo and throttle valve) cycle of the ignition resets it and take sit out of limp mode.


Taken to JBS today, they have checked for vac/boost leaks also tested N75 valve all ok.

the have advised it needs further investigation and they suspect the turbo wastegate or cat blockage.
the ECU is requesting 1.4bar and only making 1.2bar
MAF reading is ~180g/s

what do people here think ?

 

[Effect]

posted this in a rush earlier.
James' explanation was that he thinks the wastegate has cracked so it cant seal fully therefore leaking boost, and throwing up a 17705 error code and also not making requested boost.
He seems to think it will most likely be the Turbo.

I had a think about this and surely if that were the case then it wouldnt just do the limp mode thing on cold mornings ?


what else can cause the car not to make requested boost ?


regards
James