2011 Volvo 780 D13 Stalling randomly

I have a real problem with my Volvo Vnl 780 D13 2011 truck that has mysterious problems that nobody can resolve.
Truck simply stalls and loses the boost periodically and to a point that is impossible to drive. After many fuel filter changes and many trips to dealer and various repair shops nobody knows what it is. Not to mention truck has no codes on the dashboard. However with the Techtool I was able to detect some codes for J communication line that truck had. Dealer did all the diagnostic and claims it needs a new engine harness. It's extremely strange because harness is from decemer 2013. Not to be lazy I've checked everything for continuance and damage everywhere and all good. The first issue was a boost manifold sensor that was replaced immediately with no success. However there's a lot black residue in in filters witch is wary confusing. Some claim that this is coming from returned compression to the fuel trough injector cups witch is even stranger.

 

After some 300 ish $ in Volvo dealer this is what they concluded;
We run diagnostics and found using PTT that there was a folt J1939 where ECM was receiving sporadic information from boost pressure sensor and found that engine harness was faulty,exact words from Volvo tech.
This is somewhat hard to believe given that I inspect the harness completely.
Letting them to replace the harrnes would lead to one off thoes insane rep10000$ bills. The harrnes looks brand new and not original given that it has December 2013 date printed on it.

 

M $K north Indianapolis, quite large dealer but from past experience one learns that this is the way they operate and this is a fact.
Price for replacing a harness is shocking too around 2700$. And a brand new one appears dated December 2013.
I quoted exactly what they diagnosed.

 

Truck operates under zero stress hauling plastic parts and does virtually no idle.
508 thousand miles.

 

No because as soon as they plug in the tuck at dealer it automatically updates the software for the latest issue. The Tech Tool that I have access wasn't able to run any test other than basic diagnostics.

 

Yes 5V,and brand new sensor installed. Signal vise I'm not sure but Volvo claims it has funny signal riding trough PTT and want to replace the harrnes just like that.
Not sure what PTT is though.

 

Is there any other sensors and wiring around turbo that can be inspected. This cutt in the boost seams unorthodox so I suspect some electrical problem or fueling issue obviously.
What brings a lot of confusion is the J communication link code,is it possible that this just shuts down everything for split second and doesn't leave any codes dunno.