My friend has an 2006 D12 670 he's getting this code in question, he has replace the Low Pressure Sensor on the manifold ( turbo boost sensor ) and still having the same code, plus he has no turbo boost, when this code is Active.
When this code is not Active truck runs find.
After replacing the turbo boost sensor the code is Active all the time!
One more thing when he bought this truck his differential sensors never worked properly sometimes they work or not. Mostly not.