So good to hear that you got it all figured out.
For interest, check out
this post - similar issue. Interesting that your code numbers were quite different, but both yours and in the link I just referenced deal with "charge pressure." Also, in both cases the problems were solved with replacement or cleaning of the MAP (Manifold Absolute Pressure) sensor.
So obviously my thoughts about the EGR/throttle valve being the source of the problem were wrong - sorry! Not sure whether the MAP failure was due to CBU, or failure due to another mechanism. If you were really a Curious George, you could clean the old MAP sensor and see if it still worked! Nah - too much work, and things are all good now!
Thanks for posting the resolution of this problem - very helpful.