2009 berlingo 1.6 hdi EGR issues?

[berlingo2468]

Hello, 
I was hoping some of you knowledgable people could give me some insight into what my van is doing.

I bought a van about 8 months ago. 2009 berlingo 1.6 hdi 220k miles. 
I love it, however its always been under powered (i just assumed thats what a van was like lol). Also, if i put my foot down, some black smoke comes out the exhaust.

The check engine light used to come on and off, and to be totally honest, i just ingored it  
Today ive scanned the check engine light with one of those cheap scanners, and the codes are:
P0406 - EGR flow sensor A circuit high imput
P0299 - Turbocharger underboost
P0401 - EGR flow insufficient
P0409 - EGR flow sensor A circuit 
P0490 - EGR control circuit high

Just wondering if anything springs to your minds when you see these codes?

My plan is to youtube 'how to clean an EGR' and crack on lol

[shtu]

My guess is that there's an air leak somewhere on the pressure side of the intake pipework.

[evdama]

The 75hp is an understressed engine so once fixed don't expect warp 7 from it.