2009 D13 Hot EGR

My D13 gives me codes of The egr is to hot, the exhaust gas to to hot, Nox level downstream which might be the nox sensor. Will low boost pressure give these hot problems. I don't have a boost gauge but thought of putting an aftermarket one on. My after cooler does have a small leak in it. Also how do you know when your truck derates. Lately its been running sluggish and I replace the fuel filters and I am getting a new air filter tomorrow. I cant keep letting Volvo guess and check and not put my truck back together properly. Thanks for the help if you can get through my unorganized mess.

 

That's what I am thinking now. I thing I am losing boost so I need to find the leak