excessive moisture in egr valve

[williamsbuilding]

I did have a new engine wire harness installed during inflame, but seems as though it must be electrical or an ecm failure of sorts. Ecm is 5 yrs old. My mechanic is a Volvo mac dealer, known him for 6yrs, lives in my town and I feel he shoots me as straight as possible. That being said, I'm sure he and or his mechanics don't know everything. Thanks for info to purchase hardware for computer, where do you suggest I get software? I am ready to get it to at least know whats going on when I hire a wrench.
Thanks again for your time.