Emissions

My check engine light is on. Had it scanned at an auto store and had it fail emissions with code p0440. Had a friend smoke the system, the smoke only seemed to be coming from a vent connected to what I believe is the leak detection pump. He said it is probably the detection pump that needs replacing. Now he is not a car mechanic, and I cannot afford to be replacing random parts. I went and asked a mechanic and he told me to clear the code, drive for an hour an then try having it tested. My question I guess is should I trust my friend that it is the pump? The smoke comes from the cylinder shape, which I am sure is a filter, and is vented on the other side, which makes sense that the smoke would come out from there