GMC Repair: p0452 error code?, nitrogen system, replacement fuel

Question
First thank you for responding yesturday. Could this code be caused by an improperly fitting sensor in the fuel pump itself? On the replacement fuel pump the black sensor seems lose compared to the same black sensor on the original fuel pump? Also is the middle line on top of the fuel pump for the evap system? I did check connections last night and everything seems fine.

Answer
it could be leaking if that connection is loose, you will get that code if pressure is leaking from the tank.  Kinda hard to tell if it is leaking without pressure testing it, we have a nitrogen system that pressurizes the system and will emit smoke if their is a leak