2000 Chrysler Sebring jxi

I got a $100 diagnosis of fault code Po171 from my dealer and they concluded that the fuel pump needed replacing. It was at 35 psi where it should be 50 psi. They wanted $811 to replace it. Could this be any other fault? I had the fuel pump replaced 2-3 years ago. I am going to try to replace it myself but need to be certain that the fuel pump really is the problem. The reason I am a little skeptical is that the fuel pump was replaced only 2 years ago. Could this be a seal leak on the “in-tank pump” or other cause?