nt Fuel Pressure Sensor signal

[rgreen]

After changing the gear pump and lift pump. Insite shows that After Treatment Fuel Pressure Sensor signal is 0 volts. Insite was showing this senor at 0 volts before I change everything. What does this senor effect on the engine? The truck starts fine., There is no more white smoke coming out of the pipe. I have also change the crankcase filter but I have read on the forum where someone drill holes in the case, if so can someone explain what I need to do to my case. I also have a crankcase pressure signal at 0 volts on Insite.