Hey! I'm new here and have some issues... I had a few codes pop up 2 weeks ago... p402 and p403, I changed the DPFE Sensor and the hose going to it, and the codes cleared. The next day they both came on again and I replaced the EGR Valve itself, NOW P401 code is on and there is a humming noise coming from the motor, So I pulled the throttle body and housing off the EGR Valve off and cleaned everything spic and span! and replaced the DPFE sensor AGAIN.... still have the noise and the code came back on this Morning? ANY SUGGESTIONS????

2001 Ford F150 5.4 4x4

 

Make sure you didn't cross the hi and lo side of the hoses on the dpfe sensor. It sounds more like the actuator solenoid to me. Here is a link
to a very good , step by step process in checking the egr system.
Part 1 -How to Test the Ford EGR Valve and DPFE Sensor

 

From a lack of understanding you are throwng parts and money trying to get lucky.
If you have only a 401 code now, you did have some luck.
Clean or replace the vacuum regulator solenoid that passes vacuum to the EGR. It has a sponge filter under the round cap and be sure the valve internal to the device is free to move.
The noise likely is the EGR slowly leaking down after being operated.
The vacuum regulator is a 3 port device such that it needs to allow air to enter so the EGR can close again once it has been opened and needs to close. This is why there is a filter under the round cap.
Good luck.