Question

My 1999 Ford F150 4.2L has the code P1401, is this serious? How is it fixed?

Answer 1

DPFE - Differential Pressure Feedback sensor. It meassures the flow in the EGR tube and converts this to a signal for the computer. When it goes bad the performance and milage of your engine will drop.

The DPFE is on the side of the throttle body and it has two vaccuum lines attached to it. You may have to replace it there might be carbon build up there and also the EGR valve could have carbon build up.

If cleaning or replacing does not help changed the fuel filter and clean the MAF (Mass Air Flow Sensor)

Answer 2

P1401 FORD Code - DPFE Sensor Circuit High
Read more: https://www.autocodes.com/p1401_ford.html