egr code

i have a 1999 mountaineer 5.0 awd and the check engine light is on the computer code i got is p1400 which states egr sensor circuit low voltage detected. does this mean change the sensor or what any help would be appriciated.

dpfe sensor is bad - ford exteded the wantee on most of them for 2yrs/24k because they are junk - they even have a tsb for there dealer techs not to even do the pinpoint tests for egr codes - just replace the sensor because they are having so many problems