99 F150 401 Insufficient EGR Flow

CEL recently came on in my truck with a 401 code. I checked the forums here and the consensus appeared to be to change the DPFE (Differential Pressure Feedback EGR) sensor.

I looked at the old one. Checked the hoses to make sure they weren't cracked. The only odd thing was that one of the connections appeared to be corroded on the sensor (water/moisture) when I pulled the hose. I actually shook a few drops of water out of the sensor. Replaced the sensor with a new one. Erased the codes. Truck seemed to run good and have more power. However, next day CEL came back on. Have not pulled codes yet but betting that 401 is back. Of course, I'll verify that first but if it is the 401 code back again, any thoughts on where to go next? Truck is in excellent shape but does have 160k on it.

Update: Checked the codes again. 401 is back.

Thanks

I had the same problem with my F 150. The problem is a clogged EGR passages. You need to remove the throtle body and clean the 2 passages that goto the EGR Valve. they get carboned up after about 100000 miles and it sets a code that there is no flow to the EGR valve. Its a simple fix takes about an hour.

Did you use a ford dpfe or aftermarket one? I have heard some of the aftermarket dpfe sensors are not that good.