I have a 1998 Ford Triton V-10 Superduty. At 42,000 mile the service engine soon light came on. I scanned the system and came up with code PO401. I was told that the DPFE sensor is a common problem so I went to autozone and got a new one. I changed out the DPFE sensor and blew out the lines going to it, and in about 200 mile get the same code again. It would seen at 42,000 miles this should not be happening. Any Ideas? Thanks

 

I had that code once, dealer diagnosted it turned out to be a dirty fuel filter. Replaced, no more light.