You have replaced the DPFE with a Ford one? Aftermarket ones are not so great at this... Have you replaced the EGR valve or just try to "clean" it?
P0401 - EGR Flow Insufficient Detected
The EGR system is monitored during steady state driving conditions while the EGR is commanded on. The test fails when the signal from the DPF EGR sensor indicates that EGR flow is less than the desired minimum.
EGR valve stuck closed
EGR valve leaks vacuum
EGR flow path restricted
EGRVR circuit shorted to PWR
VREF open to D.P.F. EGR sensor
D.P.F. EGR sensor downstream hose off or plugged
EGRVR circuit open to PCM
VPWR open to EGRVR solenoid
D.P.F. EGR sensor hoses both off
D.P.F. EGR sensor hoses reversed
Damaged EGR orifice tube
Damaged EGRVR solenoid
Perform KOER self-test and look for DTC P1408 as an indication of a hard fault. If P1408 is not present, look for contamination, restrictions, leaks, and intermittents.
Define "Crap" If you have crap that go in there then you have larger issues then just EGR codes. The EGR is a quasi closed system. It only routes a small portion of pre CAT exhaust into the intake after the TB. Any "Crap" would also be coating your catalytic converter and plugging the honeycomb or building up over time a thicker and thicker layer on the exhaust manifold.
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)