DPFE is silver rectangular box located beneath EGR valve. It has two hoses (one inbound and one outbound) and an electrical connector. As was said previously, the only way I know to test it is with OBD-II scanner.

If you haven't cleaned out the EGR passages behind the throttle body gasket, then I bet that is the problem. I had a P0401 last year and replaced the EGR, EVR, and DPFE, but the code remained.

Once I cleaned the passages, everything worked great.

See the following links for more info on this:

http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=trouble&Number=1717

http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=trouble&Number=10673

96 Contour SE Duratec V6 24-valve 2.5L ATX 108,000 mi. Replaced: crankshaft w/ DMD, EGR valve (clogged), EVR, DPFE, PCV valve, evap emissions hose & tube (cracked), window regulator (broken), LH & RH PCV tubes, UIM gasket (leak), ignition coil