DPFE Problem

I am having yearly failure on DPFEs.
I did the Isolator Bolt change in Nov 2007. Then a month later I had CEL P0401. Changed the DPFE, the problem went away. Then the same code came in Jan 2009 which was approx 13 mths after the change. Now I have the same CEL came up after 11 mths.. Could some thing else be causing the failures or just bad DPFEs ?

It cannot be the DPFE again.
It may be the EGR valve or clogged EGR port/hose. You may need to clean them.

Yes, it could be the DPFE again. I had a similar issue: Did the isolator bolt fix - and DPFE showed up a short time later.

Replaced the DPFE, but about a year later, the DPFE code showed up again. Replaced it again - and it failed again within six months.

My mistake: Not all DPFE's are created equal. I've had rotten luck with after-market DPFE's (metal or plastic case; neither seem to last very long). I finally broke down and bought a real Ford OEM DPFE (I used http://teamfordparts.com); all has been well since then.

BTW, I also checked the EGR ports, as well as the valve. Neither seem to clog up on my '00 the way I've read of them clogging on other model years.

EGR valve seems to be quite reliable on the Windstar.
I would also recommend the new DPFE.....why?......replacing it seems to solve the problem for a short time....if the problem were caused by something else, then I would expect that replacing the DPFE would not solve to problem.

It is understandable to wonder, as you have.....why you have to keep replacing the same part over and over.

Just like phil-l's van, mine too is 2000 yr. When I did the isolator bolts, I cleaned the EGR ports in the intake pretty good. The two hoses connected to the DPFE were changed with the first DPFE change about two years ago and are still very snuggly and tight fit. I just bought a new DPFE from Autozone for $55.00 with 2 yrs warranty. The previous ones were from Adv Auto and had different markings. Hope to have a better luck. Let's see.

You can check your DPFE to see if it's good or not:

*unplug DPFE sensor, turn key ton ON and check reference voltage on DPFE connector. It should be between 4 and 6V if it's good. It's pin at top when clip is on your left. If it's not, it may be the PCM that doesn't work correctly.

*Check also signal voltage on the bottom pin of the DPFE sensor (not connector) when engine is running. When engine is cold, voltage must be between 0.2-0.7V. When it heats up, EGR actvates, so voltage must be between 4-6V (like reference) if it's good.
If it's too low, then the DPFE is the problem.

Did your engine run roughly or stall sometime? Or overheat/knock? If not, you don't need to do anything.

serge, thank you for your valuable information. I have printed it and will keep it with my manual book.
Last week the CEL P0401 just came on. No indication of rough idling, knock or stall, nothing. I erased the code and it came back within 30 miles of driving. Bought a new one from Autozone and replaced the old one. No CEL for 3 days and 100+ miles driving.
I needed to get this CEL fixed as my inspection is due this month. Lucky Canadians only have to do this when ownership changes. It's annual here.
Thanks any way.

P0401 (no EGR flow) can also be cause by clogged EGR port or vacuum leak on EGR vacuum line.

Lucky Canadians only have to do this when ownership changes. It's annual here.
Thanks any way.

We never need to do this, even when ownership change. Mine have bad catalyst O2 sensor, and I'll never repair it. I drive only 1500 miles/year, I'll create an impact on environment.

Serge, when I lived in Ontario for many years, you could sell your vehicle "as is". But the new buyer had to get it inspected to change the ownership. Obviously, you get higher price if you get it inspected before you put it in the market. May be it is different in Quebec...........any way thanks for you help on this and many other threads.