My 02 F-150 scab with a 4.6 has the service engine soon light on. I checked the codes and I was getting a 0402 (EGR flow excessive) and a 0401 (EGR flow insufficient). I cleared the codes and after 3 hot/cold cycles the light came back with only a 0401, after about a dozen cycles it's still only 0401.

Reading old posts this is usually a faulty DPFE valve. How can I test the DPFE to make sure this is what's broken before I fork out $70 for a new one?

Also, are there any guides for removing the DPFE? It looks like there are two rubber hoses that attach to the exhaust recirculation pipe, but there aren't any clamps on these hoses so I'm guessing there's a trick to getting this off.

 

Unless you have the tools to test with, I would eliminate the other possible causes first then replace the DPFE if no other faults are found.
Key on, engine off and plugged up.

Pressure = 0 output = .45 volts..
............... .50 ......... .90 volt.
..............1.00 .........1.40.
..............1.50 ........ 1.90.
..............2.00 ........ 2.40.
................................... .
............. 3.00 ........ 3.30.
................................... .
............. 4.00 ........ 4.25.
............. 4.50 ........ 4.60.

Or tee a pressure gage in the down side hose and look at the output vs pressure seen in reference to the chart above.

Still want to do it?

 

Just replace it, I'm sure everyone on the forum knows about Fords famous dpfe problems. I replace at least on a week.

 

http://www.fordscorpio.co.uk/egrsensors.htm


Now you'll want to just replace it

 

I'd say 90% of the time code P0401 is a bad DPFE. It's the #1 fail item on Ford and Mazda trucks. Shop around. I normally pay less than $40 for them.

Big note on DPFE's. They have 1 "large" input and 1 "small" input. The new DPFE may have the inputs 180 out from the original. You mix them up and you'll still get code P0401.

 

I seen them @ Global Auto pretty cheap the other day -

http://search.stores.ebay.com/GLOBAL...271212QQsofpZ0


4th item up from the bottom - that's a good price but it's a roll of the dice - Ford updated these recently and the updated DPFE's can only be had at the dealerships..

 

cost me $85 and the problem went away. i didn't check it but i trusted the info on this site.

yup, 2 hoses, 2 10mm nuts and electrical plug...i think thats all. wicked easy, about 5 mins to do.

 

I bought one a year ago from a dealer in CT. for 35 + shipping.