Kind of new here. Trying several different places to get some educated help. I'm hoping someone in here has come across some of these issues and point me in the correct direction.
Question for the troubleshooters... My daughter has a 2001 Ranger 4x4 4.0. She has thrown various codes for a while now, all with the emissions stuff. I have changed the DPFE. Then I found a vacuum hose that was dry rotted to crap. Changed that. Those codes, P0401 and 442 have gone away. Now, I get P0455. Everything I can read up on and YT says it is likely the vent solenoid on the carbon can. Changed that. Just before changing it, another code popped up, P1400. Changed the vent solenoid. Still getting the P1400. I pulled the DPFE, blew it out and a small spat of water came out. Blew out the 2 lines going to it. Ran the truck for a minute without the DPFE attached. No moisture blew out. Put it back on. Reset codes, P1400 comes right back on. So, any suggestions on what to do next? Thanks

 

Exhaust system has water vapor in it, a by-product of burning gasoline(H) with Oxygen(O) is H2O(water), this is why exhaust systems rust from the inside out and why tail pipes drip water

This is why the DPFE had water in it, it has two hose that connected to exhaust pipe, EGR pipe, and DPFE cools off faster than the exhaust so water vapor condenses in side it, and its hoses
Normal failure of DPFE is because of water inside which eventually corrodes it
If an engine is only run for a short time, under 10minutes, it doesn't have enough time to heat up all the parts to get rid of the old water vapor, so it acumulates


P1400 Diff Pressure Feedback EGR Circuit Low Input
Make sure you got the hoses back on the correct way, one is larger than the other, and that the hoses are also free from water and have no leaks

Here is some info many don't know about clearing codes and resetting the engine computer: Ford Motor Company Driving Cycle

Emission codes often won't go away after you clear them, they need to be cleared by the computer after drive cycle tests

You don't have to have the OBD reader hooked up to do these tests, computer will do them regardless, to test the systems after a reset

 

Thank you. I pulled the DPFE again since the light hasn't gone out after several days. It had water again. My daughter drives it back and forth to school, a good 20+ minute drive each way. There are occasions that she only drives less than 10 minutes to a store or something.
Yeah, only one way for the DPFE to go on. I checked the EGR valve to make sure it was clear and working. I made sure the two hard pipes to the DPFE were clear. I blew air through those pipes also in case anything was dislodged while checking them. I sprayed electrical contact cleaner into the DPFE and blew it out, several times. It would help any moisture dissipate. After getting everything back together, resetting the light, it stayed off. I was just told that late yesterday, the light came back on. It was off for about a day. I will assume until I check, that the same code came on and moisture is back in the DPFE.
So, moisture happens. What do I need to do to stop the code from happening? I can't be the only one with moisture... I'd rather not spend another $40-50 on another DPFE to find out that isn't the issue...

 

Make sure the hoses run "downhill" from DPFE to EGR pipe, so the condensing moisture can drain into EGR pipe

Any moisture in the hoses will be pushed up to the DPFE on start up but should be sucked back out during driving, around 2,500rpm, via scavenging exhaust suction

All exhaust has water vapor and if the incoming air is humid then even more water vapor in exhaust

The faster a part cools off the more condensation it will collect, the hoses and DPFE cool off faster than the EGR tube and exhaust manifolds

You could get 4 couplers that change hose size to a larger size, as large as possible
Install a short section of the larger hose just below DPFE and have it bend so it has a Low spot for water to collect, but not a tight bend, so water won't block the pressure in the hoses

This is a pressure reading system so size of the hose doesn't matter as long as fittings are tight/snug, the water blocks the pressure reading ability and causes code to be set