P0401 EGR Code

[hoobs1]

I have a 96 Ford Explorer which needs to pass an emissions test but I can't get rid of a P0401 code which is for insufficient EGR Flow. I have no other codes and no engine performance issues. I have come up with five things to try but don't know which one to start with:
1. Remove EGR Valve and look for carbon buildup
2. Remove and Replace EGR Valve
3. Look for a leak in the vaccum hose lines (don't have a tool to do this)
4. Remove and Replace DPFE sensor
5. Remove and Replace EVR Solenoid

Any other items I should consider? Any suggestions on which one to start with? This truck is old so easy and cheap is preferred!

 

[sjjones]

94 with code 327 and 332. After doing a lot of searching have come up with exactly the same laundry list that you have.

The DPFE sensor seems to be the most likely culprit from this forum; however, the Fort Enthusiast forum generally believes it is most likely carbon build up - which of course only takes time to remedy.

About a year ago I had my DPFE sensor replaced and it removed all my pinging. No CEL codes were showing, just pinging. Now, a year later, my pinging has returned and the two codes mentioned above have been coming on always just after a few miles.

With 140K on the X, seems it would be a good idea to check for carbon build up on the EGR valve ports - but I'm confushed just how this is done. Some say to just remove the EGR valve and clean the ports/holes with something small. Others say to remove the throttle box entirely and do it from that angle. Any suggestions most appreciated.

 

[rizzjc]

How to get to the EGR depends on the year and engine. On my '97 it was easiest to remove the intake, and throttle body and extension housing. You can clean it and test it off the vehicle. I have a P402 I can't get rid of, but yours sounds like it could be the DPFE or the EGR itself. I think a tear in the bladder would 'cause the 401 code.

On the '96 4.0 the DPFE seems like the best place to start, from what others have said. I just have an EGR sensor and replaced that, but it didn't help.

 

[Garth]

I have had the p0401 & p0401pd codes for quite awhile now. I change the egr valve first only because I had the code after I changed the flow tube which had rusted through. Still had the codes but only after hard excelleration or braking. The culprit in the end was the egr selonoids/sensor.

Had a vacuum leak because one of the tube connection had a crack.

Fixed.

 

[rizzjc]

That figures. I replaced the sensor first, and it was the EGR. You replaced the EGR, but it was the sensor. Murphy in action! ;-)

 

[wow97]

i have the same i have a 1997 ford explorer 4.0 ohv v-6 vin x with 5-speed automatic it has 4x4 auto 4x4 high 4x4 low a 150,000 i put new egr valve i find out the egr valve is cracked i said Doh! i put new
4. Remove and Replace DPFE sensor
5. Remove and Replace EVR Solenoid
6.remove and replaced three oxygen sensor
7. remove and replace maf and fuel rail gasket and o-rings
8. remove and put new egr valve one year ago it was running too lean but i unplug maf for 20min it ran back to normal i dont waste gas nomore woo-hoo