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Discussion Starter #1
I know what to do on my car with this code but i have a question.

What would be causing it to clog so quickly?

I just cleaned it 6 months ago.

Any ideas?
 

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Trumpeter Extraordinaire
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I wouldn't suspect clogging. There's a few components in the system that can generate that code. If the channels are clear, and the EGR valve check OK, then it may be the DPFE sensor (EGR pressure sensor, in the generic sense), or even the EGR vacuum solenoid. The DPFE sensor has been a big culprit in EGR-related issues.

Here's a quick list of possible causes from the 1995 PC/ED manual:

HE70 DTC 1407: RUN KOER SELF-TEST
Diagnostic Trouble Code (DTC) 1407 indicates that continuous self-test has detected no EGR flow.

Note: If the fault is currently present, DTC 1408 will be output in Key On Engine Running (KOER) Self-Test.

Possible Causes:

EGR valve stuck closed or iced.
EGR valve diaphragm leaks.
EGR flow path restricted.
EGR vacuum hose off, plugged or leaks.
EVR VPWR circuit open.
EVR circuit to PCM open.
EVR circuit to PCM shorted to PWR.
DPFE sensor pressure hoses both off.
DPFE sensor VREF circuit open.
Damaged EVR solenoid.
Damaged DPFE sensor.
Damaged PCM.
 

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Discussion Starter #3
Ok I'll bite.

Where is this DPFE?
 

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Discussion Starter #5
Cool. Looks like a quicker look instead of pulling the EGR again.
 

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Discussion Starter #6
Ok bring a dead one back to life.

Cleaned the passages again. Wasn't as clogged as the first time. And CEL came back on.

How do I truly check the EGR?
EGR Sensor is a bunch easier to get to but I don't want to just start guessing and replacing until I get it.

Will KOER give me 1408 if in fact the Sensor is bad?
I've only done KOEO test with the 1407 result.
 

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Trumpeter Extraordinaire
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You can connect a hand pump to the EGR valve, and apply a vacuum. Listen for it to open and close. I'm not sure how definitive that would be - I've done it just to convince myslef the valve was ok.

P1408 in the KOER test just indicates the EGR No Flow problem is not intermittant, but a possible cause could be the DPFE sensor.

Also, a "No Flow" condition can be caused by a faulty vacuum solenoid (part #4 in the above diagram). I've replaced that a couple times when encountering P1407 codes....
 

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Discussion Starter #8
Thank you.

I guess I can start at the least expensive (and easiest) and move my way down.

I got a stupid ticket for not having current inspection and now have to get that code gone.
 

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Discussion Starter #9
# 2 in the picture.
Simple to test with a multimeter and a small battery. They tell you to use a 6 volt lantern battery. I chopped up a power supply that was running 3 volts.

Anyone interested in the test procedure let me know. I was goingto write it down better than my scribbles befor posting.
 

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Discussion Starter #11
I'll draw a picture.
 

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here i gots a procedure for the dpfe hook a scan tool to it it should read .60-1.00 plus or minus a few more than likely yours is reading .12 which i have seen alot of at the dealer were i work i just go ahead and replace the dpfe they always go bad
 

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IronChopz said:
Here's a quick list of possible causes from the 1995 PC/ED manual:

HE70 DTC 1407: RUN KOER SELF-TEST
Diagnostic Trouble Code (DTC) 1407 indicates that continuous self-test has detected no EGR flow.

Note: If the fault is currently present, DTC 1408 will be output in Key On Engine Running (KOER) Self-Test.
Thanks for posting this info and diagrams. I finally took action on my car after driving around with a CEL (P1407) for a couple of months. A KOER test showed P1408 (value out of range) as noted. I had the code cleared at my uncle's shop, got some B12 Chemtool at Chief's down the road, my cousin took the green hose off and then sprayed down there. It turns out that the EGR was not completely stuck, but it was responding slowly. I plan to spray it a couple of more times. I've turned the car on and off about 3 times since the code was cleared, and have logged about 180 miles since. The code didn't show back up in that time, but I'll see what happens when I start it again within the hour.
 

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IronChopz said:
If the channels are clear, and the EGR valve check OK, then it may be the DPFE sensor (EGR pressure sensor, in the generic sense), or even the EGR vacuum solenoid. The DPFE sensor has been a big culprit in EGR-related issues....
Damaged DPFE sensor.
BINGO!

I replaced the DPFE sensor with a new one from Dan Newman. The code has been clear for over a week now.
 
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