DPFE or Vacuum Solenoid
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Junior Member
Joined: Sep 2004
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From: Kentucky
DPFE or Vacuum Solenoid
I have a 1997 f150 4.6 L and need a little help. My ses light was on so I had the code checked which showed insufficient egr flow. I first bought a new egr and o2 and changed the plugs. This seemed to work for a little while, then after 100 miles the light came on again. I drove it for 500 or so miles before it started missing again. I just had the code read again and it showed the same code 0401 again! I pulled the TB and cleaned the 101% clogged egr ports. Then I took it into work and it ran fine for about 10 miles and then the light came on again and it started missing really bad and the light started flashing. Needless to say, I started reading the heck out of this site. I have once again put new plugs in it, checked all connections and airlines, and cleaned the IAC. I just test drove it and it still seems like it misses a little during driving but idles fairly smooth. Which part would most likely go bad due to an extended period of driving with clogged EGR ports...the DPFE or the vacuum solenoid? I am fairly certain that one of these are the culprit, but hate to buy them both! Any help would be greatly appreciated.
Member
Joined: Sep 2004
Posts: 17
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From: Corona, CA
It's most likely just a damaged plug or wire. Just because it's "new" doesn't mean it's "good". 
You might have cracked the insulator or gotten water down the hole...it's probably not a big thing.
A flashing Check Engine light means misfire. It has nothing at all to do with EGR.
If the misfire continues, the Chck Engine light will come on and tell you what hole(or holes) are misfiring.
You might have cracked the insulator or gotten water down the hole...it's probably not a big thing.A flashing Check Engine light means misfire. It has nothing at all to do with EGR.
If the misfire continues, the Chck Engine light will come on and tell you what hole(or holes) are misfiring.
Member
Joined: Nov 2003
Posts: 92
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From: Panama City, FL
Do a search on this site for ways to test the vacuum solenoid. You'll probably find out it is ok.
My guess is the DPFE sensor. They have a very high failure rate, and will cause the P0401 code. Go to AutoZone and pay half what FMC wants from you. The swap takes maybe 10 minutes. My 5.4L went through this, and I just got done talking with a buddy who is going through it with his Y2K 4.6L.
My guess is the DPFE sensor. They have a very high failure rate, and will cause the P0401 code. Go to AutoZone and pay half what FMC wants from you. The swap takes maybe 10 minutes. My 5.4L went through this, and I just got done talking with a buddy who is going through it with his Y2K 4.6L.
Member
Joined: Jun 2004
Posts: 24
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From: ohio
i had the same code on my 01 4.6l the dpfe fixed it. by the way you are talking though it sounds like you have another problem. Mine was missfiring and i ended up haveing a bad coil. easy fix but it will cost you about $100 so id get it looked at.