A new question is answered every 9 seconds

97 Taurus: 3.0L..Check engine light..EGR valve..the solenoid

This answer was rated:

Impossible EGR problem on 97 Taurus, Duratec 3.0L DOHC. Check engine light, code p0401 (insufficient EGR flow). The EGR valve was replaced last year, and in the last month I've replace the solenoid and the sensor. I checked the EGR tube, and I could see a slight build-up on the walls at the valve but nothing major. It's hard to check it good without taking it off, but I couldn't figure out how to get it off. What else could be causing this problem? My gas mileage is crap (16-18 mpg), but other than that the car runs fine. Also seems to burn oil, I don't see a stain from a leak. Thanks!



Thank you for asking your question on JustAnswer


The common reason for the code P0401 in most case is set due to a bad DPFE sensor. If you have replaced it and are still setting the code I would suspect you have restricted EGR passages in the throttle body. Run this test,


Check Key On, Engine Off (KOEO) voltage of the Differential Pressure Feedback EGR (DPFE) sensor. Voltage should be 0.5-01.2 volts.

If static voltage of the sensor is incorrect, check the circuits of the DPFE sensor before replacing it. The Brown/White (BR/WT) wire is a 5-volt reference signal. The Grey/Red (GY/RD) wire is sensor ground. The Brown/Light Green (BR/LG) wire is the sensor signal circuit.

With the engine idling, open the Exhaust Gas Recirculation (EGR) valve with a hand-held vacuum pump. The engine should act like it is misfiring on several cylinders and the DPFE sensor voltage should increase to greater than 4.0 volts.

If the engine RPM decreases severely, but the sensor voltage does not react properly, replace the DPFE sensor.

Slowly open and close the EGR valve with a hand-held vacuum pump to verify that the valve does not "stick" in its bore.

If the engine RPM does not drop severely when the EGR valve is opened at idle, remove the throttle body and gasket and clean the EGR flow passages of carbon.

Customer: replied 7 years ago.

I've got how to get the throttle body off, but how does the EGR tube come off? I can figure out how to get it disconnected from the back of the engine.


Also, when checking the voltages on the DPFE sensor, am I checking those with the connector on it? And what wire am I looking for that 0.5-1.2 volts on?



The brown wire is the 5 volt reference signel with the connector pluged in. There shouldnt be any reason to remove the EGR tube to clean the passages. If your removing it you will have to loosen the nut on the back side, see the picture I sent.



Customer: replied 7 years ago.
You don't recommend cleaning the EGR tube? I've had several people mention it, that's the only reason I asked. Thanks again for your help!
No its not like going to be plugged. If the DPFE is working properly then I would remove the throttle body and clean the passage.
Customer: replied 7 years ago.
Good, because that thing looked like it was going to be a pain to remove. Just one last question. Since my DPFE sensor is brand new (less than a week), what do I do if the voltages aren't correct? Could it be an ECM problem?
No you likely going to find the passages are plugged. Very common on the DOHC engine.
Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 32595
Experience: 23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
Ron and other Ford Specialists are ready to help you
Customer: replied 7 years ago.
Awesome, thanks!!
Your very welcome and thank you as well.
Ask Ron Your Own Question
Ron , ASE Certified Technician
Category: Ford
Satisfied Customers: 32595
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
Type Your Ford Question Here...
Ron is online now
How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

What Customers are Saying:

  • AlvinC answered a question about my Ford truck that only someone with an in-depth knowledge of his subject would have known what was going on. Rich D USA
< Previous | Next >
  • AlvinC answered a question about my Ford truck that only someone with an in-depth knowledge of his subject would have known what was going on. Rich D USA
  • Because of your expertise, you armed me with enough ammunition to win the battle with the dealer. They are installing a fuel filter and fuel pump at no charge to me. Molly USA
  • I needed help with my car on Saturday morning....got a response in 5 minutes, and it was the perfect solution. Thanks again to your service. Jason V. Kirkland, WA
  • I do know, after going though this with JustAnswer, that I can somewhat trust my mechanic but I will always contact you prior to going there. BR New Jersey
  • I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P Elm City, NC
  • used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future. David L. Richmond, TX
  • 9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much. Phil Marysville, CA

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

Meet The Experts:

  • Ron


    ASE Certified Technician

    Satisfied Customers:

    23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
< Last | Next >
  • http://ww2.justanswer.com/uploads/FO/fordguyu/2015-7-7_172556_onnieew.64x64.jpg Ron's Avatar


    ASE Certified Technician

    Satisfied Customers:

    23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
  • http://ww2.justanswer.com/uploads/MU/muddyford/2012-6-13_1204_1.64x64.png Chris (aka- Moose)'s Avatar

    Chris (aka- Moose)


    Satisfied Customers:

    16 years experience
  • http://ww2.justanswer.com/uploads/JM/jmcdo28/2012-2-23_01655_resized.64x64.jpg John Mc's Avatar

    John Mc

    Ford Technician

    Satisfied Customers:

    19 years Ford Lincoln Mercury experience
  • http://ww2.justanswer.com/uploads/wmarti7/2009-4-18_04332_Avatar.jpg Chuck's Avatar


    ASE Certified Technician

    Satisfied Customers:

    33 Years Experience,Ford Senior Master,ASE Master,L1 Advanced Engine Performance
  • http://ww2.justanswer.com/uploads/BL/Bluegorilla/2012-6-21_16298_cam.64x64.JPG Cam's Avatar


    Journeyman Automotive Technician

    Satisfied Customers:

    GM Grand Master Technician 2007. 14 years Automotive experience.
  • http://ww2.justanswer.com/uploads/CR/crzydrvr00/2013-11-3_12123_246347.64x64.jpg Richard's Avatar


    ASE Certified Technician

    Satisfied Customers:

    12 years at a Ford Lincoln/Mercury and Jaguar dealer as a technician and shop foreman.
  • http://ww2.justanswer.com/uploads/BA/baddad1/2014-4-1_23659_avatar.64x64.jpg Mike V.'s Avatar

    Mike V.

    Auto Service Technician

    Satisfied Customers:

    25 years experience on all makes and models, Licensed NYS Inspector.