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.
Ask Shawn Your Own Question
Shawn, Auto Service Technician
Category: Ford
Satisfied Customers: 3756
Experience:  16 years experience Ford,Nissan and Honda dealership in all areas
Type Your Ford Question Here...
Shawn is online now
A new question is answered every 9 seconds

05 Freestar. Code P0401. EGR valve, DPFE sensor and vacuum

Customer Question

'05 Freestar. Code P0401. EGR valve, DPFE sensor and vacuum reg are one unit. How do I check it. Haynes don't have it covered. Six wires to DPFE sensor. Pete
Submitted: 6 years ago.
Category: Ford
Expert:  Shawn replied 6 years ago.

Thanks for using Just Answer, I am sending you test procedures in pdf format, hope this helps you out.


P0401 - Exhaust Gas Recirculation (EGR) Flow Insufficient Detected

Description:The EGR system is monitored during steady state driving conditions while the EGR is commanded on. The test fails when the signal from the differential pressure feedback EGR (DPFEGR) sensor indicates that EGR flow is less than the desired minimum.
Possible Causes:
  • Vacuum supply
  • EGR valve stuck closed
  • EGR valve leaks vacuum
  • EGR flow path restricted
  • EGRVR circuit shorted to PWR
  • VREF open to DPFEGR sensor
  • DPFEGR sensor downstream hose is off or plugged
  • EGRVR circuit open to the PCM
  • VPWR open to EGRVR solenoid
  • DPFEGR sensor hoses are both off
  • DPFEGR sensor hoses are reversed
  • Damaged EGR orifice tube
  • Damaged EGRVR solenoid
Diagnostic Aids:Carry out the key on engine running (KOER) self-test and look for DTC P1408 as an indication of a hard fault. If P1408 is not present, look for contamination, restrictions, leaks, and intermittent faults.

Edited by Shawn on 1/6/2010 at 10:44 PM EST
Customer: replied 6 years ago.
Thanks for info so far, but some of the checks seem to indicate this is not for the one piece EGR/sensor/reg. There is no down stream hose, sensor hoses are part of the module and cannot be reversed or disconnected without it being very obvious. I want to check regulator (resistance) and supplies/returns at the six pin connector. Need to identify wires/ pins in connector. The dealer tech sheet has got me lost - different terminology is confusing. Please make it simple. Pete
Expert:  Shawn replied 6 years ago.

Here is some connector views and locations, hope this helps you out. Here are some more test procedures (CLICK HERE).




Edited by Shawn on 1/7/2010 at 6:23 AM EST