The testing procedures shown in this video can be applied to any Ford, Lincoln or Mercury that uses a vacuum controlled EGR valve combined with a Delta Pressure Feedback EGR sensor (DPFE).

The vehicle being tested is a 2000 Ford Expedition with a 5.4L engine.

Engine Performance Diagnostics chapters 3 (solenoid test), 8 (pressure sensor test) and 24 (EGR flow test)

symptoms 50

  • Check engine light (P0401 Insufficient EGR flow or P0402 excessive EGR flow)
  • possible detonation or pre-ignition "pinging" complaints

fix 50

  • faulty DPFE sensor
  • restricted intake passage for the EGR valve (the exhaust side of the EGR is almost never the issue, only the intake side will plug up with carbon)
  • remove EGR and throttle body for typical cleaning of the passages

test shown enh 50

  • How to identify solenoid circuit design (power or ground side switching)
  • How to manually energize the EGR solenoid (EVR) and force the EGR valve to open
  • How to determine if the EGR passages are clean
  • How to test the DPFE sensor for proper operation
  • How to test the computer transistor driver for the EVR solenoid

Tools used

  • scan tool
  • incandescent test light
  • digital voltmeter

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(Chapter 24) EGR Flow and System Tests

Related videos:

Ford EGR flow quick test (P0401) DPFE fault:


How to test for EGR flow problems (GM electronic EGR test) - P0401:


How to test a Ford DPFE sensor (2007 Ford Taurus 3.0):


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For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available as an eBook or paper book.

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