The testing procedures shown in this video apply to all electronic style EGR systems. In particular the 5-wire Linear EGR valve used on many different GM vehicles. The car being tested has a 3100 engine in it. (3.1L)

This engine is notorious for have problems with plugged EGR passages in the intake manifold. Also these electronic EGR valves will stick in both the open and closed positions.

Engine Performance Diagnostics chapter 3 (solenoid test) chapter 7 (position sensor test) and chapter 24 (flow test)

symptoms 50

  • Check engine light (P0401)
  • "pinging" under load

fix 50

  • cleaned out restricted EGR intake passage

test shown enh 50

  • how to test a 5-wire electronic EGR valve
  • how to manually energize the EGR valve
  • how to energize the EGR valve with a scan tool
  • how to test EGR valve position sensor signal with a voltmeter
  • how to determine EGR solenoid polarity with a wiring diagram
  • how to determine EGR solenoid polarity with a voltmeter
  • how to check the EGR passages for a restriction
  • how to test and clean the EGR valve

Tools used

  • digital multi-meter
  • incandescent test light
  • pocket screwdriver
  • jumper wire
  • back-probing tool
  • mechanic wire or old coat hanger

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(Chapter 24) EGR Flow and System Tests

Related videos:

New EGR Valve still setting a P1404 trouble code (GM):


Ford Ranger EGR Flow Trouble Code P0401 (DPFE fault):


Ford EGR Flow Testing (P0401, P0402, P0405):


How to test an electronic EGR valve (GM P1406 case study):


Ford EGR flow quick test (P0401) DPFE fault:


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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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On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!