Sorry for shouting in this video. I was teaching in a large room full of people and needed them to hear me over the engine. This was an early video for me. I've gotten better. The tests in this video can be applied to any ground side controlled solenoid. You must know whether the solenoid being tested is ground or power side controlled. (Chapter 3 material in my Engine Performance Diagnostics book.)

To determine how the solenoid is being controlled watch this video:
How to test a computer controlled solenoid (power/ground side identification) https://youtu.be/kQz3g4HIWgs

Engine Performance Diagnostics chapter 3 pages 8-11

test shown enh 50

  • how to "be the computer" and energize the solenoid
  • how to test for solenoid function
  • EGR position sensor (EVP) signal test
  • EGR flow test by watching the reaction of the exhaust gas temperature sensor (EGT)
  • how to force vacuum to the EGR valve
  • how to test for plugged EGR passages.

Tools used

  • scan tool
  • back-probing tools
  • incandescent test light

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(Chapter 3) Transistors, Solenoids, Computer Controlled Output Testing

Related videos:

How to test a computer controlled solenoid (energizing the circuit manually) :


How to test a computer transistor driver (without a scan tool):


How to test a computer transistor driver (using a scan tool):


How to test a computer controlled solenoid (power/ground side identification) :


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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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