This case study is perfect for anyone interested in the working details of Toyota/Lexus coil over plug ignition system, and the very similar three-wire designs used by many other manufacturers. We spend a lot of time with the Pico on this one, but don’t forget the other basic checks I discuss, including the spark output, power balance and moving a suspected bad coil to another cylinder.

Engine Performance Diagnostics chapter 22

symptoms 50

  • check engine light (P0304)
  • misfire

fix 50

  • replace the #4 ignition coil

test shown enh 50

  • how to perform a cylinder drop test (power balance test) to identify a misfiring cylinder
  • how to perform a relative compression test
  • how to perform a spark output check on a coil over plug ignition coil
  • understanding three and four-wire coil circuit design and operation
  • understanding Toyota IGT and IGF circuits and related trouble codes
  • how to scope test a COP coil using voltage and current
  • analyzing coil current waveforms and IGT/IGF signals
  • identifying differences between factory and aftermarket ignition coils

Tools used

  • scan tool
  • incandescent test light
  • Pico four channel automotive lab scope
  • low amp probe

end faq

{accordionfaq faqid=accordion15 faqclass="dotluvfaq help2 aligncenter headerbackground headerborder contentbackground contentborder round7" active=item0}


(Chapter 22) No Spark Troubleshooting, Ignition Coil & Module Testing

Related videos:

How to test an ignition coil with a test light (Nissan C.O.P design):


How to test for a shorted ignition coil with a scope (Lexus):


Ford 5.4 shorted coil primary winding and bad computer driver:


How to test an igniter on a Toyota/Lexus:


Ignition System Designs, Operation and Testing (an SD Premium video):


end faq

{accordionfaq faqid=accordion3 faqclass="darkhivefaq defaulticon headerbackground headerborder contentbackground contentborder round5" active=item0}

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.

Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium. There is a 14 day free trial.

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!