There's a way to test just about anything under the hood. These tests can be done with VERY INEXPENSIVE testing equipment/tools. Hopefully this article has shed some light on just how easy it is to test these Coil-On-Plug ignition coils (with two wires in the connector) with some very basic tools.

In summarizing the key points of this entire article (of testing a Coil-On-Plug system), they are:

  1. Test for spark first, test for power second, test for the Switching signal third.
  2. The spark is done with an HEI spark tester for true results.
  3. A test light or multimeter can be used for the power test.
  4. An LED light can be used to test for the Switching signal.
  5. That these tests are easy.
  6. No scan tool is required.
  7. That knowing working theory will help you diagnose a Coil-On-Plug ignition coil (with two wires in the connector) of any make and model with such a Direct Ignition System.

These very simple tests have made the difference (for me) between successfully diagnosing the no-start or misfire condition and making a paycheck or not. They will help you too. After all, I have been using these testing tips and techniques everyday for years.

Testing ignition systems, whether they're distributor based, or Direct Ignition (coil pack or Coil-On-Plug types), all follow pretty much the same rules and their testing methods are also pretty much the same.

To see this, I recommend reading the two case studies in this tutorial that go into detail about this. They are:

These other articles are worth exploring:

  1. No Start Testing And Diagnostic Basics
  2. Automotive Diagnostic Tips And Techniques: The Ignition Coil
  3. Ignition Coil Pack Testing Tips And Techniques
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