Mechanics

Ignition Coil Test

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Step by step guide on how to test an automotive engine's ignition coil and trigger, this article pertains to most ignition coil systems.

Difficulty Scale: 4 of 10

Begin with the car on level ground, in park with the emergency brake on.

Step 1 - Identify the type of ignition system to be tested, most cars, use a coil over plug (COP) type of system, there are several variations but all work on the same principal.


Coil Over Plug Ignition System

Step 2 - When checking for a misfire while the engine is still running, the fuel pump must be disabled to avoid accidental ignition discharge. Using the owners manual identify the fuse location.


Fuel Pump Fuse

Step 3 - Once the fuse is located use needle nose pliers or a fuse removal tool to remove the fuel pump fuse from the power distribution center (PDC.)


Removing Fuel Pump Fuse

Step 4 - Remove the safety from the coil electrical connector (red.) Some cars are not equipped with this feature.


Remove Ignition Coil Safety

Step 5 - After the safety has been removed, depress the electrical connector tab to remove the connector from the coil assembly.


Remove Coil Electrical Connector

Step 6 - Once the connector has been removed, located both terminals to be used for testing.


Coil Electrical Connector Terminals

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AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2014-07-28)