Ignition Coil Test

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


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


Please use our question form if you have a specific question about your car as we are not able to give you a full answer on this page.

Article first published (Updated 2015-01-11)