The ignition system in your Ford Fusion is a classic coil on plug system. Connected by two wires this system is very simple and works on a 12 volt power supply and a switching signal. The switching signal tells your Fusion Ignition Coil and spark plug when to fire, and is controlled directly by the Ford ignition control unit and engine computer.
When the Fusion ignition coil in your vehicle encounters a problem, you will get a check engine code or your idle will suffer. When you have spark problems with your 2.5 liter Ford Fusion SE you can use this guide to troubleshoot your ignition coil.
When your coil on plug system has a problem, one of the first signs of trouble is a check engine light on in your Fusion.
When this occurs you can use your steering wheel controls to flip to the right menu, or use a OBDII scan tool to retrieve the stored DTC code.
Before you get started on testing your Ford Fusion ignition coil, you’ll need a digital multimeter. Not sure what that means? Check out the guide here. The signal you will be checking is the 12 volt reference but first we’ll open your Fusion hood and find your coils.
There’s four coils here and if you have a specific engine misfire code stored in your Fusion, find the problem coil first. You can begin testing your Fusion Ignition Coil one by one, so start unplugging the coils first.
All of your Fusion ignition coil plugs are a two wire connector. Depress the locking pins of this coil harness and pull gently to disconnect.
The first wire you will be checking is the power wire. To test this you will need to insert your Ford Fusion key and turn the ignition to the “ON” position.
This will send power to all of your sensors and should send 12 volts to your ignition coil.
Unplug the coil and put the black lead of your multimeter to the negative terminal of your battery. Now gently probe the front of PIN A in the Fusion Ignition Coil wiring diagram shown below.
The wire coming to PIN A should have a 12 volt power signal with the key set to the “ON” position. Now you will be checking the switching signal, which must be done with the wiring connector attached however.
To test the switching signal, you need to be careful because it involves starting the engine. Make sure the transmission is in PARK or neutral, and that your parking brake is engaged. Keep your hands, clothing and tools clear of your engine, your drive belts and the cooling fans.
The switching wire is of course the wire that leads to PIN B. This is a switching signal that should fluctuate between 0-5 volts as you crank your Ford.
Testing this part is easy to do if you pierce the wire with your multimeter lead. Have a friend try to crank your engine and monitor the signal at this wire as your engine is running. If your Fusion Ignition Coil doesn’t return these values, it’s time for a replacement part.
Have any questions about your Fusion Ignition Coil or our guide on how to test one? Leave us a message below and let us know!
