Your Ford Fusion's ignition system is a traditional coil-on-plug design. The system is extremely basic and runs on a 12-volt power source and a switching signal. It is connected by two wires. The Ford ignition control unit and engine computer directly regulate the switching signal, which instructs your Fusion Ignition Coil and Spark Plug when to fire.
You'll get a check engine code, or your idle will worsen if the ignition coil in your car has an issue. This article will help you examine your ignition coil if you experience spark issues with your 2.5L liter Ford Fusion SE. A check engine light on in your Fusion is one of the first indications that anything is wrong with your coil on the plug system.
You may use your steering wheel controls to go to the proper menu, or you can use an OBDII scan tool to obtain the stored DTC code.
A digital multimeter is required before you begin testing your Ford Fusion ignition coil. The 12-volt reference is the signal you'll be looking for, but first, we'll open your Fusion hood and locate your coils.
There are four coils here, and if your Fusion has a particular engine misfire code, start by identifying the problematic coil. You may start testing your Fusion Ignition Coil one at a time by disconnecting them one at a time.
Every single one of your Fusion ignition coil plugs has a two-wire connection. To disconnect, depress the locking pins on this coil harness and pull carefully.
The power cable will be the first to be examined. Enter your Ford Fusion key and turn the ignition to the "ON" position to verify this.
This should provide 12 volts to your ignition coil and power to all of your sensors.
Unplug the coil and connect your multimeter's black lead to the negative terminal of your battery. In the Fusion Ignition Coil wiring design below, carefully probe the front of PIN A.
With the key in the "ON" position, the wire going to PIN A should have a 12-volt power signal. The switching signal will now be checked, which must be done with the wire connector attached.
You must be cautious while testing the switching signal since it requires starting the engine. Make sure your parking brake is engaged, and your gearbox is in PARK or neutral. Keep your hands, clothes, and tools away from the cooling fans, drive belts, and engine.
The wire that goes to PIN B is, of course, the switching wire. As you crank your Ford, a switching signal should vary between 0-5 volts.
If you pierce the wire with your multimeter lead, you can easily test this component. While your engine is running, have a buddy try to crank it up and watch the signal at this wire. It's time to replace your Fusion Ignition Coil if it doesn't return these numbers.