The OBDII DTC trouble code of P0303 is a misfire code for a specific combustion chamber in your Ford. In this particular case, we are talking about the P0303 OBDII code of Ford Cylinder 3 misfire detected. Today we’ll be showing you how to test your Ford Fiesta Ignition Coil in our 2014 Ford Fiesta ST with the 1.6 liter turbocharged Ecoboost engine.
This trouble code indicates that your Ford PCM has detected a misfire condition, which means cylinder #3 is not firing as it should. Symptoms can range from annoying to dangerous, depending on the cause of your misfire issue.
Other symptoms may include ;
- Engine doesn’t start easily
- Lugging or sluggish performance
- hesitating or bucking under throttle
- low idle or fluctuating idle
When you have a OBDII P0303 trouble code, you should always check the usual culprits. You should clear your OBDII Malfunction Indicator Lamp and see if this code returns. If this trouble code is intermittent, it can prove difficult to trace back or replicate.
If your symptoms persist and are a little more serious, as is the case with our Ford Fiesta, you should service your spark plugs, spark plug wires and ignition components. Because this vehicle is not driven by a distributor, we’ll be checking the igniter and the ignition coils to see if these are causing the problems.
Before beginning our How To Test Your Ford Fiesta Ignition Coil, you should open your hood and get your multimeter ready. Not sure on what a multimeter or voltmeter is or how to use one? Check out our guide here.
Begin this DIY article by opening your hood and undoing your engine cover. This cover can be removed by gently tugged downward toward the front of the vehicle, and then lifting up.
The next step in our How To Test Your Ford Fiesta Ignition Coil guide is to locate and unplug your Ecoboost Cylinder #3. This cylinder is the third over from the front of the engine, which would signify the number 1 cylinder.
Unplug this ignition coil connector by pulling out the white tab, and then depressing the retaining clip. With this ignition coil connector removed, you should see the standard three pin connector shown below.
It’s time to test your Ford Fiesta Ignition coil to see if there’s a problem with your engine harness wiring or the ignition coil. Take your multimeter and connect the ground to the negative terminal on your battery. Never test any electrical components using the engine harness low reference ground signal, as this can lead to ECU damage.
The pin you will be testing first is PIN A, which should be a 12 volt signal with the ignition turned on. To turn your 2014 Ford Fiesta to the “ON” position, have your key fob close and depress the “ENGINE START” button just once.
If you don’t have a 12 volt signal here, make sure your Fiesta is set to the ON position meaning the engine sensors are being powered. The next wire you’ll be checking is PIN B which represents the low reference ground signal your ignition coil needs.
If you do not have power or ground at either of these pins, you will need to trace back the wiring to your ECU to see where there is a damaged or broken section of wire. Check the wire connectors for any fraying or if there’s wire that’s exposed to the elements. Simply cut out and replace the wire in question to restore power and ground to your ignition coils.
If you have power and ground but your ignition coil is still malfunctioning, you should replace your Ford Fiesta Ignition coil using our DIY guide. If this How To Test Your Ford Fiesta Ignition Coil guide does not resolve your P0303 trouble code, make sure your exhaust does not smell bad or like rotten eggs.
This smell can be indicative of your primary upstream catalytic converter failure, replace your catalytic converter to solve your misfire issue. Have any questions about our How To Test Your Ford Fiesta Ignition Coil guide? Leave them for us below!
