Blog Car Care Advice Ford Check Engine Light On: 5 Likely Causes + What to Do Next
Car Care Advice

Ford Check Engine Light On: 5 Likely Causes + What to Do Next

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If you’ve ever driven a Ford, chances are you’ve had a moment of dread when that tiny Ford check engine light suddenly illuminates on your dashboard. 

But here’s the thing – ignoring that warning light is a bit like ignoring a toothache. It might seem harmless at first, but it can lead to severe and costly consequences. 

So, what does this check engine light mean?
And what should be your immediate reaction

Let’s uncover the mystery behind this warning light and answer some pertinent questions. 

This Article Contains:

Let’s dive in! 

What Causes a Ford Check Engine Light to Turn on?

An active check engine light doesn’t mean you need to hit the panic button immediately. Being a part of your Ford’s diagnostic system, this light could come on for various reasons — a faulty gas cap or a severe engine problem. 

Here are some common triggers: 

1. Loose Gas Cap

More often than not, a wrongly placed or worn gas cap (fuel cap) could be the problem behind that lit check engine light. 

But you shouldn’t ignore it!

A loose gas cap can let fuel vapors escape and reduce the fuel tank pressure. Likewise, it can allow dirt to enter the fuel system and clog a fuel injector. This will cause the fuel pressure sensor to trigger the warning light and your car’s Engine Control Unit (ECU) will register an error code. A bad gas cap will also affect your fuel economy down the line. 

2. Faulty Catalytic Converter

The catalytic converter is a part of your vehicle’s exhaust system that helps convert harmful exhaust gases into harmless ones. 

But if you don’t service your catalytic converter regularly, it can clog and fail, activating the check engine light. Your Ford’s ECU will likely register an error code P0420 or P0430. A damaged catalytic converter will also lead to poor engine performance, reduced fuel efficiency, and a failed emissions test. 

3. Faulty Oxygen Sensor (O2 sensor)

Whether you drive a Ford Escape or a Ford Fusion, all Ford vehicle ECUs rely on a sensor set to produce the right airfuel mixture for combustion. One of these is the oxygen sensor (O2 sensor.)

The oxygen sensor measures the amount of oxygen in the exhaust gases. However, a faulty oxygen sensor will misread this data and affect the airfuel mixture, triggering the check engine light and a related diagnostic trouble code. 

4. Mass Airflow Sensor 

Like the oxygen sensor, the mass airflow sensor measures the air entering the engine. But if the mass airflow sensor wears out, it can lead to issues like engine misfire, engine stalling, poor fuel economy, and an active check engine light. 

5. Worn Ignition Coil or Spark Plugs

The ignition coil provides the required voltage that helps the spark plugs generate the required spark. The spark plug wires deliver this current to their respective spark plug. The plugs then ignite the airfuel mixture for combustion. 

When you have a faulty ignition coil, worn spark plug wires, or your spark plugs are fouled, it can affect the fuel combustion. Consequently, your ECU will trigger the check engine light along with a diagnostic trouble code. 

Unburned fuel due to worn plugs or plug wires will also cause poor engine performance, reduced power during acceleration, and reduced fuel efficiency. 

5. Vacuum Leak 

The vacuum system is vital in lowering harmful emissions by routing fuel vapors back into the engine for combustion. However, vacuum hoses can dry out and crack over time, causing a vacuum leak problem. A surefire sign of a vacuum leak is high or surging RPMs during idle, along with an active check engine light. 

When one or more of these causes activates your Ford check engine light, it requires immediate action to salvage the situation. Let’s find out what they entail. 

What to Do if Your Ford Check Engine Light Turns On?

When you notice a lit check engine warning light on your dash, you must observe its pattern to determine your next action.

Here are the two possible scenarios: 

1. Engine Light Illuminates Under Certain Circumstances

You’ll usually notice the check engine light when you turn on the ignition. The light will, however, turn off after a few seconds. This is completely normal and nothing to worry about. 

But if the warning light stays lit, try to look for any change in your vehicle’s performance. If you experience any problem like hesitation, odd sounds, or vibrations, it means that some component is failing or is about to fail. If there’s no performance issue, a Ford service is due.

Either way, you should take your vehicle to a certified mechanic ASAP. 

2. Flashing Check Engine Light While Driving

If your engine light suddenly starts flashing while driving, it indicates a severe engine problem. You should pull over immediately and get your Ford vehicle towed to a service center. Mostly, the flashing check engine light is caused by an engine misfire, and ignoring it can be catastrophic. 

You may wonder, will the light turn off once the underlying issue is fixed? 
We’ll answer that next. 

Will the Check Engine Light Reset Itself? 

For every Ford model, be it a Ford Escape or Ford Fusion, the check engine light should reset once the issue triggering it is diagnosed and fixed. So, if the culprit was a bad O2 sensor, faulty spark plugs, or worn spark plug wires, the engine light should go off once you replace these parts. 

But if the light stays on even after the required repair, you’ll need to reset it. You can either ask a certified mechanic to delete the registered code and reset it using an OBD2 scanner or do it yourself by disconnecting the battery for a few minutes. 

Since it’s difficult to tell with absolute accuracy what could have triggered the CEL, you need a professional engine light diagnosis. Let’s find out how much the engine light diagnosis will cost. 

How Much Does a Ford Check Engine Light Diagnosis Cost?

Generally, you can expect to pay between $88-$144. Based on the registered check engine light codes and car inspection, the mechanic will give you an estimate for the required repairs or service. 

Now, it could be tempting to put off this expense and continue driving with a CEL.
But is it worth it? 

Is it Safe to Drive With a Ford Check Engine Light On? 

Well, it depends on the severity of the underlying cause. You can continue driving for a few miles if there’s a steady light due to a loose gas cap. But if you notice any performance issues, your next stop should be to a Ford mechanic to diagnose the check engine light codes.

However, if the light starts blinking, you shouldn’t continue driving. Pull over to safety and call for roadside assistance. 

Wrapping Up 

The check engine light is a standard dash light on every Ford model. It helps keep drivers updated about their vehicle’s health. So, if you noticed your CEL come on and are wondering whom to contact — enter AutoNation Mobile Service.

Our mobile mechanics will take care of your Ford check engine light right in your driveway. We are available seven days a week and offer 12 months | 12,000 miles warranty on every Ford service. 

Contact us to let our Ford mechanic diagnose and fix the engine light and put you back on the road in no time.