Common Causes for Check Engine Lights

Has the check engine light turned on in your Ford? It can be alarming seeing an engine warning appear on your dashboard, especially if you've never seen it before. A wide array of issues can cause a check engine light to come on, some more serious than others. Fortunately Friendship Ford of Bristol is here to help you figure out what might be wrong, and what your next steps should be. Below we have highlighted the most common causes of a check engine light.


  • Loose Gas Cap: Your gas cap is loose, broken, or simply missing. Gas cap issues can reduce fuel pressure and allow fuel vapors to escape, reducing fuel economy and increasing harmful emissions.
  • Failing Catalytic Converter: Your catalytic converter can eventually clog with material, especially with higher mileage vehicles. The catalytic converter is a vital part of the emissions system, removing toxic carbon monoxide. A failing or clogged catalytic converter can severely impact fuel economy and vehicle performance.
  • Fouled Spark Plugs or Spark Plug Wires: Over time you will eventually need new spark plugs or spark plug wires. Your spark plugs create a hot spark that ignites the air-and-fuel mixture in the cylinder, allowing your engine to start and run. Faulty spark plugs or spark plug wires can cause your engine to misfire, reducing fuel economy, performance, and even prevent it from running altogether.
  • Faulty Oxygen Sensor: Due to long exposure to hot exhaust gas, your oxygen sensor might need replacing. The oxygen sensor provides vital air-fuel mixture information to the ECU. A faulty oxygen sensor can cause your vehicle's computer to supply the engine with too much or too little fuel. An engine with too little fuel is at risk of total engine failure, and an engine with too much fuel will create excessive smoke and odor.
  • Faulty Mass Air Flow Sensor: When exposed to dirty or particle-rich air, the Mass Air Flow (MAF) sensor could fail. Like the oxygen sensors, the MAF sensor measures the amount of air entering the engine and help ensure the proper air-fuel mixture. A faulty MAF sensor can cause your engine to misfire, ultimately causing poor fuel economy, performance, and potentially more unnecessary damage to your engine.

What to Do if Your Check Engine Light Comes On

No matter the situation, when the check engine light comes on in your vehicle, we always suggest stopping by our service center so one of our knowledgeable technicians can properly diagnose and repair your vehicle. Our service technicians have the most up-to-date diagnostic equipment that can quickly read OBD codes.

The way your check engine light is behaving though can help you determine what might be wrong with your car, and the severity of the issue. To help you better understand what you should do next, we've outlined possible scenarios:


  • The check engine light only comes on in certain conditions: If the check engine light is coming on intermittently, be sure to notice any changes in the performance of your vehicle when the light is on. If you do notice a difference, try driving your vehicle as little as possible until you can bring it in for service. Most likely something is on the verge of failing and you run this risk of your vehicle not starting again.
  • The check engine light is constantly on: Your vehicle's onboard diagnostic system has determined something is wrong and needs to be fixed. Although your vehicle may seem to be operating fine, it's best to bring it in for service as soon as possible to prevent additional issues.
  • The check engine light is on and there is a noticeable performance issue: If you are noticing a consistent decrease in performance with the check engine light on, your vehicle may have automatically entered a "limp-mode" to prevent additional damage. In this case, you should come straight to our service center or have the vehicle towed to prevent any damage to the engine.
  • The check engine light is blinking while driving: Not to be confused with the light occasionally flickering in the first situation, if your check engine light is blinking consistently that typically indicates there is a major issue with your vehicle and you should pull over when safe. If you are not close to our service center, we suggest having your vehicle towed here just to be safe.




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Ford Service in Bristol, TN

We know servicing your vehicle is just another chore, which is why the team at Friendship Ford Bristol is dedicated to making the process as streamlined and worry-free as possible.

From our factory-trained and certified technicians to our state-of-the-art service center, we will fix your car right, getting you back on the road and Driving Safe. Additional benefits include:


Complimentary Health Check


Vehicle Sanitization


Mobile Service Available



Ford Maintenance & Repair Services

Proper routine maintenance is critical in prolonging your Ford vehicle's life. Let our experts handle everything. Working on vehicles each day, Friendship Ford Bristol's technicians have experience servicing a wide selection of makes and models. As safe as they are skillful, all of our technicians are factory-trained and ASE-certified. Every Friendship location has a team of reliable experts on hand who are ready to provide you with unparalleled professional service.

Some services we offer include:

Ford Oil Changes

With old or dirty oil, your engine will not be performing at its best, reducing your fuel economy and shortening the life of your engine. By scheduling routine oil changes, you help keep your vehicle running at its best for years to come.

Ford Tire Rotation & Replacement

Tires play an essential part in keeping your vehicle safe and reliable. Our expert service technicians can replace or rotate your tires properly and have you back on the road in no time.

Ford Brake Service

Due to varying road conditions and driving styles, it's important to service your brakes and have them inspected regularly to keep you safe on the road. If you drive on worn brakes, you risk putting additional strain on your transmission and tires.

Ford Battery Replacement

Today's vehicles are loaded with technology. That's why it's more important than ever to ensure your battery operates at peak performance. Friendship of Bristol offers a complimentary computerized battery test and replacement batteries.

Ford Check Engine Light Diagnoses

A wide array of issues can cause a check engine light to come on, some more serious than others. No matter the situation, we always suggest stopping by our service center so one of our technicians can properly diagnose your check engine light and make any necessary repairs.

Ford Warranty Repair

When you purchase a new Ford, you are covered from defects in materials or workmanship that originated at the factory. If you encounter any issues, make an appointment at our service center so we can help to diagnose the problem and perform any warranty repairs.

Scheduling Service at Friendship Ford Bristol TN

If you are looking for a trusted Ford service center serving Bristol, look no further than Friendship Ford Bristol.

To get started, enter your vehicle information into our online service scheduler above, which will help determine recommended services. You will then be able to pick an available appointment time and set up reminders via email or text.

At your scheduled date and time, pull into our service drive, and one of our team members will greet you, go over any services you have planned, and answer any questions you may have.

If you have any questions about servicing your vehicle, you may also give us a call to speak with one of our friendly and knowledgeable service advisors. We look forward to assisting you.