Learn the Top 5 Reasons
Why your check engine light may be on


The AutoZone Fix Finder*

An easy-to-use tool to troubleshoot why your Check Engine Light is on, Fix Finder utilizes an extensive database of repair solutions from ASE certified mechanics to help you get to the most likely fix.

How does AutoZone Fix Finder work?

  • Fix Finder pulls your vehicle information, code and mileage.
  • This data is analyzed to give you verified fix solutions for your specific vehicle from over 5.5 million ASE-Certified technicians' records.
  • These solutions are given to you in a FREE, easy-to-read MYZONE HEALTH REPORT.

Visit your local AutoZone store and let us help you find out if the problem is simple or serious

Your Check Engine Light may be indicating a simple problem that’s easy to fix – such as a loose gas cap. Or, it could be a warning of a more serious problem that could damage your engine components. Finding out why your light is on now can save you money and trouble down the road.

Find an AutoZone near you

Your Oxygen (O2) Sensor needs replacing

Your oxygen sensor measures the amount of unburned oxygen in your vehicle's exhaust system.

What if I don't replace it?

  • Your engine will burn more fuel than needed
  • You will experience loss of fuel economy (up to 40% if ignored)*
  • Faulty sensor(s) can cause damage to your spark plugs and catalytic converter



Gas cap is loose, damaged or missing

Your gas cap seals the fuel system and helps maintain pressure within the fuel tank. It also prevents gasoline fumes (hydrocarbons) from being released into the atmosphere while you aren't driving your car.

What if I don't replace it?

  • You can lose fuel through evaporation
  • You may make more trips to the gas pump

Catalytic Converter needs replacing

Your catalytic converter helps protect our environment by converting harmful carbon monoxide into carbon dioxide. Damage usually occurs due to neglected maintenance (reasons # 1, 4, and 5).

What if I don't replace it?

  • Your vehicle will not pass an emmissions test
  • You will experience reduced performance and fuel economy
  • Your car may run at a higher temperature

Mass Airflow Sensor needs replacing (MAF)

Your mass airflow sensor measures the amount of air entering the engine to determine how much fuel is needed to run your engine efficiently.

What if I don't replace it?


Spark Plugs or Plug Wires need replacing

Your spark plugs ignite the air/fuel mixture in the combustion chamber of your vehicle. The spark plug wires deliver the spark from the ignition coil to the spark plugs.

What if I don't replace it?

Of course, there are various other causes of an illuminated Check Engine Light. Finding out may help you save gas and avoid more problems down the road. Get in the Zone.

Doing a Simple Tune-Up

Shop Referral Program

Or if you'd rather have a pro handle it, we can recommend a Professional Mechanic with our Shop Referral Program.

Other Dash Lights

See what some of the most common other dashboard lights indicate and visit your local store to troubleshoot.