The check engine light is something most drivers dread. It can be orange, yellow, or amber; remain steady or flash; and indicate anything from a minor issue such as a loose gas cap or something major like a damaged catalytic converter. Formally known as the malfunction indicator lamp, the check engine light is a car computer’s way of letting you know something is wrong.

Part of a car’s onboard diagnostics system, the check engine light has been standard on automobiles since 1996, as part of the OBD-II protocol. Before then, engine diagnostics systems primarily existed to ensure EPA pollution control compliance. The light is usually just a picture of an engine, but may display messages like “check engine” or “service engine soon”.

When the light comes on, a trouble code is stored in the computer’s memory. This code identifies the source of the problem.

Reading the Computer’s Trouble Code

The check engine light indicates a problem that must be addressed. On the other hand, the maintenance required light, which is often mistaken for the engine indicator, means routine care such as an oil change is needed. The check engine light is an indicator of trouble.

Mechanics often charge a small fee for diagnosing the problem. You can also purchase a code reader online or from an auto parts store. By connecting it to the onboard diagnostics port, you can see the code that references specific components. Mechanics use this information to find parts that need to be fixed or replaced.

How to Decipher the Check Engine Light

The light can respond differently depending on the problem.

  • Blinking light: The problem needs immediate attention, such as an engine misfire causing unburned fuel to reach the exhaust system, which can damage the catalytic converter.

In some cars, the light will flash red. If a severe problem is indicated, reduce engine power and get to a mechanic as soon as you can.

  • Steady light: Although probably not an emergency, the car should be checked soon. It may still run the same, because car computers can compensate for many problems.

Still, the vehicle may be getting less gas mileage or emitting more pollutants into the air, such as hydrocarbons.

What Can Be Wrong?

When you see the check engine light, the problem can be with parts such as:

  • Ignition coils
  • Spark plugs
  • Oxygen sensors
  • Catalytic converters
  • Loose/faulty gas caps
  • Evaporative emissions purge control valves
  • Mass airflow sensors
  • Fuel injectors
  • Thermostats

Can I Drive with the Check Engine Light On?

In most cases, you can continue driving, but you risk serious and expensive damage to the vehicle. You can likely turn off or reset the light with a code reader. However, this doesn’t fix the underlying problem.

You should also not panic. First, check the gas cap. If it’s loose, an error message may be sent to the computer, but just tighten it. In other cases, get to a mechanic; aside from avoiding damage and expensive repairs, an active check engine light means you won’t pass a state inspection.

In short, when you see the check engine light:

  • Look for urgent problems
  • Tighten the gas cap
  • Reduce speed/load
  • Use built-in diagnostics

Lastly, seek maintenance at Hawthorne Auto Square if you purchased the vehicle from us. We multi-point inspect used vehicles before putting them on our lot, and provide after-sales service and maintenance as well. Whether you see the check engine light or are interested in financing popular-brand pre-owned vehicles, visit our Hawthorne, CA, dealership or call 866-707-7664 today.