December 09, 2021 By Francis G. Pallarco

Check Engine Light: What it means and what to do

What Is It?

If you ask me, it’s the most dreaded and misunderstood dashboard indicator light as it could mean different things. This could range from a simple loose gas cap or either some specific part that needs repair or replacing. While it doesn’t necessarily mean immediately pulling over and having it towed, it still doesn’t change the fact that it needs to be brought to a professional auto repair shop to be checked as soon as possible. Just remember that opting to ignore the warning could cause further damage.

Why Does It Light Up?

Once the Engine Control Unit (ECU) senses a problem pertaining to the vehicle’s emissions control system, the Check Engine Light (CEL) turns on. By doing so, it automatically stores a corresponding “trouble code” in its memory. A diagnostic scanning tool allows the auto repair shop technician to retrieve the code, thus enabling them to pinpoint what exactly needs to be repaired or replaced. Since 1996, most major automakers standardized their On-Board Diagnostic Systems or OBD, stipulating a standardized list of Diagnostic Trouble Codes (DTC) and mandated that all vehicles provide a universal connector to access this information. The OBD port is normally located and accessed under the steering column.

Top 5 Causes of Check Engine Light 

Apparently, there are many reasons why the check engine light has lit up, but here are the top five reasons:

Oxygen Sensor needs replacing.

Loose or defective Gas filler cap.

Catalytic Converter needs replacing.

Mass Airflow Sensor needs replacing.

Spark Plugs or Plug Wires need replacing

What To Do

Here are some tips once the Check Engine Light (CEL) turns on

Observe: Check the gauges on your dashboard. Do they indicate that your vehicle is experiencing low oil pressure or overheating?

Check Your Gas Cap: Try tightening or replacing your gas cap. Sometimes a broken or misplaced rubber seal (on the gas cap) can trigger the “check engine” light.

Reduce Pressure: If you notice that your vehicle’s performance has decreased, reduce your speed and observe its overall performance.

Bottom Line

If the “check engine” light turns on, it will either blink or remain constant. Either way, the vehicle needs to be checked. A blinking light means a serious problem requiring immediate attention. If the light is steady, the problem is not an emergency, but should also be checked as soon as possible. Remember, the moment the check engine light comes on, be extra cautious on the road and bring the car to a professional auto repair shop as soon as possible. Let a professional read the code using a compatible scanning tool and handle the necessary repairs.


Did you know?

“The Check Engine light (CEL) used to be formally known as the Malfunction Indicator Lamp (MIL)


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