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Common Causes of a Check Engine Light

Updated: Jan 9

The check engine light is of the most infamous warning lights, an orange/yellow light appears resembling the shape of a car engine, the words "check" or "check engine" may appear along with this warning light.

Sometimes it may simply be a sensor malfunctioning and be nothing to worry about, other times it may indicate a serious issue.


Table of Contents:

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What Is the Most Common Cause of Check Engine Light?

The most common cause of a check engine light turning on is a faulty oxygen sensor. This sensor measures the amount of unburned oxygen in the exhaust system, and if it is not functioning properly, it can cause the check engine light to illuminate.

Other common causes of a check engine light include a faulty catalytic converter, a malfunctioning mass airflow sensor, and a problem with the ignition system.

Why Does the Check Engine Light Come On?

Several factors might cause the check engine light to come on. Simple problems like a loose fuel filler cap or serious ones like an engine malfunction might set off the alert.

Serious issues might also trigger the light. To diagnose the issue, connect it as quickly as possible to an OBD scanner device to observe if fault codes display, then see a qualified mechanic for the outcomes.

Can the Check Engine Light Come On for No Reason?

The check engine light might illuminate for a variety of causes. There is typically a cause, whether it be a small or significant one.

If nothing appears to be wrong, common emissions-related causes for a check engine light include a loose filler cap or a malfunctioning catalytic converter.

Occasionally, a loose electrical connection or sensor might turn on the check engine light.

What Causes the Check Engine Light?

There are several potential causes for the check engine light to come on. For instance, if the computer in your car detects an issue with the powertrain (the engine, transmission, and related components) that might lead to increased exhaust emissions

If the fuel cap is broken or loose, fuel vapours may leak into the environment and trigger the check engine warning. It might potentially turn on due to a misfire and the resulting greater emissions.

Depending on the year, make, and model of the car, the check engine light may come on in a different way.

Without thorough investigation by an experienced technician, it is impossible to pinpoint the precise cause of the check engine light being on.

  • When there are issues with the powertrain, the check engine light will come on (engine, gearbox, and associated components).

  • If your braking system isn't working properly, the ABS (anti-lock braking system) warning light will turn on instead of the check engine light.

But since a car's different systems are so interconnected, occasionally a problem with one subsystem (such the antilock brakes) might trigger alarms in another (such as the powertrain).

However, the CEL (check engine light) most likely signifies a problem with the powertrain and engine.

Solid vs Flashing

The importance may change depending on whether the check engine light is on all the time or flashing. A problem is indicated when the engine check light is either solid or flashing.

A serious problem that can result in further harm is indicated by a flashing engine check light. In order to prevent serious damage, you should get the car looked at if the light starts to flash.