Why Your Engine Light May Be On

Did you just notice a yellow, orange, or amber engine icon with the words ‘CHECK’ underneath, on your dashboard? We call it the check engine light, and it indicates something is wrong with the engine. The issue could be minor or major, depending on what’s amiss with the powerplant.

In most cases, you’d end up at an auto workshop to have the issues fixed. However, it would help to know the reasons why the check engine light illuminates. Today, we will explain what this light means, the common reasons why it turns on, and the ways to turn it off.

The check engine light appears on the dashboard with an engine marked usually with the words ‘CHECK’ beneath it. The light's color may vary according to the manufacturer but the common ones are yellow, orange, and amber.

Being a crucial part of the vehicle’s on-board diagnosis system, the light pops up when it detects a problem with the powertrain, i.e. engine, transmission, and other related components. The issue in the powertrain could increase tailpipe emissions and illuminate the light.

However, telling what might be triggering the light is tricky without performing the diagnostic. As the modern architect of vehicles becomes complex and interrelated, a problem with another subsystem, such as the brake system, could also cause trouble with the powertrain. Visiting a mechanic can be helpful to identify the issue.

Although the check engine light may appear for several reasons, some common ones are:

1. Loose Fuel Cap

A loose fuel cap is the most common reason why the check engine light illuminates. The fuel cap is a significant part of the fuel delivery system; it prevents the gasoline fumes from leaving the tank. Furthermore, it keeps the entire fuel system under appropriate pressure.

Next time your check engine light emerges, check the fuel cap first before diagnosing for other issues. The cap could be loose or need replacement due to not having a tight grip.

2. Faulty Oxygen Sensor

Another cause of the check engine light could be oxygen sensor failure. The sensor has the task of measuring the amount of unburned oxygen in the exhaust system. When the oxygen sensor goes faulty, it reports an incorrect amount, and the engine burns more fuel than needed.

Moreover, a bad oxygen sensor may lead to fewer miles per gallon of fuel, as the vehicle loses its fuel economy. It may also be detrimental to the catalytic converter and spark plugs.

3. Bad Catalytic Converter

The catalytic converter may go faulty due to lack of maintenance and thus may trigger the check engine warning. A bad catalytic converter means your vehicle no longer cares for environmental friendliness because it is unable to convert dangerous carbon monoxide into carbon dioxide properly.

Furthermore, with a faulty catalytic converter, your car will function at a high temperature and deliver reduced fuel economy and performance. Without a suitably working catalytic converter, your vehicle will also not pass the emissions readiness test.

4. Faulty Spark Plugs and Wires

Another reason for the check engine light might be bad spark plugs and plug wires. Responsible for lighting up the fuel and air mixture in the combustion chamber, spark plugs are a crucial component of your vehicle. Likewise, the plug wires transfer the spark to the plugs from the ignition coil.

Overall, the effects of faulty spark plugs and wires are visible in terms of engine misfiring and subdued fuel efficiency and performance. Moreover, bad spark plugs and wires can damage ignition coils and oxygen sensors and clog the catalytic converter.

5. Transmission Issues

A vehicle’s transmission system is responsible to manipulate the engine's power and transfer it to the drive wheels. Highly interrelated, the engine and transmission systems work closely together, and an issue with one can cause havoc in another.

A problem with the transmission system can raise the tailpipe emissions and trigger the check engine light. Therefore, have the car checked for transmission issues immediately to avoid damage to your engine or other components.

6. Mass Air Flow Sensor Failure

If you’ve analyzed all the above issues and the check engine light remains, it could be due to the Mass Air Flow (MAF) sensor failure. The sensor is responsible to measure the air entering the engine and calculate the fuel it requires to function efficiently.

A faulty MAS sensor can harm your spark plugs, catalytic converter, and oxygen sensor. Moreover, a failed sensor can ultimately lead to a fall in performance and fuel economy. Therefore, have the sensor replaced right away if you detect this problem.

Now that we know the possible reasons for check engine light, the next logical question is - is it safe to drive with the warning active. As soon as the light illuminates, pay close attention to notice anything unusual with your vehicle. Your car must not chug and lose power or generate strange sounds.

If you don’t notice any such events, you can continue to drive your vehicle to a safe location. However, maintain a slow speed and avoid shifting gears too quickly. As soon as you’re at a workshop, have the vehicle examined straightaway to get rid of the warning light.

Final Words

Among many indicators and warning signs on the dashboard, check engine light educates about a possible problem with the engine. It is hard to tell a specific reason that causes it, so you may need to visit a mechanic to diagnose the issue. However, some common reasons for the check engine light include MAS sensor failure, faulty oxygen sensor & spark plugs, and transmission issues. Once you see this light, drive to a car workshop and ask the mechanic to inspect and diagnose the real problem.