6 Causes of a Check Engine Light (Explained)

You're driving along, minding your own thing, when an orange light on your dashboard appears out of nowhere. The words "check" or "check engine" may appear next to it, and it resembles the shape of a car engine.


The check engine light is of the most infamous warning lights.


The good news is that your car's check engine light doesn't always imply something is wrong. The bad news is that the check engine light might indicate something is wrong with your vehicle.


check engine light

Why Is There a Check Engine Light?

The check engine light might illuminate for a variety of reasons. The warning might be triggered by something as simple as a loose fuel filler cap or as substantial as engine failure.


Significant issues, such as failing internal engine components may also activate the light. It's essential to have a professional analyse your automobile's problem to understand what's wrong.


Can It Come On for No Reason?

The check engine light can come on for many reasons. There is usually a reason, it may be something minor or something major.


Common reasons for a check engine light if nothing seems to be wrong is usually emissions related, such as a loose filler cap or a malfunctioning catalytic converter.


What Causes the Check Engine Light to Illuminate?

The check engine light might appear for a variety of reasons.


The warning light can activate when your car's computer identifies a problem with the powertrain (engine, gearbox, and associated components) that might result in higher exhaust emissions.


A defective gas cap, for example, might cause the light to turn on because gasoline vapours are escaping into the environment.


A misfire, hence higher emissions, may also turn on the light.


The check engine lamp might be triggered differently depending on the vehicle's year, make, and model.


There is no way to accurately explain why the check engine light is on without extensive analysis by a professional technician.


The check engine light illuminates when there are difficulties with the powertrain (engine, gearbox, and associated components).


For example, the ABS (anti-lock braking system) warning light will illuminate instead of the check engine light if your brake system is malfunctioning.


However, since multiple systems of a car are so interconnected, a failure in one subsystem (for example, the antilock brakes) might sometimes trigger alarms in another (such as the powertrain).


However, the CEL (check engine light) most likely indicates something is wrong with the powertrain.


Solid vs Flashing Warning Light

Whether the check engine light is steady or flashing, the significance might differ.


An engine check light that is both solid and flashing indicates a problem.


A flashing engine check light indicates a significant issue that could cause further damage. Therefore, you should have the vehicle investigated when you notice a flashing light to avoid substantial powertrain damage.


Certain cars' engine lights will not blink when the situation is critical. When a significant problem is detected, the warning light may become red or orange rather than yellow.


However, this is not the case for all vehicles.


Whether your check engine light is solid or flashing, you should always get your car examined and fixed.


Most Common Causes of a Check Engine Light

Let's look at some of the most prevalent reasons your check engine light is on.


There are many reasons, the reasons listed below are only some of the most common and is not a list of all possible causes.


1) Issues with the engine

Various factors, including engine issues, may trigger the check engine light. A cluster of sensors in a control module monitors engine functioning.


If a sensor reads data that is not typical, it may turn on the check engine light.


2) Problems with transmission/gearbox

The gearbox in your automobile transfers engine power to the driving wheels. A transmission malfunction may trigger a check engine warning light because the two components are so intertwined.


3) Issues with the emission control equipment

Onboard emissions technology is abundant in today's automobiles.


Examples of emission control equipment include:

  • Catalytic converter

  • Particulate filters

  • Exhaust gas recirculation system

  • Evaporate emissions system


Each component is intended to reduce exhaust emissions.


If an issue with one of these systems is detected, the check engine light will illuminate.


4) Electronic powertrain control module & sensor issues

A variety of sensors and modules control modern vehicle powertrains.


Furthermore, the modules connect through an extensive data network. Therefore, the check engine light might be triggered by sensors, modules, networks, or wiring problems.


5) Problems with air & fuel supply

The correct quantity of air and fuel is required to function effectively for your car's engine.


The control module will likely recognise when too much or too little of one or the other. The car's computer will then illuminate the check engine light.


6) Problems with the ignition system

The ignition system contains the spark plugs, coil packs, and other components required to ignite the air/fuel combination within the engine.


As you would expect, the control module keeps an eye on the ignition system. If a fault is detected, it will activate the check engine light.


Can Low Oil Cause a Check Engine Warning Light?

Some consumers mistakenly believe that the check engine light means their car is low on oil. However, a low oil level is rarely one of the causes for the engine check light to illuminate.


Low oil levels are a severe issue, but it will not usually cause your check engine light to illuminate. However, if another problem is caused by low oil, the check engine light may also illuminate.


The oil warning light on your dashboard, on the other hand, will illuminate. This warning light resembles an oil can with an oil drop flowing from the spout. If this light illuminates, your car may need more oil.


Is Driving With a Check Engine Light On Safe?

Keep a careful eye on the performance of your car. Ask yourself the following questions.


  1. Are there any unusual noises?

  2. Is it still running smoothly, or is it coming to a halt and surging?

  3. Has it lost power?

  4. Are there any strange smells such as burning or exhaust?


Even though the check engine light is up, it may be acceptable to continue driving to a safe spot if you don't notice anything strange.


If you decide to continue driving, proceed with care, drive slowly, don't use full throttle unless required, avoid hills, keep the RPMs low, and get it assessed and fixed as soon as possible.


Determining the Cause of a Check Engine Light

A mobile technician has the tools and equipment to determine what a check engine light indicates.


A diagnostic trouble code (DTC) is stored in the computer's memory when your car's check engine light illuminates.


When plugged into your vehicle's OBD port, an OBD scan tool can extract this diagnostic code, indicating the issue.


The cause for your check engine light turning on will not be entirely revealed by this code. Instead, it is a starting point for further troubleshooting and diagnostic testing to determine what's wrong.


P0001, for example, is an OBD code that indicates a problem with the circuit that connects your engine computer to your fuel pressure regulator on your engine's fuel injection rail.


However, this does not always determine the cause, as this fault code has several causes.


The engine check light should switch off automatically after the problem has been found and resolved. However, it may need more investigation if it does not turn off or returns.


Here's What You Should Do

You won't know what the check engine light indicates until an expert diagnoses your vehicle. It may be something minor, or it may be something substantial and could cause further damage.


If the engine warning light illuminates while driving, listen for unusual sounds, smells, and vibrations. If you notice anything, or if the car drives differently, it may be best to pull over somewhere safe.


However, if nothing seems to have changed, it may be safe to drive a further distance, such as home or to a garage.


Take no risks; if your check engine light comes on, have it checked out by a professional as soon as you can.

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