What Does The Service Engine Soon Light Mean?

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service engine soon light

What if you’re thinking about going out for stress relieving drive, just wanted to drive around, or have an important meeting, or just something you need to do and go, and your hands are yearning to switch on the engine.

But, when the engine starts to crank to life, you see a vivid glint in your center console. You examine it more closely and realize it reads, “Service Engine Soon.”  Initially, you may worry, be frustrated, and think, “Oh no, what’s wrong? Not now!”

The Service Engine Soon light is frequently confused with the Check Engine light. The Check Engine light on your dashboard often indicates that there’s something wrong with your ride. However, the Service light indicates that your vehicle’s scheduled maintenance is near.

You may believe that Service Engine Soon light does not require concern with this distinction in mind. Actually, you shouldn’t be too concerned since this is only the car’s way of politely asking you to bring it in for a consult.

However, it is frequently the simple things that trigger significant car repairs. In this article, we’ll be discussing the Service Engine Soon light; continue reading to learn more about this warning light, the guides, what it implies, and what you should do.

What Is Service Engine Soon Light?

You might have spotted the Service Engine Soon light is on, right before your eyes. Now is the moment to comprehend what is going on and what it means. Additionally, this light may appear without obvious symptoms or indications of trouble.

There are no strange feelings, noises, vibrations, odors, or leaks emanating from the vehicle. However, the most vigilant among you may have an extra sharp sense that the automobile’s status is slightly out of line.

However, it is more than enough to leave one question whether something is wrong. To begin, we must determine what the Service Engine light means and why it’s on. An electronic computer controls almost every modern cars’ engine.

These are sometimes referred to as the ECU (Engine Control Unit) or ECM (Engine Control Module). They are comprised of a tiny computer installed inside the car’s engine compartment of your vehicle. It is enclosed, much like the black box of an aircraft.

The ECU is then linked to various sensors throughout the vehicle and its critical components. These sensors can sense and analyze the car’s internal workings to ensure that everything operates correctly. Each part of your vehicle has its limit and is optimized for operation in one of its pre-defined states.

The sensors are all in charge of tracking them and directing other components to act in conjunction with them, for instance, the sensor’s ability to determine the coolant level and temperature, gas pedal positioning, fuel level, and so on.

If, for example, any of these parts operate at an abnormally high or low temperature or show symptoms of failure, the sensors will warn the ECU. When the ECU detects trouble, it will notify the driver. Based on the car model, this is accomplished through the Service Engine light or Check Engine light.

Check Engine vs. Service Engine Soon Light

As stated above, we learned that problems with the vehicle might generate a warning light on the dashboard with the help of sensors and the ECU. Another misunderstanding is that automobile manufacturers sometimes mix the Service Engine Soon light and Check Engine light. As a result, many individuals conflate these two distinct indications. Below, we’ll emphasize the basis of what distinguishes these two lights. Here are the distinctions in further detail.

The Check Engine Light

In contrast to the soft warning associated with the Service Engine Soon light indicator, this one seems more like a strong beep. The Check Engine light has often been the cause of uneasiness since it typically signifies a severe problem with your automobile that requires quick treatment.

This might indicate that a component of your vehicle is deteriorating or damaged, and you must get it inspected immediately. This frequently refers to parts of the vehicle that operate the engine. Occasionally, this might be an indication that a sensor has failed. As previously stated in our discussion of a Service Engine Soon light, your car’s sensors are vital. It guarantees that all components of the vehicle operate at their best rate.

The Service Engine Soon Light

Like the term implies, the Service Engine Soon light indicates when your vehicle is due for routine service and maintenance. It illuminates in words, showing “Service Due” or “Service Engine Soon.” However, it may also illuminate when there are minor difficulties with your vehicle that are not threatening and requires urgency, for instance, a loose or faulty gas cap.

That’s why, if your automobile activates such an indicator light, you may never notice any strange changes in your car’s performance. Car manufacturers can configure the Service light to illuminate after a specific range of miles or based on the last time the vehicle was serviced. Even the most sturdy automobiles are prone to wear and tear.

Usual Causes of the Service Engine Soon Light

Several circumstances in which the service engine soon light is certain to illuminate. While this varies significantly across many carmakers, the underlying reasons are frequently similar amongst automobile types. The following are some possible reasons for the service engine soon light.

Scheduled Service and Maintenance Alert

Every vehicle needs routine maintenance after a certain length of service, distance, or use, for instance, due to changing its engine oil. The Service Engine Soon light is specifically designed to remind of scheduled service and maintenance.

However, suppose your Service Engine or Check Engine light appears due to a service made. In that case, it is likely to be accompanied by another indication based on the brand of your automobile—for example, a low tire pressure light, a low oil, low coolant light.

Faulty or Loose Gas Cap

This is the most straightforward problem that might activate the Service Engine Soon light. The same with the Check Engine light, since the car’s ECM or ECU can detect a defective or loose gas cap and a leaking gas tank.

Low Fluid Volume

Every automobile contains proper quantities of fluids to ensure that everything operates appropriately and protects from wear and tear. Such as engine oil, transmission fluid, brake fluid, and coolant are just a few fluids included within a vehicle. If the quantities of such fluids are pretty low, the Service Engine light may activate.

Failing or Dirty Spark Plugs

A damaged, deteriorating, or even dirty spark plug might result in poor engine performance, like misfiring or slow acceleration. Additionally, it might result in greater fuel consumption or the vehicle failing to start correctly. And, of course, the poor condition of your car’s spark plugs might not only require new spark plugs, but it’ll also illuminate either the Check Engine or Service Engine Soon light.

Faulty Mass Airflow Sensor

This is a vital component of every contemporary car. Its purpose is to determine the amount of air going through the air filter. If the mass airflow sensor or MAF sensor is functioning correctly, it will inform the engine of the amount of gasoline required.

As a consequence, an efficient and clean burn occurs. If the mass airflow fails, the ECU will incorrectly compute the gas to inject. Not merely would this light up the Service Engine Soon, the worst to happen is engine damage. It could also lead to the same difficulties as a defective Oxygen sensor.

Bad Oxygen Sensor

The air/fuel ratio in any contemporary vehicle is critical. When this fails, the automobile will not perform efficiently. Insufficient oxygen might be detrimental to the engine if the mixture contains excessive gasoline.

On the other side, too much oxygen can decrease engine power and potential engine damage. A faulty oxygen sensor can potentially have a detrimental effect on the spark plugs or catalytic converter.

Catalytic Converter Failure

A failing catalytic converter is perhaps the most severe possible reason for the Check Engine or Service Engine Soon lights to illuminate. When fuel is burned, they discharge hazardous gasses or fuel vapors into the environment. This is why most automobiles include catalytic converters in their emissions system. Catalytic converters purify the toxic substances emitted by the engine’s exhaust system.

What To Do When Service Engine Soon Light Appears

Suppose your scheduled maintenance is still far and your Service Engine Soon light comes on too early, and you don’t notice any strange noise, odor, or performance of your car. Here are a few ways that might assist you in dealing with such light.

Flashing or Steady and Light Color

Typically, the degree of a problem is indicated by whether it is a flashing or steady light. Certain carmakers go one step forward by color-coding the indication. Solid, steady, or yellow indicates a minor problem that should be resolved quickly.

If it’s red and flashing, this means a serious issue, and you better pull over as soon as possible and promptly switch off your engine. It’s better to get it towed to a repair shop instead of driving it to avoid worsening the car’s damage.

Troubleshoot The Issue

When it’s about auto repairs, there is always someone prepared to do business with you and fix your problem. Most auto shops nowadays are equipped with gadgets and specialists to scan, troubleshoot, and repair the issues with your car. If you’re lucky enough, you’ll find some shops that don’t charge up the scanning procedure.


Suppose you know some automotive basics. You can always DIY the essential solutions such as retightening the gas cap, removing and reattaching the battery cables to reset the system, or inspecting for possible and visible damages. However, if these methods don’t resolve the issue, it’s time to bring your car to a qualified mechanic.


A Service Engine Soon light squawks incessantly if anything is wrong. Allow yourself to be careless for a long enough period, and you may find yourself wandering into a world of headaches. It could be just a loose gas cap, or it could need the replacement of whole sensors.

As costly as it might be, swallowing up the cost for the moment may as well prevent even more expensive repair expenses in the future. It serves as a tip to constantly keep an eye on the state of your vehicle. It’s the same as following your medical routine.

If you treat your automobile with the equal level of care and dedication that you do with yourself, then you may never see the Service Engine Soon light. Always be on the lookout for minor issues or unusual behavior in your automobile. As long as you mind your owner’s manual guidelines, your driving buddy will never disappoint you.


Is service engine soon bad?

It depends on the cause of its light activation. You don’t have to worry if it’s a minor issue. However, a slight problem only worsens if you don’t address it immediately.

How to fix the service engine soon?

In some cases, you can simply switch off the car, unscrew the gas cap, and tightly reinstall it. Perhaps you just missed screwing it down tightly the last time you refueled.

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