Why Is My Service Engine Soon Light On? (10 Reasons Why)

Cars have various icons that light up on their dashboard to signal that there is something that the vehicle needs. When a service engine soon light appears, it means that something needs to be replaced or repaired in your engine.

If your service engine soon light is on, you may be wondering what is causing it. We did the research, and here is what we discovered!

Why Is My Service Engine Soon Light On?

Service engine soon light often appears because it means that you need to bring your car in to be serviced. In addition, the service engine soon light illuminates because there is something wrong with the engine. Furthermore, loose gas caps, improperly installed aftermarket car alarms, bad spark plugs, etc., can also be the cause.

Are you curious to learn what other issues cause a service engine soon light to appear? We compiled a list of possibilities below, so keep reading!

1. Scheduled Service

Generally, seeing a service engine soon light on your dashboard means your car is due to get serviced for routine maintenance.

Usually, cars must get serviced every 12,000 miles or once a year to keep the car functioning optimally.

As such, many car manufacturers have added the service engine soon light to remind drivers to have their cars serviced to extend the vehicle’s lifespan.

2. Gas Cap

If you have a loose or damaged gas cap, the gas cap can make your service engine soon light appear.

Generally, the gas cap keeps fuel vapors from leaking out of the filler neck, which can cause hydrocarbon emissions and reduce fuel efficiency.

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If your gas cap is merely loose, you can just remove it and place it back to reset the service engine soon light.

However, if the seal on the gas cap is damaged, you will likely have to get a new gas cap to prevent the service engine soon light from reappearing.

3. Low Engine Oil

Normally, low engine oil in your car can make your service engine light soon appear because there is insufficient oil pressure.

If you have low engine oil and low oil pressure, this will cause your engine to perform poorly, which triggers your service engine soon light and oil light to turn on.

Furthermore, engine oil lubricates the moving parts of your engine to reduce friction and keep the moving parts running smoothly.

Luckily, you can usually top off your engine oil to fix this problem and regularly change the oil as your car’s manual recommends.

4. Low Coolant Levels

Similar to being low on engine oil, having low coolant levels can make your car’s service engine soon light appear.

Usually, lacking coolant in your car will trigger the floating sensor found in your car’s coolant tank, which will make your service engine soon light turn on.

Generally, this turns your service engine soon light on because lacking coolant will cause your car to overheat.

While your engine is meant to get quite hot, coolant moves throughout your car’s engine to keep it from overheating.

5. Lack Of Brake Fluid

Lack Of Brake Fluid

Another common reason why your service engine soon light illuminates is that you are probably low on brake fluid.

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In most modern cars, brake fluid amplifies a foot’s force on the car’s brake pedal, turning the force from your foot into pressure on the car brakes.

When you are low on brake fluid, air will fill in the gaps in your car’s brake line, leading to spongy brakes.

Since spongy brakes are dangerous, it can make your service engine soon light appear because it will be detected as an issue in your car.

6. Failing Catalytic Converter

If your catalytic converter fails, it can trigger your car’s service engine light to illuminate.

Generally, a catalytic converter is part of your exhaust system, which is in charge of turning the toxic gases in your car into less harmful gasses.

However, the catalytic converter can fail for various reasons, such as an overheating engine, cracks, etc.

When this happens, a failing catalytic converter makes the engine perform poorly, dark exhaust smoke, reduced acceleration, and more, making the service engine soon light appear.

7. Bad Sensors

Your car has various sensors that measure specific things within your car’s engine, but when these sensors go bad, they can make your service engine soon light turn on.

Sensors, such as the oxygen sensor, communicate with your car’s engine control computer to make necessary adjustments, like the timing of fuel and air that enters your engine.

If any of these sensors are not working, they will send the wrong information to the engine control computer, which can make the components within your engine unbalanced.

8. Worn Out Spark Plug

Another likely reason why your service engine soon light flashes is that you have a worn-out spark plug.

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As the name suggests, a spark plug is in charge of creating a spark that ignites the combustion that will start your car.

If the spark plug is worn out, there won’t be a spark, which can make your service engine soon light appear on your dashboard.

9. Faulty Ignition Coil

Similar to a spark plug, your ignition coil creates a voltage for your car to start up, but it can go bad and trigger the service engine soon light.

When the ignition coil does not work, it will be impossible or challenging to start the car, causing the service engine soon light to appear.

10. Aftermarket Car Alarms

If you had an aftermarket car alarm installed in your car, it can trigger the service engine soon light, especially if it was improperly installed.

Additionally, an aftermarket car alarm can keep your car from starting, which can also make your service engine soon light turn on.

To know more, you can also read our posts on why your steering wheel is hard to turn, why your key won’t come out of the ignition, and why your engine is shaking.

Conclusion

Normally, your service engine soon light will turn on because there is something wrong with your engine and to warn you that you need to get your car serviced.

However, other parts of your car can make your service engine soon light illuminate, such as the aftermarket car alarm, faulty ignition coils, and more.

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