What Does Service Engine Soon Mean?

You are driving down the road and suddenly a yellow light reading ‘Service Engine Soon’ comes up on the dashboard. You freeze for a second because any issue related to the engine is supposed to be serious. What does Service Engine Soon mean? Does it warn of a major engine problem? Shall you stop driving immediately and take the car to an auto repair shop?

You have so many questions, right? We’re here to answer them. For now, sit relaxed knowing that the light warns of only minor problems.

What Does Service Engine Soon Mean?

A modern car has loads of sensors for the precise operation of various components. Some of those sensors are connected to the engine. When these sensors detect a malfunction, this Service Engine Soon light comes on as a warning sign.

This light indicates a minor issue with the engine or some electronics connected to it. You can consider it as another Check Engine Light but for trivial issues.

car exhaust system problems
An exhaust system problem may trigger the light. (Photo Source: depositphoto)

Some automakers use only one indicator for small engine problems and schedule service. So, the Service Engine Soon light in your car could be a reminder for the regular maintenance service such as an oil change or replacing the spark plugs.

Causes of the Service Engine Soon Light Coming on

So, you know what does Service Engine Soon mean but what are those issues that trigger the light? Knowing them will help you figure out the exact reason and may save you from an expensive service call.

The Gas Cap

This light can come on because of a loose or defective gas cap or fuel filler cap. Before consulting a mechanic, do a physical inspection of the cap. Tighten in case of a loose cap and keep the tank more than half full. Then, drive the car for about 30 minutes to see if the light goes off. If not, change the cap and try again. Most caps are available within $10 to $20, depending on the make and model.

A loose cap may also trigger an exhaust emission issue. A loose-fitting cap causes the pressure in the gas tank to drop. The emission system’s sensors pick up this pressure drop and set off the light.

Defective Oxygen Sensor

This sensor monitors the amount of unburned oxygen getting released through the exhaust pipe. Any problem with the exhaust components may activate the sensor or a malfunctioning unit can send wrong signals.

Changing the oxygen sensor is an inexpensive fix but neglecting the problem can lead to catalytic converter damage, where the repair cost may cross $2,000.

Issues with the Mass Air Flow (MAF) Sensor

A dirty or bad MAF sensor could also be the culprit. What affects this sensor is the air filter. Incorrect filter installation and a dirty or malfunctioning filter can damage the sensor.

MAF sensor cleaning agents are inexpensive. But you may have to change it if cleaning does not work. You can get it at less than $200.


Misfiring Spark Plugs

Spark plugs have a specific lifespan. Old plugs are less efficient and often cause the engine misfire, which trips the Service Engine Soon light.

If your vehicle is older than the 1996 model year, you will need to replace the spark plugs between 40,000 and 50,000 km. For newer vehicles, this timeline is every 150,000 km.

A misfiring engine falters, hesitates, and feels jumpy when speeding up. It also affects the fuel consumption rate and reduces efficiency.

An Error Code

You already know what does Service Engine Soon mean and the possible causes that trigger the light.

But if these components are working fine, there must be an error code responsible for the light to come on. Check with an OBD2 scanner to find the trouble code. Then, search online to see what kind of problem the code refers to and the solutions. Modern scanners have a built-in code library and automatically show the problem and the solution on the display.

If you don’t have a scanner, consult a mechanic. Repair shops have this machine and they don’t charge much for this service.

How Long Can You Drive with a Service Engine Soon Light?

Well, you know what does the Service Engine Soon mean and how to find out the source of the trouble.

But there is still another thing to consider. How safe is it to drive with this light on? Sure, the problems are trivial, but can they lead to something serious if ignored for long?

What Does Service Engine Soon Mean?
Red light means serious problems. (Photo Source: docplayer)

The truth is, you can drive with this light on for years. The issue is minor if the light does not flicker, but a blinking light indicates an urgent issue and demands immediate repair action. In some vehicles, the light comes in two colors: yellow and red. Yellow is for minor problems and red warns of major troubles.

Any experienced mechanic would advise you to check the affected components as soon as the light comes on, no matter whether it warns of trivial or serious matters.