The Service Engine Soon Light – What it is, What it Means and What to Do When it Comes On

Modern cars are filled with dials, gauges and warning lights, all designed to alert drivers when something is not functioning the way that it should. One of the most important warning lights in any car is the service engine soon light, but many drivers do not fully grasp what it means, let alone know what they should do should it illuminate. 

The purpose of the service engine soon light is to alert drivers that the car’s sensors have detected some sort of malfunction. These sensors are often triggered by issues with the emission control system of the vehicle, but there can be a variety of different causes.

What does the service engine light mean?

The service engine soon light means just what it says – that you should have your engine serviced soon. It does not mean that the engine has broken down, or even that it is in danger of imminent meltdown. What it does mean is that you should make an appointment with your mechanic at your earliest opportunity to trace the source of the malfunction and have the vehicle repaired if necessary. 

If you are driving and your service engine soon light comes on, you should pull over as soon as possible to assess the situation and make a few simple checks. Since the sensors that turn on the service engine soon light are often triggered by a malfunction in the emission control system, the problem could be as simple as a missing or ill-fitting gas cap.

Once you are safely off the road, carefully check the gas cap to make sure it is tight and fully seated. If the gas cap is not properly sealed, it could trigger the emission sensors and activate the service engine soon light.

The service engine soon light can also be triggered by problems with your most recent fill-up of gasoline. If you got gas in the last couple of days and suddenly the service engine soon light is on, that is a good place to start your investigation.

You can begin by asking the service station personnel if there have been additional complaints. If there was water or other contamination in the gas, chances are yours is not the only vehicle affected.

If the car seems to run fine, you can try driving until you deplete a couple of gallons and then topping off the gas tank with new fuel from another service station. If the performance of the vehicle has been compromised, you should make an appointment with your mechanic and have the vehicle checked out right away.

Other problems that could activate the service engine soon light include the oxygen sensor, a device that monitors the way unburned oxygen is released into the environment. Neglecting a faulty oxygen sensor could damage your catalytic converter, resulting in thousands of dollars worth of damage. That is one more reason to have the service engine soon light checked out as soon as possible by a qualified mechanic. 

That having been said, you can probably drive safely with the service engine soon light on, as long as it is on solid and not flashing. If the service engine light is flashing, you should pull over immediately and call for roadside service and have the vehicle towed to the mechanic.

It can be scary when any dash light illuminates, but seeing one with the word engine in the title can be especially alarming. But once you know what the service engine light does and what it really means, you can react more appropriately and make a smart and informed decision.